,,fossil ,,plants ,,cambridge ,,university ,,press ,london3 ,,fetter ,,lane1 ,e4,c4 ,c4 ,f4 ,,clay1 ,,manager ,illustration ,edinburgh3 #ajj1 ,,princes ,,street ,london3 ,h4 ,k4 ,,lewis1 #acf1 ,,gower ,,street1 ,w4,c4 ,berlin3 ,a4 ,,asher ,,and ,,co4 ,leipzig3 ,f4 ,a4 ,,brockhaus ,new ,york3 ,g4 ,p4 ,,putnam',s ,,sons ,bombay and ,calcutta3 ,,macmillan ,,and ,,co41 ,,ltd4 ,all rights reserved ,illustration3 ,part of a transverse section of a ,permian ,osmundaceous ,fern stem1 ,thamnopteris ,schlechtendalii 7,eichwald74 a1 outer xylem2 b1 inner xylem4 ,for description1 see page #cbi4 7,after ,kidston and ,gwynne-,vaughan4 ,very slightly reduced47 ,,fossil ,,plants ,a ,,text-,,book ,,for ,,students ,,of ,,botany ,,and ,,geology ,,by ,a4 ,c4 ,,seward1 ,m4,a41 ,f4,,rs4 ,,professor ,,of ,,botany ,,in ,,the ,,university2 ,,fellow ,,of ,,st ,,john',s ,,college ,,and ,,honorary ,,fellow ,,of ,,emmanuel ,,college1 ,,cambridge ,,with #bfe ,,illustrations ,,vol4 ,,ii ,,cambridge3 ,,at ,,the ,,university ,,press #aiaj ,cambridge3 ,,printed ,,by ,,john ,,clay1 ,m4,a4 ,,at ,,the ,,university ,,press4 ,,preface ,i regret that pressure of other work has prevented the completion of this ,volume within a reasonable time since the publication of ,volume ,i4 ,had ,volume ,,ii been written ten years ago1 the discoveries made in the course of the last decade would have given an out-of-date character to much of the subject-matter4 ,it is more especially in regard to the ,ferns and the extinct members of the ,gymnosperms that our outlook has been materially altered by recent contributions to ,palaeobotany4 ,it is1 however1 some satisfaction to be able to add that recent progress has been relatively slight in that part of the subject dealt with in the first volume4 ,the original intention was to complete the whole work in two volumes4 ,soon after the second volume was begun1 it became evident that the remaining divisions of the plant-kingdom could not be included within the compass of a single volume4 ,i decided1 therefore1 to take the consequences of having embarked on too ambitious a plan of treatment1 and to preserve uniformity of proportion by reserving the seed-bearing plants for a third volume4 ,the third volume will include the ,pteridosperms1 other than those briefly described in the final chapter of the present volume1 and other classes of ,gymnosperms4 ,i propose also to devote such space as is available within the limits of a text-book to the neglected subject of the geographical distribution of plants at different stages in the history of the earth4 ,it is my intention to complete ,volume ,,iii with as little delay as possible4 ,as ,i have written elsewhere1 the past history of the ,flowering plants needs special treatment1 and anything more than a mere compilation can be adequately attempted only after considerable research and with the assistance of botanists possessing a special knowledge of different families of ,angiosperms4 ,the need of a critical examination of available data in regard to the geological history of this dominant group will not be lost sight of4 ,i am well aware that while certain genera have received an undue share of attention in the present volume1 others have been ignored or treated with scant consideration4 ,for this inconsistency ,i have no excuse to offer1 beyond the statement that the subject is a large one1 and selection is necessary even though the work consists of three volumes4 ,the publication in #aiji of a collection of excellent photographs of ,palaeozoic ,plants1 with brief descriptive notes1 by ,mr ,newell ,arber1 as one of a series of popular 8,nature ,books10 bears striking testimony to the remarkable spread of interest in the study of the vegetation of the past1 which is one of the outstanding features in the recent history of botanical science4 ,in the list of illustrations ,i have mentioned the source of all figures which have been previously published4 ,i would1 however1 supplement the statement of fact with an expression of thanks to corporate bodies and to individuals who have allowed me to make use of blocks1 drawings1 or photographs4 ,i wish to thank my colleague1 ,mr ,a4 ,g4 ,tansley1 for placing at my disposal several blocks originally published in the pages of the ,new ,phytologist4 ,to ,professor ,bertrand of ,lille and to his son ,dr ,paul ,bertrand ,i am indebted for several prints and descriptive notes of specimens in their possession4 ,my friends ,dr ,nathorst of ,stockholm and ,dr ,zeiller of ,paris have generously responded to my requests for information on various points4 ,i wish especially to thank ,dr ,kidston for several excellent prints of specimens in his collection and for the loan of sections4 ,i have profited by more than one examination of his splendid collection at ,stirling4 ,professor ,weiss has generously allowed me to borrow sections from the ,manchester ,university collections1 more especially several which have been reproduced in the chapter devoted to the genus ,lepidodendron4 ,to ,professor ,f4 ,w4 ,oliver my thanks are due for the loan of sections from the collection under his charge at ,university ,college4 ,i have pleasure also in thanking ,dr ,scott1 not only for lending me sections of a ,lepidodendron and for allowing me to use some drawings of ,miadesmia originally made by ,mrs ,scott for reproduction in his invaluable book1 ,studies in ,fossil ,botany1 but for kindly undertaking the laborious task of reading the proofs of this volume4 ,it would be unfair to express my gratitude to ,dr ,scott for many helpful suggestions and criticisms1 without explicitly stating that thanks to a friend for reading proofs must not be interpreted as an attempt to claim his support for all statements or views expressed4 ,the ,general ,editor of the ,series1 ,mr ,a4 ,e4 ,shipley1 has also kindly read the proofs4 ,i am under obligations also for assistance of various kinds to ,prof4 ,thomas of ,auckland1 ,new ,zealand1 to ,mr ,boodle of ,kew1 to ,mr ,d4 ,m4 ,s4 ,watson of ,manchester1 to ,mr ,t4 ,g4 ,hill of ,university ,college1 and to ,mr ,gordon of ,emmanuel ,college1 ,cambridge4 ,i am indebted to the kind offices of ,miss ,m4 ,c4 ,knowles for the photograph of the specimen of ,archaeopteris hibernica in the ,irish ,national ,museum1 ,dublin1 reproduced on page #efa4 ,many of the illustrations are reproduced from drawings by my wife3 those made from the actual specimens are distinguished by the addition of the initials ,m4 ,s4 ,i am grateful to her also for some improvements in the letter-press4 ,for the drawings made from sections and for some of the outline sketches ,i am responsible4 ,i have availed myself freely of the facilities afforded by ,professor ,mc,kenny ,hughes in the ,sedgwick ,museum of ,geology for the examination of specimens under the charge of ,mr ,newell ,arber1 the ,university ,demonstrator in ,palaeobotany4 ,it is a pleasure to add that1 as on former occasions1 ,i am indebted to the vigilance of the ,readers of the ,university ,press for the detection of several errors which escaped my notice in the revision of the proofs4 ,a4 ,c4 ,,seward4 ,,botany ,,school1 ,,cambridge4 ,march #ab1 #aiaj4 ,,table ,,of ,,contents ,,chapter ,,xii ,,sphenophyllales 7continued from ,volume ,i474 ,pp4 #a-af4 ,,page ,sphenophyllum #a-g ,cheirostrobus #g-ab ,sphenophyllales and ,psilotaceae #ab-af ,,chapter ,,xiii ,,psilotales4 ,pp4 #ag-bi4 ,psilotum and ,tmesipteris #ag-bd ,fossils described by authors as being closely allied to ,psilotum #bd-bf ,psilophyton #bf-bi ,,chapter ,,xiv ,,lycopodiales4 ,pp4 #cj-ia4 ,recent ,lycopodiales 7,general7 #cj-cc ,lycopodiaceae 7,recent7 #cc-di ,selaginellaceae 7,recent7 #di-eh ,isoetaceae 7,recent7 #eh-ff ,fossil ,lycopodiales #ff-ia ,isoetaceae 7,fossil7 #ff-fh ,pleuromeia #fh-gc ,herbaceous fossil species of ,lycopodiales #gc-ia ,lycopodites #gf-hd ,selaginellites #he-hh ,lycostrobus #hh-ia ,poecilitostachys #ia ,,chapter ,,xv ,,arborescent ,,lycopodiales4 ,pp4 #ib-aie4 ,lepidodendron #ic-aha i4 ,general #ic-ig ii4 ,leaves and ,leaf-cushions #ig-aje iii4 ,lepidophloios #aje-aji iv4 ,the anatomy of ,lepidodendron vasculare #aji-abc v4 ,lepidodendron stems as represented by casts and impressions of partially decorticated specimens #abc-abh a4 ,knorria #abd-abf2 b4 ,bergeria #abf1 #abg2 c4 ,aspidiaria #abg1 #abh4 vi4 ,lepidodendroid axes known as ,ulodendron and ,halonia #abh-aci a4 ,ulodendron #abh-ace2 b4 ,halonia #ace-aci4 vii4 ,anatomical characters of vegetative ,lepidodendron shoots #aci-aha #a4 ,lepidodendron esnostense #aci1 #adj2 #b4 ,l4 rhodumnense #adj2 #c4 ,l4 saalfeldense #ada2 #d4 ,l4 fuliginosum #ada-afj2 #e4 ,l4 ,harcourtii #afj-afc2 #f4 ,l4 ,wnschianum #afc-aga2 #g4 ,l4 macrophyllum #aga2 #h4 ,l4 ,veltheimianum #aga-agg2 #i4 ,l4 ,pedroanum #agg1 #agh2 #aj4 ,l4 australe #agh-aha4 viii4 ,fertile shoots of ,lepidodendreae #aha-aie ,a4 ,lepidostrobus #aha-aia4 i4 ,lepidostrobus variabilis #ahg1 #ahh2 ii4 ,l4 oldhamius #ahh-aij2 iii4 ,l4 ,brownii1 etc4 #aij1 #aia4 ,b4 ,spencerites #aib-aie4 ,,chapter ,,xvi ,,sigillaria4 ,pp4 #aif-bbf4 i4 ,general #aif-baj2 ii4 ,leaves #baj-bae2 iii4 ,fertile shoots #bae-bah2 iv4 ,the structure of ,sigillarian stems #bah-bbd2 v4 ,sigillaria ,brardi #bbd-bbf4 ,,chapter ,,xvii ,,stigmaria4 ,pp4 #bbg-bdg4 ,,chapter ,,xviii ,,bothrodendreae4 ,pp4 #bdh-bgj4 ,bothrodendron #bdh-bfd4 a4 ,b4 minutifolium #bea-bec2 b4 ,b4 punctatum #bed1 #bee2 c4 ,b4 kiltorkense #bee-bei4 ,anatomy of vegetative shoots of ,bothrodendron #bfj-bfb2 ,cones of ,bothrodendron #bfb-bfd4 ,pinakodendron #bfd ,omphalophloios #bfd-bff ,general considerations #bff-bgj ,,chapter ,,xix ,,seed-,,bearing ,,plants ,,closely ,,allied ,,to ,,members ,,of ,,the ,,lycopodiales4 ,pp4 #bga-bgi4 i4 ,lepidocarpon #bga-bge2 ii4 ,miadesmia #bge-bgi4 ,,chapter ,,xx ,,filicales4 ,pp4 #bhj-cbc4 ,i4 ,leptosporangiate ,filicales #bhc-caf ,eufilicineae #bhd-caf4 ,osmundaceae #bhe1 #bhf2 ,schizaeaceae #bhf-bia2 ,matonineae #bia-bic2 ,loxsomaceae #bic2 ,hymenophyllaceae #bid2 ,cyatheaceae #bid-bif2 ,dennstaedtiinae #bif2 ,polypodiaceae #bif2 ,parkeriaceae #big2 ,dipteridinae #bih4 ,the habit1 leaf-form1 and distribution of ferns #cjj-cji2 ,the anatomy of ferns #cji-caf4 ,,ii4 ,marattiales #caf-cba ,,iii4 ,ophioglossales #cba-cbc ,,chapter ,,xxi ,,fossil ,,ferns4 ,pp4 #cbd-cid4 ,osmundaceae #cbd-cdf2 ,schizaeaceae #cdf-cea2 ,gleicheniaceae #cea-cee2 ,matonineae #cee-cfc2 ,hymenophyllaceae #cfc-cfe2 ,cyatheaceae #cfe-cge2 ,polypodiaceae #cge-chj2 ,dipteridinae #chj-cid4 ,,chapter ,,xxii ,,marattiales 7,,fossil74 ,pp4 #cie-daa4 ,ptychocarpus #cig2 ,danaeites #cih2 ,parapecopteris #cih2 ,asterotheca #cih-djj2 ,hawlea #djj2 ,scolecopteris #dja1 #djb2 ,discopteris #djb-djd2 ,dactylotheca #djd-djf2 ,renaultia #djf2 ,zeilleria #djg2 ,urnatopteris #djg2 ,marattiopsis #djg-dji2 ,danaeopsis #dji2 ,nathorstia #daj1 #daa4 ,,chapter ,,xxiii ,,psaronieae4 ,pp4 #dab-dbf4 ,,chapter ,,xxiv ,,ophioglossales 7,,fossil74 ,pp4 #dbg-dca4 ,,chapter ,,xxv ,,coenopterideae4 ,pp4 #dcb-dgb4 ,i4 ,botryoptereae #dcd-ddc ,,ii4 ,zygoptereae #ddc-dgj ,,chapter ,,xxvi ,,hydropterideae ,,and ,,sagenopteris4 ,pp4 #dgc-dhc4 ,marsiliaceae #dgc-dge2 ,salviniaceae #dge-dgg2 ,sagenopteris #dgg-dhc4 ,,chapter ,,xxvii ,,genera ,,of ,,pteridosperms1 ,,ferns1 ,,and ,,plantae ,,incertae ,,sedis4 ,pp4 #dhd-ehj4 ,taeniopteris #dhe-did2 ,weichselia #did-dif2 ,glossopteris #dif-eab2 ,gangamopteris #eab-eag2 ,lesleya #eag-eai2 ,neuropteridium #eai-ebc2 ,cardiopteris #ebc-ebe2 ,aphlebia #ebe-ebi2 ,sphenopteris #ebi-ecb2 ,mariopteris1 ,diplotmema1 ,palmatopteris #ecb-ecg2 ,cephalotheca #ecg2 ,thinnfeldia #ecg-edd2 ,lomatopteris #edd-edf2 ,cycadopteris #edf2 ,ptilozamites #edf-edh2 ,ctenopteris #edh-eej2 ,dichopteris #eej-eeb2 ,odontopteris #eeb-eef2 ,callipteris #eeg-eei2 ,callipteridium #efj2 ,archaeopteris #eeb-efe2 ,neuropteris #efe-ega2 ,cyclopteris #ega1 #egb2 ,linopteris #egb1 #egc2 ,alethopteris #egc-egf2 ,lonchopteris #egf2 ,pecopteris #egf-ehj4 ,,index ,pp4 #fji-fbd ,,list ,,of ,,illustrations ,several of the illustrations are printed from blocks for which ,i am indebted to learned societies or to individuals4 ,the sources from which clichs were obtained are mentioned within square brackets4 ,,frontispiece4 ,thamnopteris ,schlechtendalii 7,eich474 ,from a photograph given to me by ,dr ,kidston and ,mr ,gwynne-,vaughan4 7,page #cbi47 ,,fig4 ,,page #aab4 ,sphenophyllostachys #b #aac4 ,sphenophyllostachys ,rmeri #c ,sphenophyllum trichomatosum ,s4 majus #aad1 #aae4 ,sphenophyllostachys fertilis #d1 #e ,council of the ,royal ,society of ,london4 #aaf4 ,sphenophyllostachys ,dawsoni #f ,mr ,a4 ,g4 ,tansley1 ,editor of the ,new ,phytologist4 #aag4 ,cheirostrobus pettycurensis #h ,pseudobornia ursina #aah4 ,psilotum triquetrum #ah #aai4 ,psilotum triquetrum 7anatomy7 #bj #abj4 ,tmesipteris tannensis #bb #aba4 ,lycopodium 7seven species7 #ce #abb4 ,lycopodium squarrosum #cf #abc4 ,lycopodium cernuum #cg #abd4 ,lycopodium obscurum #ch #abe4 ,lycopodium 7anatomy of stem7 #da #abf4 ,lycopodium 7anatomy of cones7 #de #abg-abi4 ,lycopodium cernuum 7cone7 #dg-di ,council of the ,royal ,society of ,edinburgh4 #acj4 ,selaginella grandis #ej #aca4 ,selaginella 7anatomy7 #eb #acb4 ,isoetes echinospora #ei ,i4 lacustris #acc4 ,isoetes lacustris 7anatomy7 #fb #acd4 ,pleuromeia ,sternbergi #gj #ace4 ,selaginellites and ,lycopodites #hj #acf4 ,lycopodites lanceolatus #ha ,council of the ,geological ,society of ,london4 #acg4 ,lycopodites falcatus #hc #ach4 ,selaginellites primaevus #hf #aci4 ,lycostrobus ,scotti #hi #adj4 ,picea excelsa #id #ada4 ,lepidodendron ,sternbergii #ig #adb4 ,sigillaria 7leaves7 #ih #adc4 ,lepidodendron 7leaves7 #ii #add4 ,lepidodendron ,veltheimianum #aja #ade4 ,lepidodendron leaf-cushion #ajb #adf4 ,lepidodendron and ,lepidophloios leaf-cushions #ajd #adg4 ,lepidophloios leaf-cushion #ajh #adh-aee4 ,lepidodendron vasculare #aab-abb #aef4 ,knorria mirabilis #abe #aeg4 ,lepidodendron ,veltheimianum 7,ulodendron7 #abi #aeh4 ,diagrammatic section illustrating the branch-theory of the ,ulodendroid scar #acb ,council of the ,manchester ,literary and ,philosophical ,society4 #aei4 ,pinus clausa #acd #afj4 ,lepidophloios scoticus #ace #afa4 ,halonia tortuosa #acf #afb-afg4 ,lepidodendron fuliginosum #adc-adg ,council of the ,cambridge ,philosophical ,society4 #afh4 ,lepidodendron vasculare and ,l4 fuliginosum #adh #afi4 ,lepidodendron fuliginosum #adi #agj-agb4 ,l4 fuliginosum #aej-aeb #agc4 ,lepidodendron obovatum #aed #agd-agf4 ,lepidodendron aculeatum #aee1 #aef ,oxford ,university ,press3 ,annals of ,botany4 #agg4 ,stigmaria radiculosa #aeg #agh4 ,stigmarian rootlet #aeh #agi4 ,lepidodendron ,harcourtii and ,l4 fuliginosum #afb #ahj4 ,lepidodendron ,wnschianum #afc #aha1 #ahb4 ,l4 ,wnschianum #afe1 #aff #ahc1 #ahd4 ,l4 ,wnschianum #afh1 #afi ,editor of the ,new ,phytologist4 #ahe4 ,lepidodendron ,veltheimianum #agc #ahf4 ,l4 ,veltheimianum and ,l4 macrophyllum #agf #ahg4 ,lepidodendron australe #agi ,dr ,h4 ,woodward1 ,editor of the ,geological ,magazine4 #ahh1 #ahi4 ,lepidostrobus #ahc1 #ahd #aij4 ,lepidodendron and ,lepidostrobi #ahf #aia4 ,lepidostrobus #ahh #aib4 ,spencerites insignis #aic ,oxford ,university ,press3 ,annals of ,botany4 #aic4 ,sigillaria elegans1 ,s4 rugosa1 ,s4 tessellata1 ,omphalophloios anglicus #aig #aid4 ,sigillaria ,mc,murtriei #aii #aie4 ,sigillaria mammillaris #aii #aif4 ,sigillaria ,brardi1 ,s4 laevigata1 and ,lepidodendron ,wortheni #bjj #aig4 ,carica sp4 #bjb #aih1 #aii4 ,sigillaria #bje1 #bjf #bjj4 ,sigillaria ,brardi #bab #bja4 ,sigillariostrobus #baf #bjb4 ,sigillaria elegans and ,s4 elongata #bbj #bjc4 ,sigillaria ,brardi #bbe #bjd1 #bje4 ,stigmaria ficoides #bbg1 #bbh #bjf4 ,cyperus papyrus #bcj #bjg1 #bjh4 ,stages in the development of ,sigillaria #bcf #bji4 ,stigmariopsis #bcg #baj4 ,stigmaria #bda #baa4 ,bothrodendron punctatum #bej #bab4 ,bothrodendron minutifolium1 ,b4 punctatum1 ,b4 kiltorkense and ,lepidostrobus ,olryi #beb #bac4 ,bothrodendron minutifolium #bed #bad4 ,bothrodendron ,leslei #beh ,trustees of the ,british ,museum4 #bae4 ,bothrodendron mundum #bei #baf4 ,bothrostrobus #bfc ,council of the ,manchester ,literary and ,philosophical ,society4 #bag4 ,omphalophloios #bfe #bah4 ,lepidocarpon ,lomaxi #bgc #bai4 ,miadesmia and ,bothrodendron #bgf #bbj4 ,angiopteris evecta and ,cycas revoluta #bhc #bba4 ,osmunda cinnamomea1 ,o4 regalis1 and ,todea barbara #bhf #bbb4 ,schizaea elegans #bhg #bbc4 ,aneimia rotundifolia #bhh #bbd4 ,aneimia flexuosa1 ,a4 phyllitidis1 ,hymenophyllum1 ,matonia pectinata1 ,thyrsopteris elegans1 ,gleichenia #bhi #bbe4 ,gleichenia dicarpa #bij #bbf4 ,gleichenites ,rostafinskii1 ,gleichenia dicarpa1 ,g4 dichotoma #bij #bbg4 ,matonia pectinata #bib ,council of the ,royal ,society4 #bbh4 ,matonia pectinata #bic #bbi4 ,thyrsopteris elegans1 ,cyathea spinulosa1 ,dicksonia coniifolia1 ,d4 culcita1 ,davallia concinna1 ,alsophila excelsa #bid #bcj4 ,dicksonia ,bertervana #bie ,trustees of the ,british ,museum4 #bca4 ,dipteris quinquefurcata1 ,d4 conjugata1 ,d4 ,wallichii1 and ,polypodium quercifolium #big #bcb4 ,davallia aculeata #bii #bcc4 ,polypodium ,billardieri #cjb #bcd4 ,polypodium quercifolium #cjc #bce4 ,hemitelia capensis #cjd #bcf a1 #bcf b4 ,pteris aquilina #cje1 #cjf ,council of the ,linnean ,society of ,london4 #bcg4 ,matonia pectinata1 ,matonidium1 ,gleichenia dicarpa1 and ,trichomanes reniforme 7anatomy7 #caj #bch4 ,trichomanes scandens #caa ,editor of the ,new ,phytologist4 #bci4 ,platyzoma microphylla #cab ,editor of the ,new ,phytologist4 #bdj4 ,cyathea ,imrayana #cac ,editor of the ,new ,phytologist44 #bda4 ,angiopteris evecta and ,marattia fraxinea #cag #bdb4 ,angiopteris evecta and ,danaea #cah #bdc1 #bdd4 ,angiopteris evecta #cai #bde4 ,marattia fraxinea1 ,m4 ,kaulfussii1 ,kaulfussia1 and ,marattiopsis ,mnsteri #cbj #bdf4 ,ophioglossum vulgatum #cbb #bdg4 ,botrychium virginianum #cbb #bdh4 ,zalesskya gracilis #cbg #bdi4 ,zalesskya diploxylon #cbh #bej4 ,thamnopteris ,schlechtendalii #ccj #bea4 ,lonchopteris virginiensis #cca #beb4 ,osmundites ,dunlopi #ccc #bec1 #bed4 ,osmundites ,kolbei #ccd1 #cce ,editor of the ,geological ,magazine4 #bee4 ,o4 ,kolbei #ccf #bef4 ,cladophlebis denticulata1 ,todites ,williamsoni1 ,discopteris ,rallii1 ,kidstonia heracleensis1 and ,todeopsis primaeva #cdj #beg1 #beh4 ,cladophlebis denticulata #cdb1 #cde #bei4 ,klukia exilis #cdh ,council of the ,cambridge ,philosophical ,society4 #bfj4 ,ruffordia ,goepperti #cdi #bfa4 ,chrysodium lanzaeanum1 ,lygodium ,kaulfussi1 ,marattia ,hookeri #cej #bfb4 ,gleichenites longipennis1 ,g4 delicatula1 ,g4 ,nordenskioldi and ,g4 ,zippei #ced #bfc4 ,gleichenites hantonensis #cef ,council of the ,palaeontographical ,society4 #bfd4 ,laccopteris elegans #ceg ,council of the ,royal ,society4 #bfe4 ,matonidium ,wiesneri1 ,marattiopsis marantacea1 ,gleichenites gracilis1 ,laccopteris ,goepperti1 and ,l4 ,muensteri #ceh #bff4 ,laccopteris polypodioides #cei ,trustees of the ,british ,museum4 #bfg4 ,laccopteris #cei ,trustees of the ,british ,museum4 #bfh4 8 ,laccopteris polypodioides #cfj ,trustees of the ,british ,museum4 #bfi4 ,matonidium ,goepperti #cfb ,editor of the ,encyclopaedia ,britannica4 #bgj4 ,senftenbergia elegans1 ,oligocarpia ,brongniartii1 ,trichomanes sp41 ,hymenophyllum tunbridgense1 ,sphenopteris 7,hymenophyllites7 quadridactylites #cfd #bga4 ,coniopteris hymenophylloides #cfh ,council of the ,manchester ,literary and ,philosophical ,society4 #bgb4 ,c4 hymenophylloides #cfi #bgc4 ,coniopteris quinqueloba #cgj #bgd4 ,coniopteris arguta #cga #bge4 ,coniopteris arguta and ,c4 hymenophylloides #cgb #bgf4 ,oncopteris ,nettvalli #cgc #bgg4 ,protopteris punctata #cgc #bgh4 ,laccopteris polypodioides1 ,l4 ,muensteri1 ,dicksonia1 ,onychiopsis ,mantelli1 ,hausmannia ,sewardi1 ,h4 ,kohlmanni1 and ,protopteris ,witteana #cgd #bgi4 ,adiantides antiquus and ,a4 lindsayoides #cgf #bhj4 ,onychiopsis ,mantelli #cgi #bha4 ,dictyophyllum exile #cha #bhb4 ,dictyophyllum ,nilssoni1 ,rhizomopteris ,schenki1 ,camptopteris spiralis1 and ,d4 exile #chb #bhc4 ,dictyophyllum rugosum #chd ,trustees of the ,british ,museum4 #bhd4 ,thaumatopteris ,mnsteri #chf #bhe4 ,clathropteris meniscoides #chg #bhf4 ,clathropteris egyptiaca #chh ,editor of the ,geological ,magazine4 #bhg4 ,camptopteris spiralis #chi #bhh4 ,hausmannia dichotoma #cia #bhi4 ,hausmannia sp4 #cic #bij4 ,alethopteris lonchitica1 ,lonchopteris rugosa1 ,sphenopteris ,hoeninghausi1 ,parapecopteris neuropteroides1and ,pecopteris 7,dactylotheca7 plumosa #cii #bia4 ,ptychocarpus unita1 ,asterotheca ,sternbergii1 ,danaeites sarepontanus1 ,hawlea ,miltoni1 ,h4 pulcherrima1 ,scolecopteris elegans #djj #bib4 ,dactylotheca plumosa #dje #bic4 ,d4 plumosa #djf #bid4 ,nathorstia angustifolia and ,n4 latifolia #daj #bie4 ,psaronius #dad #bif4 ,psaronius infarctus1 ,p4 coalescens1 ,p4 musaeformis1 and ,p4 asterolithus #daf #big4 ,pecopteris ,sterzeli #dai #bih4 ,caulopteris peltigera and ,megaphyton insigne #dba #bii4 ,ptychopteris #dbc #cjj4 ,dicksonia antarctica #dbd #cja4 ,rhacopteris sp4 #dbg #cjb4 ,noeggerathia foliosa #dbi #cjc4 ,chiropteris ,zeilleri #dcj ,annals of the ,south ,african ,museum4 #cjd4 ,tubicaulis solenites #dce ,editor of the ,new ,phytologist4 #cje4 ,botryopteris cylindrica #dci #cjf4 ,botryopteris ramosa #dda #cjg4 ,botryopteris antiqua #ddb #cjh4 ,clepsydropsis antiqua1 ,etapteris ,scotti1 ,diplolabis forensis1 ,zygopteris primaria1 ,stauropteris oldhamia #ddd #cji4 ,diplolabis forensis1 ,botryopteris forensis1 ,corynepteris coralloides1 ,schizopteris pinnata #dde #caj4 ,metaclepsydropsis duplex1 ,stauropteris oldhamia1 ,ankyropteris scandens #dej #caa4 ,ankyropteris ,grayi #dea #cab4 ,thamnopteris ,schlechtendalii1 ,ankyropteris corrugata1 ,a4 bibractensis #dec #cac4 ,ankyropteris bibractensis #ded #cad4 ,ankyropteris corrugata #deg #cae4 ,ankyropteris corrugata #deh ,editor of the ,new ,phytologist4 #caf1 #cag4 ,ankyropteris corrugata #dei1 #dfj #cah4 ,etapteris ,scotti #dfb ,editor of the ,new ,phytologist4 #cai4 ,etapteris1 ,botryopteris forensis #dfc #cbj4 ,stauropteris oldhamia #dfd ,editor of the ,new ,phytologist4 #cba4 ,stauropteris oldhamia #dfg #cbb4 ,stauropteris oldhamia #dfh ,editor of the ,new ,phytologist4 #cbc4 ,stauropteris #dfi ,editor of the ,new ,phytologist4 #cbd4 ,asterochlaena laxa #dgb ,editor of the ,new ,phytologist4 #cbe4 ,sporocarp-like bodies 78 ,sagenopteris7 #dgh #cbf4 ,regnellidium diphyllum1 ,sagenopteris rhoifolia #dgi #cbg4 ,sagenopteris ,phillipsi #dhj ,trustees of the ,british ,museum4 #cbh4 ,sagenopteris ,phillipsi #dha ,council of the ,manchester ,literary and ,philosophical ,society4 #cbi4 ,taeniopteris multinervis1 ,lesleya ,delafondi #dhg #ccj4 ,taeniopteris ,carnoti1 ,t4 spatulata1 ,t4 coriacea #dij #cca4 ,taeniopteris ,carruthersi #dia ,annals of the ,south ,african ,museum4 #ccb4 ,taeniopteris vittata #dic #ccc4 ,weichselia ,mantelli1 ,w4 erratica #die #ccd4 ,glossopteris ,browniana #dii ,council of the ,geological ,society of ,london4 #cce1 #ccf4 ,glossopteris ,browniana #ejj1 #eja ,trustees of the ,british ,museum4 #ccg4 ,vertebraria indica #ejb #cch4 ,vertebraria indica1 ,onoclea struthiopteris #ejc #cci4 ,glossopteris fronds attached to rhizome #ejd #cdj1 #cda4 ,glossopteris indica1 ,g4 angustifolia #ejf1 #ejg ,trustees of the ,british ,museum4 #cdb4 ,glossopteris angustifolia var4 taeniopteroides #ejh ,council of the ,geological ,society4 #cdc4 ,blechnoxylon talbragarense #eji #cdd4 ,glossopteris retifera #eaa ,trustees of the ,british ,museum4 #cde4 ,gangamopteris cyclopteroides #eae ,trustees of the ,british ,museum4 #cdf4 ,arberia sp4 #eag #cdg4 ,lesleya simplicinervis #eah #cdh4 ,neuropteridium validum #ebj ,trustees of the ,british ,museum4 #cdi4 ,neuropteridium intermedium #ebb #cej4 ,cardiopteris frondosa #ebd #cea4 ,gunnera manicata #ebg #ceb4 ,sphenopteris obtusiloba1 ,pecopteris arborescens1 ,sphenopteris furcata #ebi #cec4 ,sphenopteris affinis #eca #ced4 ,palmatopteris1 ,mariopteris1 ,diplotmema ,zeilleri1 ,neuropteris macrophylla1 ,n4 heterophylla1 ,n4 ,scheuchzeri1 ,alloiopteris ,essinghii #ece #cee4 ,cephalotheca mirabilis #ecf #cef4 ,thinnfeldia odontopteroides1 ,ptilozamites #eci ,council of the ,geological ,society4 #ceg4 ,thinnfeldia odontopteroides #edj ,council of the ,geological ,society4 #ceh4 ,thinnfeldia odontopteroides #eda ,annals of the ,south ,african ,museum4 #cei4 ,thinnfeldia rhomboidalis #edb #cfj4 ,lomatopteris jurensis1 ,l4 ,schimperi1 ,thinnfeldia rhomboidalis #edd #cfa4 ,ptilozamites ,heeri #edg #cfb4 ,ctenopteris cycadea #edi #cfc4 ,dichopteris visianica #eea #cfd4 ,alethopteris lonchitica1 ,mariopteris muricata1 ,odontopteris cf4 alpina #eec #cfe4 ,odontopteris minor #eed #cff4 ,odontopteris genuina1 ,callipteridium gigas1 ,callipteris ,pellati1 ,c4 lyratifolia #eeg #cfg4 ,callipteris conferta #eei #cfh4 ,archaeopteris hibernica #efa #cfi4 ,archaeopteris hibernica1 ,a4 archetypus1 ,a4fissilis1 ,a4 fimbriata #efd #cgj4 ,neuropteris with ,cyclopteris leaflets #eff ,from a block received from ,mr ,carruthers4 #cga4 ,neuropteris heterophylla #efh #cgb4 ,neuropteris macrophylla #efi #cgc4 ,neuropteris ,scheuchzeri #egj #cgd4 ,linopteris neuropteroides #egc #cge4 ,alethopteris ,serlii #ege #cgf4 ,pecopteris arborescens #egh ,,errata ,,in ,,vol4 ,i ,page #af1 line #d4 ,for 8,the ,north ,american ,tulip tree0 read ,the ,tulip tree of ,north ,america and ,china4 #ff1 line #b from the bottom4 ,for 8,browera0 read ,berowra4 #abg1 line #c and #d from bottom4 ,for ,achyla and ,palaeachyla read ,achlya and ,palaeachlya4 #ade1 lines #d and #e4 ,for 8,upper ,greensand0 read ,lower ,eocene4 #afb1 line #c from bottom4 ,for 8,corallina barbata0 read ,cymopolia barbata4 #agj1 line #bj4 ,for 8sporangiaphore0 read sporangiophore4 #ahe1 line #b4 ,the genera ,udotea and ,halimeda1 members of the ,siphoneae1 are incorrectly included under the ,corallinaceae4 #aia1 line #aa from bottom4 ,omit ,chondrus crispus1 which is one of the ,florideae and not a ,brown ,alga4 #bjb1 line #ac4 ,for 8,halmeda0 read ,halimeda4 #bej1 line #aa4 ,for 8three0 read the4 #cha1 line #aj4 ,for 8,calamopytus0 read ,calamopitys4 ,,chapter ,,xii#a4 ,,sphenophyllales 7concluded74 ,sphenophyllum4 ,the account of the ,sphenophyllales given in the first volume#b of this work must be extended and somewhat modified in the light of recent work on the fertile shoots of ,sphenophyllum4 ,sphenophyllostachys ,dawsoni 7,will47 was described as consisting of an axis bearing superposed whorls of bracts connate at the base in the form of a shallow funnel-shaped collar giving off from the upper surface and close to the axis of the cone two concentric series of sporangiophores4 ,occasionally there are three series1 as represented in fig4 #aab4 ,in another type of strobilus1 ,sphenophyllostachys ,rmeri#c each sporangiophore terminates in two pendulous sporangia 7fig4 #aac1 ,a2 see also fig4 #ajg1 ,c1 vol4 ,i474 ,it has already been pointed out that the common occurrence of detached strobili necessitates their description under distinct specific names2 it is only by a rare accident that we can assign fossil cones to their vegetative shoots4 ,there are1 however1 reasons for believing that ,sphenophyllostachys ,dawsoni is the strobilus of the plant originally described by ,sternberg#d from impressions of foliage-shoots as ,rotularia cuneifolia4 ,another difficulty presented by petrified material is that of determining1 with certainty1 whether two imperfect specimens1 differing from one another in features which do not appear to be of sufficient importance to warrant specific separation1 are forms of one species or portions of specifically distinct cones4 ,it has been pointed out by ,scott#e that the strobilus known as ,sphenophyllostachys ,dawsoni probably includes two distinct species1 one being the cone of ,sphenophyllum cuneifolium ,sternb41 and the other the cone of ,s4 myriophyllum ,crp#f4 ,the stem of ,s4 myriophyllum agrees anatomically with the type known as ,sphenophyllum plurifoliatum ,will4 and ,scott#g4 ,illustration3 ,,fig4 #aab4 ,sketch of a radial longitudinal section of ,sphenophyllostachys4 ,there are usually two concentric series of sporangia on the sporophylls1 not three as shown in the figure4 ,the upper figure 7after ,zeiller7 shows the linear bracts in surface-view4 ,in addition to the two types of cone already mentioned1 ,sphenophyllostachys ,dawsoni and ,s4 ,rmeri1 others have been described by ,kidston from carbonised impressions4 ,one of these is the fertile branch of ,sphenophyllum majus#h4 ,the basal portions of the bracts of each whorl form a narrow collar round the axis of the cone2 the free portion of each bract consists of a lamina divided into two equal bifid lobes bearing on its upper surface one group1 or possibly two groups1 of four sessile sporangia between the narrow coherent bases of the laminae and the sinus between the terminal lobes 7fig4 #aac1 ,c74 ,another characteristic feature is the greater length of the internodes2 this renders the cone less compact and less sharply differentiated from the vegetative shoots than those of other species4 ,a specimen in ,dr ,kidston's collection illustrates the peculiar character of the fertile portion of this species2 it consists of an axis bearing a succession of lax sporophylls succeeded above and below by whorls of sterile leaves4 ,in this species1 therefore1 we cannot speak of a compact strobilus at the end of a shoot of limited growth1 but of axes in which sterile and fertile leaves are borne alternately#i1 a condition recalling the alternation of foliage leaves and sporophylls in ,tmesipteris and in ,lycopodium ,selago4 ,illustration3 ,,fig4 #aac4 ,a4 ,sphenophyllostachys ,rmeri4 7,solms-,laubach47 ,b4 ,sphenophyllum trichomatosum ,stur4 ,c4 ,sphenophyllum majus4 ,bronn4 7,a-,c4 ,after ,kidston47 ,another form of cone1 also from the ,middle ,coal ,measures1 is referred by ,kidston to ,sphenophyllum trichomatosum ,stur#aj 7fig4 #aac1 ,b73 this is characterised by the more horizontal position of the bracts1 which 8do not appear to be so much or so suddenly bent upwards in their distal portion as in some other species of ,sphenophyllum10 and by sessile sporangia borne singly on the upper face of each bract4 ,illustration3 ,,fig4 #aad4 ,sphenophyllostachys fertilis 7,scott74 7,after ,scott47 ,diagram of a node in longitudinal section1 showing one sporophyll and the base of the opposite one4 v4l4 ventral lobe of sporophyll2 v4s4 one of the segments into which it divides2 v4s4 stump of another segment2 d4l4 dorsal lobe2 d4s41 d4s4 segments of dorsal lobe4 ,a more recent addition to our knowledge of the fertile shoots of ,sphenophyllum is due to ,scott who has described a new type of cone under the name ,sphenophyllum fertile#aa4 ,the petrified specimen on which the species was founded was discovered by ,mr ,james ,lomax in the ,lower ,coal ,measures of ,lancashire2 it represents a portion of a cone #f cm4 long and approximately #ab mm4 broad4 ,the axis contains a single vascular cylinder agreeing in essentials with the type of stem structure known as ,sphenophyllum plurifoliatum4 ,the nodal regions1 which exhibit the slight swelling characteristic of the genus1 bear several 7probably twelve7 appendages connate at the base and forming a narrow flange encircling the axis4 ,each bract1 the base of which forms part of the narrow collar surrounding the axis1 consists of two lobes1 ventral and dorsal1 divided palmately into several 7sometimes four7 segments or sporangiophores 7fig4 #aae74 ,each sporangiophore terminates distally in an oblong or oval lamina bearing two sporangia on its adaxial face 7fig4 #aad74 ,the space between the axis and the periphery of the cone is thus occupied by crowded peltate laminae1 each with its pair of sporangia4 ,a single vascular bundle supplies each sporangiophore and bifurcates in the distal lamina into two branches which extend to the bases of the sporangia4 ,the sporangia agree in structure with those of other species of ,sphenophyllum3 the spores are of one size and elliptical1 characterised by the presence of several sharp ridges or flanges encircling the spore-wall in the direction of the major-axis4 ,sphenophyllostachys fertilis differs from all previously recorded types in the absence of sterile bracts4 ,the appendages of the cone-axis are all fertile1 a striking contrast to the differentiation into protective and sporangia-bearing bracts which constitutes a constant feature in the cones of ,sphenophyllum and ,calamites4 ,it is possible1 as ,scott suggests1 that the absence of sterile segments is the result of modification of the more usual type of strobilus2 instead of the dorsal and ventral lobes of the bracts sharing between them the duties of protection and spore-production1 the whole of each bract is constructed on the plan of the maximum spore-output1 the laminar terminations of the sporangiophores serving the purpose of protection4 ,the cone may be described as more specialised than the normal type of strobilus for reproductive purposes#ab4 ,illustration3 ,,fig4 #aae4 ,sphenophyllostachys fertilis 7,scott74 7,after ,scott47 ,diagram of a single sporophyll as it would appear in a transverse section of the cone2 showing one lobe 7dorsal or ventral74 ax1 part of axis to which the sporophylls are attached4 ,illustration3 ,,fig4 #aaf4 ,sphenophyllostachys ,dawsoni4 7,after ,thoday47 ,a4 ,larger spores2 ,b1 abortive spores2 ,c1 mature spores showing the characteristic spines4 ,it has been stated1 on evidence which is unsatisfactory1 that ,sphenophyllum possesses two kinds of spores4 ,while regarding the genus as homosporous on the evidence before us1 it is interesting to find that cases occur in which the spores in the same sporangium exhibit a marked difference in size4 ,attention has been called by ,williamson and ,scott#ac to variation in the dimensions of spores3 a more pronounced difference in size has been recorded by ,mr ,thoday#ad who gives #abj as the maximum and #ij as the minimum diameter of the spores in a cone of ,sphenophyllostachys ,dawsoni4 ,the presence of several abortive spores in the sporangium 7fig4 #aaf7 containing the larger spores favours the view that this difference in size may be the first step towards the development of heterospory4 ,it is clear that the types of strobilus designated ,sphenophyllostachys 7figs4 #aab-aad7 present a divergence of characters too great to be comprised under one genus2 but in the absence of fuller information1 we cannot do otherwise than follow the only logical custom of grouping them together as examples of strobili borne by plants which1 in the present state of our knowledge1 are most conveniently referred to the genus ,sphenophyllum4 ,cheirostrobus4 ,this generic name was applied by ,dr ,scott#ae to a calcified cone obtained by ,mr ,james ,bennie in #ahhc from the ,lower ,carboniferous plant-beds of ,pettycur near ,burntisland on the ,firth of ,forth4 ,cheirostrobus is distinguished from ,sphenophyllostachys by its greater breadth 7#c4e cm472 externally it agrees more closely with the fertile shoots of ,lepidodendron than with those of ,sphenophyllum4 ,a single vascular cylinder having the form of a fluted ,doric column 7fig4 #aag1 ,b1 x7 occupies the axis of the cone3 it consists for the most part of reticulate tracheae which tend to assume a short or isodiametric form in the central region2 the smaller protoxylem tracheids with the spiral form of pitting constitute the sharp and prominent ridges at the periphery of the xylem-cylinder4 ,in the outer part of the cylinder the metaxylem#af consists exclusively of tracheae1 but towards the centre of the axis these are associated with numerous parenchymatous cells4 ,the xylem is therefore centripetal in origin as in ,sphenophyllum and in nearly all recent and fossil members of the ,lycopodiales4 ,in the type-specimen of ,cheirostrobus the vascular cylinder of the cone consists entirely of primary xylem1 but secondary xylem has been found in a more recently discovered specimen#ag4 ,secondary xylem occurs also in the peduncle of the cone4 ,no appreciable remains of phloem have been found4 ,the cortex consists of slightly elongated rather thick-walled tissue containing secretory sacs4 ,crowded superposed whorls of bracts 7or sporophylls71 usually twelve in each whorl1 are borne on the axis and each sporophyll receives a single vascular bundle from one of the vertical ridges of the xylem column 7fig4 #aag1 ,a1 lt74 ,the members of each whorl are connate at the base3 from this narrow collar each sporophyll branches into an upper or dorsal and a lower or ventral limb 7fig4 #aag1 ,a1 f and s74 ,each limb divides palmately at a short distance from its origin into three slender segments1 which extend in a horizontal direction and terminate in large laminar expansions 7fig4 #aag1 ,b1 s7 to afford a protective covering to the surface of the cone4 ,the upper set of three segments1 constituting sporangiophores 7fig4 #aag1 ,a1 ,b1 f7 or fertile divisions of the sporophyll1 expand distally into comparatively bulky laminae2 each of these bears on its adaxial face four diagonally placed outgrowths which form the short pedicels of very long and narrow sporangia4 ,the three lower segments--the sterile divisions of the sporophylls--7fig4 #aag1 ,a1 ,b1 s7 are similar to the upper set except in their greater length and in the kite-shaped form of their distal laminae which are provided with lateral lobes4 ,the single vascular strand which supplies each sporophyll is represented at lt in fig4 #aag1 ,b2 at lt the strand has divided into four1 the three upper bundles in the figure supply the sterile segments and the single lower bundle ultimately divides into three which supply the fertile segments4 ,a pair of blunt processes 7fig4 ,a1 s7 extend downwards over the ends of the underlying fertile lamina and two slender prolongations extend upwards through several internodes4 ,illustration3 ,,fig4 #aag4 ,a1 ,b4 ,cheirostrobus pettycurensis ,scott4 7,after ,scott47 ,c1 ,d4 ,pseudobornia ursina ,nath4 7,after ,nathorst47 ,a4 ,diagrammatic radial longitudinal section of part of the cone-axis and two sporophylls4 lt1 bundle passing out to sporophyll2 f1 fertile segment of sporophyll showing two sporangia2 s1 sterile 7lower7 segment4 ,b4 ,part of transverse section4 x1 stele2 lt1 lt1 bundles on their way to sporophylls2 a1 tips of sterile segments of lower sporophylls4 ,c4 ,palmately branched leaf 7 natural size74 ,d4 ,node of stem showing leaf-bases4 ,an economical arrangement of the long and narrow sporangia and of the sporophyll-segments between the axis and the periphery of the cone is rendered possible by the interlocking of the sterile and fertile segments by means of a groove in the upper face of the latter for the accommodation of the former4 ,the sporangia are characterised by their unusually long and narrow form3 the length of a sporangium may reach #a centimetre4 ,in the structure of the wall the sporangia of ,cheirostrobus agree closely with those of ,calamostachys#ah and ,sphenophyllostachys4 ,the spores are of one size only4 ,the vascular cylinder of the peduncle1 originally described by ,williamson#ai as the peduncle of a large ,lepidostrobus 7the cone of ,lepidodendron71 is characterised by the presence of a short radially disposed zone of secondary tracheids1 a feature1 as ,scott points out1 which may extend into the axis of the cone4 ,it is noteworthy that the protoxylem elements are not always external1 but occasionally occur internal to one or two of the outermost metaxylem tracheae3 the usual exarch#bj structure of the central cylinder is not therefore absolutely constant1 but may be replaced by a mesarch arrangement4 ,the presence of a few sterile leaves on the peduncle below the fertile portion of the cone1 which agree in their lobed laminae with the sporophylls1 is the only fact which we possess as to the form of the vegetative characters of the genus4 ,the above description is sufficient to indicate the extraordinary complexity and high degree of specialisation of ,cheirostrobus4 ,the sporophylls1 with their trilobed segments1 and the crowded sporangia of exceptional length attached only by a narrow base constitute striking peculiarities of the genus4 ,it is unfortunate that we are still without any satisfactory evidence as to the nature of the plant the cones of which have been made the type of a new genus and a new family4 ,cheirostrobus affords an interesting example of a type of reproductive shoot constructed on a plan sui generis1 and may be classed with some other extinct genera as instances of the production in the course of evolution of architectural schemes which appear to have been ill adapted for competition with equally efficient though much simpler types4 ,but the discovery of these isolated forms of restricted geological range among the relics of the ,palaeozoic vegetation frequently supplies a key to phylogenetic problems4 ,cheirostrobus by its complex combination of features characteristic of the ,equisetales1 the ,lycopodiales and the genus ,sphenophyllum throws a welcome light on the inter-relationships of groups which represent divergent series4 ,the combination of morphological features in this generalised type led the author of the genus to describe it as a descendant of an old stock which existed prior to the divergence of the ,equisetales and ,lycopodiales4 ,the discovery of this new type of strobilus naturally led to a search among ,lower ,carboniferous plants for vegetative shoots exhibiting characters conformable with the whorled and branched leaves of ,cheirostrobus4 ,in ,sphenophyllum we have a genus obviously comparable with ,cheirostrobus as regards the form and disposition of the leaves1 but the differences between the cones and the striking similarity of the vascular cylinder of the latter to that of ,lepidodendron demonstrate conclusively that we must look elsewhere for the vegetative members of the plant which produced cones of the ,cheirostrobus type4 ,sidenote3 ,,pseudobornia ,in #aijb ,professor ,nathorst#ba instituted the generic name ,pseudobornia for plants of which imperfect examples had previously been referred by ,heer#bb to ,calamites under the name ,c4 radiatus4 ,heer's plants were obtained from ,upper ,devonian rocks of ,bear ,island in the ,arctic seas and additional specimens were brought from the same locality by the ,swedish ,polar ,expedition of #ahih4 ,pseudobornia possesses jointed stems 7fig4 #aag1 ,d7 bearing whorled and shortly stalked leaves1 often four in number1 at each node4 ,the leaves are palmately branched with fine serrated edges 7fig4 #aag1 ,c74 ,certain specimens1 which are no doubt correctly described by ,nathorst as cones1 are characterised by a thick axis bearing whorled leaves with sporangia on their lower surfaces1 but the material is not sufficiently well preserved to render possible a recognition of structural details4 ,it has been suggested by ,scott that ,pseudobornia may possibly be referable to the ,sphenophyllales and that the stem of ,cheirostrobus 8may have had something in common with0 ,nathorst's genus#bc4 ,the beds in which the stems occur are of ,upper ,devonian age1 while ,cheirostrobus was found in ,lower ,carboniferous rocks3 this difference in age is not1 however1 a serious objection to the validity of the comparison4 ,we cannot do more than express the view that ,pseudobornia1 so far as can be ascertained without an examination of petrified material or of more perfect impressions of strobili1 exhibits vegetative features not inconsistent with the morphological characters of the fertile shoots known as ,cheirostrobus4 ,the institution of a special group-name for the reception of ,sphenophyllum is justified by the sum of its morphological features1 which do not sufficiently conform to those of any existing group of ,pteridophytes to warrant its inclusion in a system of classification based on recent genera4 ,in the case of ,cheirostrobus we are limited to the characters of the cone and its peduncle4 ,the suggestion that the ,devonian fossils known as ,pseudobornia may represent the foliage shoots of a plant closely related to ,cheirostrobus has still to be proved correct4 ,although we may find justification in the highly complex and peculiar structure of ,cheirostrobus for the recognition of the genus as a type of still another group of ,pteridophytes1 it would be unwise to take this step without additional knowledge4 ,the undoubted similarity between ,cheirostrobus and ,sphenophyllum coupled with striking points of difference favours the inclusion of the two genera in distinct families placed1 for the present at least1 in the group ,sphenophyllales4 ,group ,,sphenophyllales4 ,sphenophylleae3 genus ,sphenophyllum4 ,cheirostrobeae3 genus ,cheirostrobus4 ,it has recently been proposed to include the family ,psilotaceae1 comprising the two recent genera ,psilotum and ,tmesipteris1 as another subdivision of the ,sphenophyllales4 ,this proposal had been made by ,professor ,thomas#bd primarily on the ground that the sporophylls of ,tmesipteris and ,psilotum appear to afford the closest parallel among existing plants to the peculiar form of sporophyll characteristic of the ,sphenophyllales4 ,the morphological interpretation of the sporophylls of both ,sphenophyllum and ,cheirostrobus has been the source of considerable discussion#be4 ,if we regard each sporophyll as a leaf with two lobes1 one fertile and one sterile1 except in the case of ,sphenophyllostachys fertilis in which both are fertile1 an obvious comparison may be made with the fern ,ophioglossum2 but the difference between a single fern frond1 consisting of a comparatively large sterile lamina bearing a fertile branch composed of a long axis with two rows of sporangia embedded in its tissues1 and the whorled sporophylls of ,sphenophyllum is considerable4 ,sidenote3 ,,psilotaceae ,a brief reference may be made to the principal reasons which have led to the suggestion that the ,psilotaceae should be included in the ,sphenophyllales4 ,the shoots of ,tmesipteris bear simple foliage leaves spirally disposed on a slender axis1 and in association with these occur sporophylls consisting of a short axis bearing a pair of small lobes and a bilocular synangium#bf 7fig4 #abj1 ,b74 ,the synangium is seated on a very short stalk given off from its sporophyll at the base of the pair of laminae3 the synangium with its short stalk may be spoken of as the sporangiophore4 ,in most cases the synangium appears to be sessile on the sporophyll1 but occasionally the much reduced stalk is prolonged and forms an obvious feature4 ,dr ,scott#bg suggested that the ,tmesipteris synangium with its axis may correspond to the ventral lobe 7or sporangiophore7 of ,sphenophyllum4 ,in the latter genus the whorled sporophylls consist in most species of a dorsal and a ventral lobe1 the latter serving as a sporangiophore bearing one or more sporangia2 in ,tmesipteris the sporophylls are spirally disposed and each consists of a bilobed sterile portion bearing a septate sporangium or bilocular synangium on a very short ventral lobe4 ,professor ,bower#bh1 in his account of the development and structure of the sporophylls of ,tmesipteris1 drew attention to the comparatively frequent occurrence of abnormal sporophylls and spoke of the plant as unstable4 ,more recently ,professor ,thomas#bi of ,auckland has carefully examined living plants1 with the result that variations of different kinds are proved to be exceedingly common4 ,he finds that sporophylls occur which exhibit repeated dichotomy of the axis 7fig4 #abj1 ,d1 ,f7 and thus each may bear four instead of two leaf-lobes and three synangia1 one at the first fork and one at each of the forks of the second order#cj4 ,other abnormalities occur in which the synangium is raised on a distinct stalk instead of being more or less sessile at the point from which the leaf-lobes diverge4 ,a third form of departure from the normal is that in which there is no synangium on the bilobed sporophyll1 its place being taken by a leaf-lobe4 ,the deduction from the occurrence of these abnormalities is that the synangium of ,tmesipteris represents a ventral leaf-lobe1 as ,scott suggested4 ,professor ,thomas draws attention to the resemblance between ,tmesipteris sporophylls and the foliage-leaves of ,sphenophyllum1 which are either simple with dichotomously branched veins or the lamina is deeply divided into two or more segments4 ,in some types of ,sphenophyllostachys the bracts are simple 7,s4 ,dawsoni71 but in others 7,sphenophyllum majus1 fig4 #aac1 ,c7 they are forked like the foliage-leaves and bear a close resemblance to the abnormal sporophylls of ,tmesipteris4 ,moreover1 in ,sphenophyllostachys ,rmeri 7fig4 #aac1 ,a7 each ventral lobe of a sporophyll bears two sporangia1 a condition almost identical with that represented by the occasional occurrence of a synangium on a comparatively long stalk in ,tmesipteris4 ,similarly the more elaborate sporophylls of ,cheirostrobus may be compared with the branched sporophylls of ,tmesipteris 7fig4 #abj74 ,this agreement between the sporophylls of the ,palaeozoic and recent genera acquires additional importance from the very close resemblance between the exarch stele of ,sphenophyllum and that of the genus ,psilotum1 which conforms to the ,palaeozoic type not only in the centripetal character of the primary xylem and in its exarch structure1 but also in the occasional occurrence of secondary xylem#ca1 and in the stellate form of its transverse section4 ,the occasional mesarch structure of the stele of ,cheirostrobus finds a parallel in the mesarch xylem groups in the stem of ,tmesipteris4 ,it is thus on the strength of these resemblances that ,thomas and ,bower would remove the ,psilotaceae from the group ,lycopodiales and unite them with ,sphenophyllum and ,cheirostrobus in the ,sphenophyllales4 ,while admitting the validity of the comparison briefly referred to above1 ,i prefer to retain the ,psilotaceae as a division of the ,pteridophyta including only ,psilotum and ,tmesipteris4 ,sidenote3 ,,sphenophyllum ,in his recent book on ,the ,origin of ,land ,flora1 ,prof4 ,bower raises objection to the use of the term ventral lobe in speaking of the sporangium-bearing stalk or sporangiophore borne on the sporophyll of ,sphenophyllum4 ,he points out that the use of this term implies the derivation of the sporangiophore by metamorphosis of part of a vegetative leaf1 an opinion untenable in the absence of proof4 ,the designation sporangiophore is no doubt preferable to that of ventral lobe as it carries with it no admission of particular morphological value2 as a further concession to a non-committal attitude we may provisionally at least regard a sporangiophore as an organ sui generis 8and not the result of modification of any other part#cb40 ,the view put forward by ,prof4 ,lignier#cc that the ,sphenophyllales are descendants of primitive ferns is not convincing1 and his comparison of ,sphenophyllum with ,archaeopteris lacks force in view of our ignorance as to the nature of the reproductive organs of the latter genus4 ,that the ,sphenophyllales are connected with the ,equisetales and with the ,psilotales by important morphological features is clear2 but the comparison between the sporophylls of the extinct genera with those of the existing genus ,tmesipteris1 though helpful and possibly based on true homology1 cannot be considered as settling the morphological value of the sporangiophores of ,sphenophyllum and ,cheirostrobus4 ,i do not propose to discuss at length the different views in regard to the morphological nature of the sporangiophore of ,sphenophyllum4 ,the comparison1 which we owe in the first instance to ,scott1 with the synangium of the ,psilotales with its short stalk1 though not accepted by ,lignier as a comparison based on true homology1 is one which appeals to many botanists and is probably the best so far suggested4 ,the further question1 whether these sporangiophores are to be called foliar or axial structures is one which has been answered by several authors1 but it is improbable that we shall soon arrive at a decision likely to be accepted as final4 ,discussions of this kind tend to assume an exaggerated importance and frequently carry with them the implication that every appendage of the nature of a sporangiophore can be labelled either shoot or leaf4 ,we treat the question from an academic standpoint and run a risk of ignoring the fact that the conception of stem and leaf is based on morphological characteristics1 which have been evolved as the result of gradual differentiation of parts of one originally homogeneous whole4 ,there is much that is attractive in the view recently propounded by ,mr ,tansley that a leaf is not an appendicular organ differing ab initio from the axis on which it is borne1 but that it is in phylogenetic origin a 8branch-system of a primitive undifferentiated sporangium-bearing thallus#cd40 ,admitting the probability that this view is correct1 our faith in the importance of discussions on the morphological nature of sporangiophores is shaken1 and we realise the possibility that our zeal for formality and classification may lead to results inconsistent with an evolutionary standpoint#ce4 ,,chapter ,,xiii4 ,,psilotales4 ,the two recent genera ,psilotum and ,tmesipteris are usually spoken of as members of the family ,psilotaceae which is included as one of the subdivisions of the ,lycopodiales4 ,it is probable1 as ,scott#cf first suggested1 that these two plants are more nearly allied than are any other existing types to the ,palaeozoic genus ,sphenophyllum4 ,we may give expression to the undoubted resemblances between ,tmesipteris and ,psilotum and the ,sphenophyllales by including the recent genera as members of that group1 originally founded on the extinct genus ,sphenophyllum2 this is the course adopted by ,thomas#cg and by ,bower#ch3 or we may emphasise the fact that these two recent genera differ in certain important respects from ,lycopodium and ,selaginella by removing them to a separate group1 the ,psilotales4 ,the latter course is preferred on the ground that the inclusion of ,psilotum and ,tmesipteris in a group founded on an extinct and necessarily imperfectly known type1 is based on insufficient evidence and carries with it an assumption of closer relationship than has been satisfactorily established4 ,the genus ,tmesipteris 7fig4 #abj1 ,a7 is represented by a single species ,t4 tannensis ,bertr4#ci which usually occurs as an epiphyte on the stems of tree-ferns in ,australia1 ,new ,zealand1 and ,polynesia4 ,psilotum1 with two species ,p4 triquetrum ,sw4 7fig4 #aah7 and ,p4 complanatum ,sw41 flourishes in moist tropical regions of both hemispheres1 growing either on soil rich in organic substances or as an epiphyte4 ,both genera are considered to be more or less saprophytic4 ,illustration3 ,,fig4 #aah4 ,psilotum triquetrum 7 natural size74 ,a4 ,synangium4 ,b4 ,sporophyll after removal of the synangium4 7,m4,s47 ,psilotum4 ,the common tropical species ,p4 triquetrum 7fig4 #aah7 is characterised by an underground rhizome which forms a confused mass of dark brown branches covered with filamentous hairs as substitutes for roots and gives off erect repeatedly forked aerial shoots4 ,in ,p4 complanatum#dj the habit is similar to that of the more abundant and better-known species1 but the pendulous shoots are characterised by their broader and flatter form4 ,in both species the function of carbon-assimilation is performed by the outer cortex of the green branches1 as the small size of the widely-separated foliage leaves renders them practically useless as assimilating organs4 ,the sporophylls consist of a short axis terminating in two small divergent forks and bearing on its adaxial surface a trilocular or in rare cases a bilocular synangium 7fig4 #aah1 ,a and ,b74 ,the walls of the loculi are composed of several layers of cells and dehiscence takes place along three lines radiating from the centre of the synangium4 ,professor ,thomas#da has recorded 8fairly numerous instances in ,psilotum of a second dichotomy of one branch of the first fork1 or1 less frequently1 of both branches03 instead of one synangium subtended by the two slender leaflets of the forked sporophyll-axis1 there may be two synangia and three leaf-lobes or three synangia and four leaf-lobes4 ,the occurrence of both these abnormalities in ,psilotum and ,tmesipteris shows a decided tendency in the ,psilotales to a repeated dichotomy of the sporophylls#db4 ,a single stele#dc with a fluted surface occupies the axis of an aerial shoot 7fig4 #aai1 ,a72 the axial region is occupied by a core of elongated mechanical elements 7s71 which may occasionally extend to the periphery of the xylem and break the continuity of the band of scalariform tracheae 7fig4 #aai1 ,a1 a74 ,the tracheae form the arms of an irregularly stellate stele and each arm is terminated by protoxylem elements 7fig4 #aai1 ,b1 px74 ,the rays of the xylem cylinder1 which may be as many as six or eight in the upper part of the aerial shoots1 become reduced in number as the rhizome is approached1 assuming a diarch structure near the junction4 ,in the rhizome the xylem forms an approximately triangular group of tracheae without any core of mechanical elements4 ,three to four layers of parenchyma succeeded externally by an ill-defined phloem 7fig4 #aai1 ,a1 p7 surround the xylem and a fairly distinct endodermis 7fig4 #aai1 ,a and ,b1 e7 encloses the whole4 ,to ,mr ,boodle#dd is due the interesting discovery that in some parts of the rhizome the parenchymatous zone surrounding the scalariform tracheae may become the seat of meristematic activity which results in the production of secondary tracheae often characterised by a sinuous longitudinal course4 ,there is no definite cambium1 but the radially disposed tracheae and the adjacent parenchymatous elements clearly demonstrate the secondary nature of the tissue immediately external to the group of primary xylem4 ,fig4 #aai1 ,c1 drawn from a section kindly supplied by ,mr ,boodle1 shows the secondary xylem elements at x associated with radially disposed thin-walled cells abutting on the primary xylem1 x4 ,it is probable that this added tissue may be a remnant of a more extensive secondary thickening characteristic of the ancestors of the recent species4 ,in their manner of occurrence and sinuous course these secondary tracheids bear a resemblance to the secondary xylem of ,lepidodendron fuliginosum#de4 ,the stele of the aerial shoot bears a fairly close resemblance to the vascular axis of ,cheirostrobus1 and its three-rayed form in the lower portions of the green branches recalls that of the ,sphenophyllum stele1 except that the axial xylem elements of the ,palaeozoic genus are usually represented in ,psilotum by mechanical tissue4 ,the cortex consists of three regions 7fig4 #aai1 ,a71 an outer zone of chlorophyllous tissue 7a7 rich in intercellular spaces succeeded by a band of mechanical tissue 7b7 which gradually passes into an inner region of larger and thinner-walled cells 7c74 ,illustration3 ,,fig4 #aai4 ,a4 ,diagram of transverse section of aerial shoot of ,psilotum triquetrum4 a--c1 cortex2 p1 phloem2 e1 endodermis2 s1 stereome2 x1 xylem2 a1 gap in xylem4 ,b4 ,enlarged view of one of the angles of the xylem shown in ,a4 px1 protoxylem4 ,c4 ,part of transverse section of an approximately triangular rhizome stele showing a portion of the metaxylem x2 px1 protoxylem elements2 x1 secondary xylem4 ,sidenote3 ,,tmesipteris ,the genus ,tmesipteris#df agrees with ,psilotum in general habit and in its epiphytic and probably in some degree saprophytic mode of life4 ,its brown rootless rhizome1 which grows among the roots of tree-ferns or rarely in the ground1 gives off pendulous or erect shoots reaching a length of two feet and bearing lanceolate mucronate leaves #b-c cm4 long 7fig4 #abj1 ,a7 attached by decurrent leaf-bases4 ,the sporophylls1 replacing the upper leaves or occurring in more or less well-defined zones alternating with the foliage leaves1 consist of a short axis terminating in a pair of lanceolate lobes and bearing on its adaxial surface an elongated bilocular synangium attached to a very short stalk 7fig4 #abj1 ,b74 ,reference has already been made to the divergent opinions as to the morphological nature of the sporophylls or sporangiophores1 but recent investigations distinctly favour the view that a sporophyll is best interpreted as a stalked leaf with two sterile laminae and an almost sessile1 or in some cases a more obviously stalked1 synangium2 the whole sporophyll is characterised by the possession of a ventral and a dorsal lobe#dg4 ,the drawings reproduced in fig4 #abj1 ,d and ,f1 illustrate some of the frequent variations described by ,thomas in plants which he observed in the ,new ,zealand forests4 ,the sporophyll shown in fig4 #abj1 ,d and ,f1 has branched twice and bears three synangia4 ,illustration3 ,,fig4 #abj4 ,tmesipteris4 ,a4 ,foliage leaves4 ,b4 ,sporophyll and bilocular synangium4 ,c4 ,diagram of transverse section of stele4 px1 protoxylem4 ,d1 ,f4 ,abnormal sporophylls4 7,from drawings made by ,prof4 ,thomas and generously placed at my disposal4 ,a4,c4,s47 ,e4 ,portion of ,c enlarged4 ,the aerial branches of ,tmesipteris possess a central cylinder of separate xylem groups in which the protoxylem occupies an internal position 7fig4 #abj1 ,c and ,e1 px7 enclosing an axial parenchymatous region4 ,the cells of a few layers of the inner cortex immediately outside the endodermis are rendered conspicuous by a dark brown deposit4 ,the cortex as a whole is composed of uniform parenchymatous tissue4 ,in the lower part of the aerial shoots and in the rhizome the xylem forms a solid strand without protoxylem elements and conforms more clearly to that of ,psilotum4 ,in this short account of the anatomy of ,tmesipteris no mention is made of the effect produced on the stele by the departure of leaf-traces and of vascular stands to supply branches4 ,miss ,sykes#dh in a recently published paper on the genus has shown that the exit of a leaf-trace does not break the continuity of the xylem of the stele1 while the exit of a sporophyll-trace is marked by an obvious gap4 ,evidence is adduced in support of the conclusion that this difference1 which at first sight appears to be one of morphological importance1 is in reality merely a question of degree and 8is due to the earlier preparation for the formation of #8sporophyll' than leaf-traces40 ,miss ,sykes gives her adherence to the view that the 8sporophylls0 of ,tmesipteris are branches and not leaves1 but despite the arguments advanced this interpretation seems to me less probable than that which recognises the sporophyll as a foliar organ4 ,prof4 ,lignier#di has pointed out that if ,miss ,sykes's conclusion as to the axial nature of the sporophyll in ,tmesipteris is accepted1 it diminishes the force of the comparison between the sporophylls of that genus and ,sphenophyllum as those of the latter can hardly be regarded as other than foliar organs4 ,both members of the ,psilotales may1 as ,boodle has suggested1 be regarded as descendants of a common parent in which the aerial stems possessed a fluted or stellate cylinder of mesarch xylem4 ,there can be no doubt as to the significance of the morphological resemblances between the ,psilotales and the genera ,sphenophyllum and ,cheirostrobus1 but the position of ,tmesipteris and ,psilotum in the plant-kingdom may probably be best expressed by adopting the group-name ,psilotales rather than by transferring the recent genera to the ,sphenophyllales4 ,one of the most striking differences between the ,psilotales and the genus ,lycopodium is in the form of the sporophylls and sporangia2 in ,lycopodium a single sporophyll bears a unilocular sporangium1 but in the ,psilotales the sporophyll may be described as a bilobed structure homologous with a foliage-leaf1 bearing a sporangiophore which consists of a short stalk terminating in a bilocular or trilocular synangium2 the short stalk receives a special branch from the vascular bundle of the sterile portion of the sporophyll#ej4 ,fossils described by authors as being closely allied to ,psilotum4 ,a search through palaeobotanical literature reveals the existence of a very small number of specimens which have been identified as representatives of the ,psilotales4 ,an inspection of the material or published drawings leads one to the conclusion that practically no information of a satisfactory kind is available in regard to the past history of the two southern genera ,psilotum and ,tmesipteris1 which are regarded by some botanists as relics of an ancient branch#ea of pteridophytes4 ,sidenote3 ,,psilotites1 ,,etc4 ,in #ahdb ,mnster#eb instituted the genus ,psilotites for a small impression of a slender branched axis from ,jurassic rocks near ,mannheim in ,germany which he named ,psilotites filiformis2 ,schimper#ec spoke of the specimens as too doubtful for determination1 an opinion with which every botanist would cordially agree4 ,goldenberg's species ,psilotites lithanthracis#ed from the ,saarbrcken coal-field is founded on impressions of axes3 some of these are dichotomously branched and bear small oval projections1 which may be rudimentary leaves or possibly leaf-scars4 ,more recently ,kidston#ee described specimens of branched axes from the ,lanarkshire coal-field bearing a row of lateral thorn-like projections under the title ,psilotites unilateralis2 but these fragments1 as ,dr ,kidston himself admits1 are of no botanical value4 ,in a paper on fossil ,salvinias1 ,hollick#ef mentions ,salvinia reticulata1 originally described by ,heer and by ,ettingshausen and ,s4 ,alleni ,lesq4#eg a ,tertiary species1 and calls attention to their very close resemblance in form1 nervation1 and apex to the leaves of the genus ,tmesipteris3 he refers both species to that genus4 ,the drawings reproduced by ,hollick represent leaves with a midrib and numerous anastomosing lateral veins1 whereas in ,tmesipteris the lamina of the leaf has a midrib without lateral branches4 ,an enlarged drawing of the outlines of the epidermal cells would correspond closely with the small reticulations in the fossil leaves and it may be that there has been some confusion between veins and cell-outlines4 ,in any case there would seem to be no reason for the use of the recent generic name#eh4 ,among other fossils assigned to the ,psilotales we have ,marion's genus ,gomphostrobus from the ,permian of ,france and ,germany#ei4 ,marion placed this plant in the ,coniferales on the strength of its resemblance to ,walchia and ,araucaria1 but ,potoni#fj is inclined to recognise in the leaves and monospermic sporophylls characters suggestive of ,lycopodiaceous affinity4 ,the latter author in #ahiafa1 in ignorance of ,marion's proposal to adopt the name ,gomphostrobus1 instituted a genus ,psilotiphyllum for the sporophylls of a species originally described by ,geinitz#fb as ,sigillariostrobus bifidus1 but he subsequently adopted ,marion's designation and with some hesitation included the ,french and ,german specimens in the ,psilotales4 ,as stated elsewhere#fc1 ,potoni's arguments in favour of his view hardly carry conviction1 and it is probably more in accordance with truth to deal with ,gomphostrobus in the chapter devoted to the ,coniferales4 ,psilophyton4 ,the generic title ,psilophyton1 instituted by the late ,sir ,william ,dawson#fd1 has become familiar to geologists as that of a ,pre-,carboniferous plant characteristic of ,devonian and ,silurian rocks in ,canada1 the ,united ,states of ,america1 and ,europe4 ,from the botanist's point of view the name stands for miscellaneous remains of plants of different types and in many cases unworthy of record4 ,the genus was founded on impressions of branched axes from the ,devonian strata of ,new ,brunswick resembling the rachis and portions of lateral pinnae of ferns or the forked slender twigs of a ,lycopod4 ,the type-species ,psilophyton princeps ,daws4 as represented on somewhat slender evidence in ,dawson's restoration1 which accompanies the original description of the genus and has since been copied by several authors1 is characterised by the possession of a horizontal rhizome bearing numerous rootlets and giving off dichotomously branched aerial shoots with spinous appendages1 compared with rudimentary leaves1 and terminating in slender branchlets bearing pendulous oval 8spore-cases0 from their tips4 ,some of the branchlets exhibit a fern-like vernation4 ,the plant is spoken of by ,dawson as apparently a generalised type#fe1 resembling in habit and in its rudimentary leaves the recent genus ,psilotum and presenting points of contact with ferns4 ,specimens were found in an imperfectly petrified state showing a central cylinder of scalariform tracheae surrounded by a broad cortical zone of parenchyma and fibrous tissue4 ,among other species described by the author of the genus we need only mention ,psilophyton robustius1 characterised by vegetative shoots and 8spore-cases0 similar to those of the type-species2 but1 as ,solms-,laubach#ff has pointed out1 the petrified sections referred by ,dawson to ,p4 robustius are of an entirely different anatomical type from that of ,p4 princeps#fg4 ,british fossils from the ,old ,red ,sandstone from the north of ,scotland1 ,orkney and ,caithness1 originally figured by ,hugh ,miller and compared by him with algae but more especially with recent ,lycopods1 were subsequently placed by ,carruthers#fh in the genus ,psilophyton as ,p4 ,dechianum1 the specific designation being chosen on the ground that the ,scotch specimens are specifically identical with fossils described by ,goeppert#fi as ,haliserites ,dechianus4 ,various opinions have been expressed in regard to the nature of the ,devonian species ,haliserites ,dechianus ,goepp4 with which ,carruthers#gj identified ,miller's ,old ,red ,sandstone plant3 reference may be made to a paper by ,white#ga containing figures of dichotomously branched impressions described as species of ,thamnocladus which he includes among the algae4 ,in describing some ,belgian impressions of ,devonian age as ,lepidodendron gaspianum ,daws4 ,crpin#gb states that ,carruthers has come to regard the specimens named by him ,psilophyton ,dechianum as branches of a ,lepidodendron2 he also quotes ,carruthers as having expressed the opinion that the name ,psilophyton had been employed by ,dawson for two kinds of fossils1 some being twigs of ,lepidodendron while others1 identified by ,dawson as the reproductive branches of species of ,psilophyton1 represent the spore-cases of ferns comparable with ,stur's genus ,rhodea#gc4 ,one of the examples figured by ,carruthers#gd as ,p4 ,dechianum from ,thurso 7preserved in the ,british ,museum1 no4 #ebfcf71 measuring #cd cm4 in length and #h mm4 broad1 bears a close resemblance to a fern rhizome covered with ramental scales such as that of a species of ,davallia4 ,other ,belgian specimens described by ,gilkinet#ge as ,lepidodendron burnotense1 like ,crpin's species1 are no doubt generically identical with some of the ,scotch and ,canadian fossils placed in the genus ,psilophyton1 though ,penhallow#gf considers that the species ,lycopodites ,milleri is more correctly referred to ,lycopodites than to ,psilophyton4 ,a more recent paper on the ,geology of the ,perry basin in ,south-eastern ,maine by ,smith and ,white#gg contains a critical summary of the literature on ,psilophyton and drawings of specimens4 ,the latter afford good examples of ,pre-,carboniferous plant fragments1 such as are often met with in various parts of the world1 which conform in habit to the ,new ,brunswick specimens made by ,dawson the type of his genus4 ,an examination of material in the ,montreal ,museum and of ,hugh ,miller's specimens in the ,edinburgh collection leads me to share the opinion of ,count ,solms-,laubach that the name ,psilophyton has been applied to plants which should not be included under one generic title4 ,as ,kidston#gh pointed out1 the ,canadian species ,psilophyton robustius is not generically distinct from ,british and ,belgian specimens referred to ,lepidodendron2 it may possibly be identical with the ,bohemian plants on which ,stur founded his genus ,hostinella#gi4 ,the ,devonian plants described by ,stur have since been examined by ,jahn#hj who regards them as vascular plants1 and not as algae to which ,stur referred them2 he mentions two species of ,psilophyton but gives no figures4 ,the 8spore-cases0 of ,dawson may be found to be the microsporangia or perhaps the small seeds of some pteridosperm2 the forked axes with a smooth surface and others figured by ,miller and by ,dawson1 with the surface covered with scales suggesting the ramenta of a fern1 may be the rachises or rhizomes of filicinean plants4 ,other specimens may be ,lepidodendron twigs1 as for example the petrified fragments figured by ,dawson as ,psilophyton princeps2 while the stem identified as ,p4 robustius is most probably that of a ,gymnosperm4 ,it is doubtful whether a useful purpose is served by retaining the genus ,psilophyton4 ,it was in the first instance instituted on the assumption1 which cannot be upheld1 that the abundant material in the ,new ,brunswick beds bore a sufficiently close resemblance to the rhizome and aerial branches of ,psilotum4 ,psilophyton has served as a name for miscellaneous plant fragments1 many of which are indeterminable4 ,dr ,white concludes his account of the genus with the following words#ha3 8,the examination of such so-called ,psilophyton material as ,i have seen shows the existence in ,america of two or more groups1 represented by several fairly well-marked species which possess stratigraphical value1 and which should be carefully diagnosed and illustrated4 ,it is probable also that additional material throwing light on the structure and relationships of these very remarkable early types of land-plants will be discovered at some locality4 ,the inspection of the material in hand emphasises the need1 as was pointed out by ,solms-,laubach1 for the revision of the material referred by various authors to ,psilophyton1 together with a thorough re-examination and re-publication of the types40 ,until a thorough re-examination has been made of the ,canadian material1 with a view to determine whether there exist substantial reasons for the retention of ,dawson's genus1 it is undesirable to continue to make use of this name for ,pre-,carboniferous fossils which are too incomplete to be assigned with certainty to a definite group of plants4 ,dr ,white draws attention to the similarity of some of the ,perry basin specimens to ,nathorst's genus ,cephalotheca#hb from ,devonian rocks of ,bear ,island in the ,arctic regions1 a comparison which might be extended to other genera and which serves to illustrate the possibility that many of the specimens labelled ,psilophyton may eventually be recognised as examples of well defined generic types belonging to more than one group of plants4 ,,chapter ,,xiv4 ,,lycopodiales4 ,the recent members of the ,lycopodiales are considered apart from the extinct genera in order that our examination of the latter may be facilitated by a knowledge of the salient characteristics of the surviving types of this important section of the ,pteridophyta4 ,a general acquaintance with the extinct as well as with the recent genera will enable us to appreciate the contrasts between the living and the fossil forms and to realise the prominent position occupied by this group in the ,palaeozoic period1 a position in striking contrast to the part played by the diminutive survivors in the vegetation of the present day4 ,in the account of the recent genera special attention is drawn to such features as afford a clue to the interpretation of the fossils1 and the point of view adopted1 which at times may appear to lead to an excessive attention to details1 is necessarily somewhat different from that represented in botanical text-books#hc4 ,a4 ,,homosporeae4 ,lycopodiaceae3 genera ,phylloglossum1 ,lycopodium4 ,b4 ,,heterosporeae4 ,selaginellaceae3 genus ,selaginella4 ,isoetaceae3 genus ,isoetes4 ,the existing plants included in the ,lycopodiales are in nearly all cases perennial herbaceous pteridophytes1 exhibiting in their life-histories a well marked alternation of generations4 ,the sporophyte 7asexual generation7 is characterised by the relatively small size of the leaves except in the genus ,isoetes 7fig4 #acb7 and in the ,australian and ,new ,zealand genus ,phylloglossum4 ,the stems are usually erect or trailing1 pendulous in epiphytic species or small and tuberous in ,isoetes and ,phylloglossum4 ,the repeated forking of the shoots 7monopodial and dichotomous branching7 is a prominent feature of the group4 ,the vascular tissue of the stem usually assumes the form of a single axial strand 7stele7 7fig4 #abe71 but the shoots of some species of ,selaginella often contain two or more distinct steles 7fig4 #aca74 ,the group as a whole is characterised by the centripetal development of the xylem composed almost entirely of scalariform tracheids3 secondary xylem and phloem of a peculiar type occur in ,isoetes1 and the production of secondary xylem elements in a very slight degree has been noticed in one species of ,selaginella 7,s4 spinosa7#hd4 ,the roots are constructed on a simple plan1 having in most cases only one strand of spiral protoxylem elements 7monarch structure74 ,in ,lycopodium1 in which stem and root anatomy are more nearly of the same type than in the majority of plants1 several protoxylem strands may be present4 ,the sporangia are axillary or1 more frequently1 borne on the upper surface of sporophylls1 which are either identical with or more or less distinct from the foliage leaves2 in the latter case the sporophylls often occur in the form of a well defined strobilus 7cone7 at the tips of branches4 ,the gametophyte 7sexual generation7 is represented by prothalli which1 in the homosporous genera1 may live underground as saprophytes1 or the upper portion may develop chlorophyll and project above the surface of the ground as an irregularly lobed green structure 7e4g4 ,lycopodium cernuum7#he4 ,in the heterosporous forms the prothalli are much reduced and do not lead an independent existence outside the spore by the membrane of which they are always more or less enclosed4 ,the sexual organs are represented by antheridia and archegonia2 the male cells are provided with two cilia except in ,isoetes which has multiciliate antherozoids like those of the ferns4 ,the existing ,lycopods1 though widely distributed1 never grow in sufficiently dense masses to the exclusion of other plants to form a conspicuous feature in the vegetation of a country4 ,the inconspicuous rle which they play among the plant-associations of the present era affords a striking contrast to the abundance of the arborescent species in the ,palaeozoic forests of the northern hemisphere4 ,lycopodiaceae4 ,lycopodium1 represented by nearly #ajj species1 forms a constituent of most floras3 epiphytic species predominate in tropical regions1 while others flourish on the mountains and moorlands of ,britain and in other extra-tropical countries4 ,for the most part ,lycopodium exhibits a preference for a moist climate and appears to be well adapted to habitats where the amount of sunlight is relatively small and the conditions of life unfavourable for dense vegetation4 ,mountains and islands constantly recur as situations from which species have been recorded4 ,some species are essentially swamp-plants1 e4g4 ,lycopodium inundatum1 a ,british species1 and ,l4 cruentum from the marshes of ,sierra ,nevada4 ,a variety of the ,american species1 ,l4 alopecuroides 7var4 aquaticum7 affords an instance of a submerged form1 which has been collected from an altitude of #ab-ad1jjj ft4 on the ,andes and ,himalayas4 ,it is noteworthy that a considerable variety of habitats is represented within the limits of the genus and that many species are sufficiently hardy to exist in circumstances which would be intolerable to the majority of flowering plants#hf4 ,the ,british species frequently spoken of as ,club ,mosses1 include ,lycopodium ,selago1 ,l4 annotinum1 ,l4 clavatum1 ,l4 alpinum1 and ,l4 inundatum4 ,selaginellaceae4 ,the species of ,selaginella1 over #cjj in number1 are widely spread in tropical and subtropical forests1 growing on the ground with trailing1 suberect or erect stems climbing over taller and stouter plants or as pendulous epiphytes on forest trees4 ,selaginella lepidophylla1 a tropical ,american type1 popularly known as the ,resurrection plant1 and often erroneously spoken of as the ,rose of ,jericho#hg1 possesses the power of rolling up its shoots during periods of drought and furnishes an example of a species adapted to conditions in marked contrast to those which are most favourable to the majority of species4 ,the only ,british species is ,selaginella spinosa named by ,linnaeus ,lycopodium selaginoides and occasionally referred to as ,selaginella spinulosa ,a4 ,br4 7not to be confounded with a ,javan species ,s4 spinulosa ,spring#hh74 ,isoetaceae4 ,isoetes 7fig4 #acb71 of which ,mr ,baker in his ,handbook of the ,fern-,allies enumerates #di species1 is a type apart1 differing in habit as in certain other characters from the other members of the ,lycopodiales4 ,some botanists#hi prefer to include the genus among the ,filicales1 but the balance of evidence1 including resemblances between ,isoetes and extinct ,lycopodiaceous plants1 would seem to favour its retention as an aberrant genus of the group ,lycopodiales4 ,some species are permanently submerged1 others occur in situations intermittently covered with water1 and a few grow in damp soil4 ,isoetes lacustris is found in mountain tarns and lakes of ,britain and elsewhere in ,central and ,northern ,europe and ,north ,america4 ,isoetes hystrix#ij1 a land-form occurs in ,guernsey1 ,north-,east ,france1 ,spain and ,asia ,minor4 ,lycopodiaceae4 ,the monotypic genus ,phylloglossum1 represented by ,p4 ,drummondii of ,australia and ,new ,zealand1 though interesting from the point of view of its probable claim to be considered the most primitive type of existing ,lycopodiaceous plants1 need not be dealt with in detail4 ,a complete individual1 which does not exceed #d or #e cm4 in length1 consists of a very small tubercle or protocorm bearing a rosette of slender subulate leaves and prolonged distally as a simple naked axis which overtops the foliage leaves and terminates in a compact cluster of small scale-like sporophylls1 each subtending a single sporangium#ia4 ,lycopodium4 ,it would be out of place in a volume devoted mainly to fossil plants to attempt a comprehensive account of the general morphology of recent species1 and indeed our knowledge of the anatomical characters of the genus is still somewhat meagre4 ,for purposes of comparison with extinct types1 it is essential that some of the more important morphological features of existing species should be briefly considered4 ,the additions made to our knowledge of the gameophyte#ib of ,european and tropical species during the last two decades have revealed a striking diversity in habit4 ,in several species1 grouped round the widely distributed type ,lycopodium ,selago ,linn41 the comparatively short1 erect or suberect1 shoots form fairly compact tufts2 the ordinary foliage-leaves function as sporophylls1 and the sporangia are not localised on special portions of shoots4 ,from this type1 we pass to others in which the fertile leaves tend to be confined to the tips of branches1 but hardly differ in form from the sterile4 ,a further degree of specialisation is exhibited by species with well-defined cones composed of leaves 7or bracts71 the primary function of which is to bear sporangia and to afford a protective covering to the strobilus#ic4 ,lycopodium rufescens ,hook4 ,an ,andian species with stout dichotomously branched erect stems bears on the younger shoots crowded leaves with their thick and broadly triangular laminae pointing upwards1 but on the older and thick shoots the laminae are strongly reflexed 7fig4 #aba1 ,a74 ,the lower part of the specimen represented in fig4 #aba1 ,a1 shows tangentially elongated scars and persistent leaf-bases or cushions left on the stem after the removal of the free portions of the leathery leaves1 a surface-feature which also characterises the ,palaeozoic genus ,lepidodendron4 ,the reflexed leaves and persistent leaf-cushions are clearly seen in the piece of old stem of ,lycopodium dichotomum ,jacq41 a tropical ,american species reproduced in fig4 #aba1 ,b4 ,such species as ,l4 erythraeum ,spring1 and others with stiff lanceolate leaves exhibit a striking resemblance to the more slender shoots of some recent conifers1 more especially ,araucaria excelsa1 ,a4 ,balansae1 ,cryptomeria1 ,dacrydium and other genera4 ,illustration3 ,,fig4 #aba4 ,lycopodium4 ,a4 ,lycopodium rufescens4 ,b4 ,l4 dichotomum4 ,c4 ,l4 tetragonum4 ,d4 ,l4 nummularifolium4 ,e4 ,l4 ,dalhousianum4 ,f4 ,l4 casuarinoides4 ,g4 ,l4 volubile4 7,from specimens in the ,cambridge ,herbarium and ,botanic ,garden4 ,m4,s47 ,illustration3 ,,fig4 #abb4 ,lycopodium squarrosum4 ,the branches of the larger shoot terminate in cones4 7,from a plant in the ,cambridge ,botanic ,garden4 ,reduced47 ,in ,lycopodium tetragonum ,hook41 7fig4 #aba1 ,c71 a species from the ,alpine region of the ,andes1 the long1 pendulous and repeatedly forked branches bear four rows of fleshy ovate leaves and simulate the vegetative characters of certain conifers4 ,sidenote3 ,,lycopodium ,illustration3 ,,fig4 #abc4 ,lycopodium cernuum4 7,from a specimen in the ,cambridge ,herbarium4 nat4 size47 ,l4 squarrosum ,forst4 7fig4 #abb7 a tropical species from ,india1 ,polynesia1 and other regions1 is characterised by its stout stems reaching a diameter of #be cm41 bearing long pendulous branches with large terminal cones composed of sporophylls differing but slightly from the foliage leaves4 ,the plant represented in the photograph serves as a good illustration of the practical identity in habit between ,palaeozoic and recent genera4 ,illustration3 ,,fig4 #abd4 ,lycopodium obscurum4 ,l4 ,dalhousianum ,spring1 from the mountains of the ,malay ,peninsula and ,borneo1 has larger leaves of finer texture with a distinct midrib reaching a length of #b-c cm4 7fig4 #aba1 ,e74 ,another type is illustrated by ,l4 nummularifolium ,blume1 also a ,malayan species1 in which the leaves are shorter1 broadly oblong or suborbicular1 and the branches terminate in narrow and often very long strobili 7sometimes reaching a length of #cj cm47 with small bracts in striking contrast to the foliage leaves 7fig4 #aba1 ,d74 ,a similar form of long and slender strobilus occurs in ,l4 ,phlegmaria ,linn41 a common tropical ,lycopod3 the frequent forking of the strobili noticed in this and other species is a character not unknown among fossil cones 7,lepidostrobi74 ,l4 cernuum ,linn4 7fig4 #abc71 another widely spread tropical type1 offers an even closer resemblance than ,l4 squarrosum to the fossil ,lepidodendra4 ,the stiff erect stem1 reaching in some cases a length of several feet1 bears numerous repeatedly forked branches1 with crowded linear leaves1 terminating in short cylindrical cones with broadly ovate sporophylls4 ,a similar habit characterises the ,north ,american species ,l4 obscurum ,linn4 7fig4 #abd7 bearing cones several centimetres in length4 ,l4 casuarinoides ,spring 7fig4 #aba1 ,f7 an eastern tropical species1 is worthy of notice as exhibiting a peculiar form of leaf consisting of a very small lamina1 #c mm4 in length1 borne on the top of a long decurrent base1 which forms a narrow type of leaf-cushion1 bearing some resemblance to the long and rib-like cushions of certain species of ,sigillaria1 and recalling the habit of slender fossil twigs referred to the ,coniferae under such names as ,widdringtonites1 ,cyparissidium1 ,sphenolepidium4 ,l4 volubile ,forst4 7fig4 #aba1 ,g7 a ,new ,zealand species1 in habit and leaf-form bears a close resemblance to the ,jurassic ,lycopodites falcatus ,lind4 and ,hutt4 7fig4 #acg73 it is also a representative of a few species of ,lycopodium which agree with the majority of species of ,selaginella in having two kinds of sterile leaves1 comparatively long falcate leaves forming two lateral rows and smaller appressed leaves on the upper surface of the branches4 ,these examples suffice to illustrate the general appearance presented by the vegetative shoots of recent species of which the foliage leaves vary considerably--from the small scale-leaves of ,lycopodium tetragonum1 to the very slender linear subulate leaves of such a species as ,l4 verticillatum ,linn4 or the long and broader lamina of ,l4 ,dalhousianum 7fig4 #aba1 ,e74 ,it is obvious that fragments of the various types preserved as fossils might well be mistaken either for some of the larger mosses or for twigs of conifers4 ,as ,dr ,bommer#id has pointed out in his interesting paper on 8,les causes d'erreur dans l'tude des empreintes vgtales0 some dicotyledonous plants may also simulate the habit of ,lycopods3 he cites ,phyllachne clavigera ,hook 7,candolleaceae71 ,tafalla graveolens ,wedd 7,compositae7 and ,lavoisiera lycopodioides ,gard4 7,melastomataceae74 ,another point illustrated by fig4 #aba is the close agreement in habit and in the form of the leaves and leaf-cushions between the recent plants and the ,palaeozoic ,lepidodendreae4 ,in his masterly essay 8,on the vegetation of the ,carboniferous ,period1 as compared with that of the present day0 ,sir ,joseph ,hooker called attention to the variation in the shape and arrangement of the leaves in the same species of ,lycopodium4 ,the three woodcuts which he publishes of ,lycopodium densum1 a ,new ,zealand species1 afford striking examples of the diversity in habit and leaf-form and justify his warning 8that if the species of ,lepidodendron were as prone to vary in the foliage as are those of ,lycopodium1 our available means for distinguishing them are wholly insufficient#ie40 ,as we have already noticed1 there is a considerable diversity among recent species1 both as regards habitat and habit2 in the anatomy of the stem also corresponding variations occur within the limits of a well-defined generic type of stele4 ,in species with creeping stems1 such as ,l4 clavatum#if1 the stele exhibits an arrangement of vascular tissue characteristic of the plagiotropic forms4 ,the xylem consists of more or less horizontal plates of scalariform tracheae1 each surrounded by small-celled parenchyma1 alternating with bands or groups of somewhat ill-defined phloem4 ,the protoxylem and protophloem elements occupy an external position 7exarch71 pointing to a centripetal development of the metaxylem4 ,this centripetal or root-like character of the primary xylem is an important feature in recent as in fossil ,lycopods4 ,the close agreement between the roots and stems of recent species in the disposition of the vascular elements also denotes a simpler type of anatomy than occurs in the majority of vascular plants in which stem and root have more pronounced structural peculiarities4 ,a pericycle1 #b-f cells in breadth1 encloses the xylem and phloem bands and this is succeeded by an endodermis1 #b-c cells broad1 with vaguely defined limits4 ,in ,l4 clavatum1 as in ,l4 alpinum1 another ,british species1 the broad cortex is differentiated into three fairly distinct regions2 abutting on the endodermis is a zone several layers broad of thick-walled cells constituting an inner cortex modified for protection and support2 the central region consists of larger and thinner-walled cells adapted for water-storage and aeration2 beyond this is an outer cortical zone of firmer and thicker elements4 ,the prominent leaf-bases or leaf-cushions 7fig4 #abe1 ,a1 lc7 give to the surface of a transverse section a characteristic appearance which presents the closest agreement with that of the younger shoots of ,lepidodendron4 ,from the peripheral protoxylem groups small strands of xylem are given off1 which follow a steeply ascending course through the cortex to the single-veined leaves4 ,the leaf-traces1 in several species at least1 are characterised by a mesarch structure 7fig4 #abe1 ,f1 ,g71 the spiral protoxylem elements occupying an approximately central position4 ,the mesophyll of the leaves varies in regard to the extent of differentiation into a palisade and spongy parenchyma2 in all cases there is a single vascular bundle occasionally accompanied by a secretory duct4 ,illustration3 ,,fig4 #abe4 ,a4 ,lycopodium dichotomum4 ,transverse section of stem3 lc1 leaf-cushion2 lt1 leaf-trace2 ,r1 roots4 ,b4 ,l4 cernuum1 portion of cortex of fig4 ,h1 enlarged4 ,c4 ,l4 saururus4 ,cortex3 lt1 leaf-trace2 a1 thin-walled tissue2 b1 thick-walled tissue2 lc1 lacuna4 ,d4 ,l4 saururus4 ,stele3 x1 xylem2 p1 phloem4 ,e4 ,portion of fig4 ,d1 enlarged3 px1 protoxylem2 p1 phloem4 ,f4 ,transverse section of leaf of ,lycopodium4 ,g4 ,vascular bundle of leaf3 px1 protoxylem4 ,h4 ,l4 cernuum3 b1 branch of stele2 c-c1 cortex2 s1 space in cortex2 lt1 leaf-trace4 ,i4 ,stele of fig4 ,h1 enlarged 7phloem omitted74 ,in erect stems of ,lycopodium1 as represented by ,l4 cernuum 7figs4 #abc1 #abe1 ,h1 ,i71 ,l4 ,dalhousianum1 ,l4 squarrosum 7fig4 #abb7 and many others1 the stele presents a characteristic appearance due to the xylem plates being broken up into detached groups or short uniseriate bands with the interspaces occupied by phloem islands4 ,this type of structure bears a superficial resemblance to that in the single stele of certain species of the fern ,lygodium#ig1 but it is distinguished by the islands of phloem scattered through the stele4 ,in other species the xylem tends to assume the form of a ,maltese cross 7e4g4 ,l4 serratum ,thbg47 or it may be disposed as ,v-shaped and sinuous bands terminating in broad truncate ends composed of protoxylem elements4 ,this form of the xylem and the distribution of the phloem groups are shown in fig4 #abe1 ,d1 ,e1 drawn from a section of a plant of ,lycopodium saururus ,lam4#ih collected by ,mr ,a4 ,w4 ,hill at an altitude of #ae1jjj feet on the ,andes of ,peru4 ,the position of the protoxylem is shown fig4 #abe1 ,e1 px4 ,while several species possess a cortex of three distinct zones 7fig4 #abe1 ,h1 c1 c1 c71 in others the extra-stelar tissue is much more homogeneous1 consisting of thin-walled parenchyma or in some cases of thick-walled elements2 as a general rule1 however1 there is a tendency towards a more compact arrangement in the inner and outer portions of the cortex as contrasted with the larger and more loosely connected cells of the middle region4 ,in certain types the middle cortex contains fairly large spaces1 as in the swamp-species ,l4 inundatum1 which with ,l4 alopecuroides exhibits another feature of some interest first described by ,hegelmaier#ii4 ,if a transverse section of the stem of ,l4 inundatum be examined the leaf-traces are seen to be accompanied by a circular canal containing mucilage which extends into the lamina of the leaf4 ,in a specimen of ,l4 cernuum#ajj obtained at a height of #bejj ft4 by ,professor ,stanley ,gardiner in the ,fiji ,islands1 the leaf-traces 7fig4 #abe1 ,b lt7 were found to be accompanied for part of their course by a well-marked secretory space 7fig4 #abe1 ,b1 s74 ,there is little doubt that the presence of these mucilage canals is directly connected with a certain type of habitat#aja and attention is called to them in view of a resemblance which they offer to a characteristic strand of tissue1 known as the parichnos1 which is associated with the leaf-traces of ,lepidodendreae and ,sigillarieae4 ,in the section shown in fig4 #abe1 ,h1 the xylem of the stele forms more continuous bands than is often the case in ,l4 cernuum which has already been described as having its xylem in small detached groups4 ,the presence of the smaller branch-stele 7fig4 #abe1 ,h1 b7 affords an example of monopodial branching4 ,the outer cortex of ,l4 saururus 7fig4 #abe1 ,c7 exhibits a somewhat unusual feature in the distribution of the thicker-walled tissue 7b7 which encloses a patch of more delicate parenchyma 7a7 with large lacunae 7lc7 in the region of the leaf-bases1 and presents the appearance of an irregular reticulum4 ,this arrangement of the mechanical tissue in the outer cortex is comparable with that in stems of some species of ,sigillaria4 ,in certain species of ,lycopodium the roots#ajb1 which arise endogenously from the axial vascular cylinder1 instead of passing through the cortex of the stem by the shortest route1 bend downwards and bore their way in a more or less vertical direction before emerging at or near the base of the aerial shoot4 ,the transverse section of ,l4 dichotomum represented in fig4 #abe1 ,a1 shows several roots 7,r7 in the cortex2 they consist of a xylem strand of circular or crescentric form accompanied by phloem and enclosed by several layers of root-cortex4 ,the roots of ,lycopodium do not always present so simple a structure as those of ,l4 dichotomum2 the xylem may have an irregularly stellate form with as many as ten protoxylem groups4 ,reproductive ,shoots#ajc4 ,in ,lycopodium ,selago the foliage leaves serve also as sporophylls and1 as ,professor ,bower#ajd has pointed out1 the branches exhibit to some extent a zonal alternation of sterile and fertile leaves2 in other species1 in which foliage leaves and sporophylls are practically identical1 the sporangia occur sporadically on the ordinary leaves4 ,in species with well-defined terminal cones the lower sporophylls may bear arrested sporangia and thus form transitional stages between sterile and fertile leaves1 a feature which occurs also in the male and female flowers of many recent ,araucarieae#aje4 ,the sporangia#ajf 7fig4 #abf1 ,d1 ,f7 are usually reniform and compressed in a direction parallel to the surface of the cone-scales2 they are developed from the upper surface and close to the base of the fertile leaf to which they are attached by a short and thick stalk 7e4g4 ,l4 inundatum7 or by a longer and more slender pedicel 7,l4 ,phlegmaria1 fig4 #abf1 ,e74 ,on maturity the sporangia open as two valves in the plane of compression and the line of dehiscence is determined in some species at least by the occurrence of smaller cells in the wall4 ,in transverse sections of cones in which the sporangia are strongly saddle-shaped1 the sporophylls may appear to bear two sporangia4 ,this is well shown in the section of a cone of ,l4 clavatum shown in fig4 #abf1 ,f4 ,the sporangia a and b are cut through in an approximately median plane showing the irregular outline of the sterile pad 7p7 of tissue in the sporogenous cavity4 ,those at c and d have been traversed at a lower level and the two lobes of the saddle-shaped sporangia are cut below the attachment to the sporophyll4 ,the distal laminae of the sporophylls1 cut at different levels1 are seen at the periphery of the cone4 ,illustration3 ,,fig4 #abf4 ,a4 ,lycopodium cernuum1 longitudinal section of strobilus2 a1 band of lignified cells4 ,b4 ,l4 cernuum4 ,cell from sporangium wall4 ,c4 ,l4 cernuum4 ,sporophyll and sporangium2 lt1 vascular bundle4 ,d4 ,l4 clavatum4 ,part of radial longitudinal section of strobilus2 p1 sterile tissue4 ,e4 ,l4 ,phlegmaria4 ,sporophyll and stalked sporangium4 ,f4 ,l4 clavatum4 ,transverse section of strobilus2 p1 sterile pad4 ,in longitudinal radial section of some cones the sporangia appear to occupy an axillary position1 but in others 7e4g4 ,l4 clavatum7 they are attached to the horizontal portion of the sporophyll almost midway between the axis of the cone and the upturned distal end of the sporophyll 7fig4 #abf1 ,d74 ,the wall of a sporangium frequently consists of #b-c cell-layers and in some cases 7e4g4 ,l4 dichotomum71 it may reach a thickness of seven layers1 resembling in this respect the more bulky sporangia of a certain type of ,lepidodendroid cone4 ,the sporogenous tissue is separated from the stalk of the sporangium by a mass of parenchymatous tissue which may project as a prominent pad 7fig4 #abf1 ,d1 ,f1 p7 into the interior of the sporogenous cavity4 ,this basal tissue 7the subarchesporial pad of ,bower#ajg7 has been observed in ,l4 clavatum to send up irregular processes of sterile cells among the developing spores1 suggesting a comparison with the trabeculae which form a characteristic feature of the sporangia of ,isoetes and with similar sterile strands noticed by ,bower#ajh in ,lepidostrobus 7cone of ,lepidodendron74 ,each sporophyll is supplied by a single vascular bundle which according to published statements never sends a branch to the sporangium base4 ,the fertile tips of the foliage shoots of ,l4 cernuum 7figs4 #abf1 ,a-,c7 afford good examples of specialised cones4 ,the surface of the cone is covered by the broadly triangular laminae of sporophylls 7fig4 #abf1 ,c7 which in their fimbriate margins resemble the ,palaeozoic cone-scales described by ,dr ,kidston#aji as ,lepidostrobus fimbriatus4 ,the distal portions of the sporophylls are prolonged downwards 7fig4 #abf1 ,a7 to afford protection to the lower sporangia1 their efficiency being increased by the lignified and thicker walls 7,a1 a7 of the cells in the lower portion of the laminar expansion4 ,the cells of the sporangial wall are provided with strengthening bands which in surface-view 7fig4 #abf1 ,b7 present the appearance of prominent pegs4 ,since the appearance of ,miss ,sykes's paper on the sporangium-bearing organs of the ,lycopodiaceae1 ,dr ,lang#aaj has published a more complete account of the structure of the strobilus of ,lycopodium cernuum in which he records certain features of special interest4 ,the importance of these morphological characters is increased by their agreement1 as shown by ,lang1 with those of the ,palaeozoic cone ,spencerites#aaa4 ,the sporophylls of a cone 7#ab mm4 long by #c mm4 in diameter7 of ,lycopodium cernuum show an abrupt transition from the foliage leaves1 but like these they occur in alternate whorls of five4 ,a large sporangium is attached to the upper face of each sporophyll close to the base of the obliquely vertical distal lamina 7fig4 #abg72 each sporophyll1 which is supplied with a single vascular bundle1 has a large mucilage-cavity 7m7 in its lower region4 8,the mucilaginous change0 in the sub-sporangial portion of a sporophyll 8extends to the surface involving the epidermis1 so that this portion of the sporophyll-base may be described as consisting of a mass of mucilage bounded below by a structureless membrane#aab40 ,dehiscence of the sporangia occurs at the middle of the distal face 7fig4 #abg1 x74 ,as seen in the radial section 7fig4 #abg1 ma7 the outer margin of the base of the sporophyll bears a short outgrowth4 ,the leaf-bases of each whorl hang down between the sporangia of the alternating whorl below1 and the base of each sporophyll is coherent with the margins of the two sporophylls of the next lower whorl between which it lies1 the sporangia being thus closely packed and lying in a pocket 8open only on the outer surface of the cone40 ,fig4 #abh represents a transverse section through a cone in the plane ,,aa of fig4 #abg2 this traverses the sporangia and their subtending bracts 7b7 of one whorl and the dependent bases of the sporophylls of the next higher whorl in the region of the mucilage-sacs 7m71 which are bounded at the periphery by the outer tissue of the sporophylls 7a74 ,a transverse section in the plane ,,bb of fig4 #abg is shown in fig4 #abi3 the pedicels and a part of each vascular strand are seen at b radiating from the axis of the cone2 one sporophyll 7sp1 a7 is cut through in the region of the pad of tracheal tissue that characterises the short sporangial stalks4 ,the upper portions of the sporangia of the next lower whorl1 which project upwards against the mucilaginous bases of the sporophylls above 7cf4 fig4 #abg1 ,,bb7 are shown at c and external to them1 at a1 the section has cut through the outer persistent portions of these sporophyll bases4 ,illustration3 ,,fig4 #abg4 ,radial longitudinal section of the cone of ,lycopodium cernuum4 7,after ,lang47 ,illustration3 ,,fig4 #abh4 ,transverse section of the cone of ,lycopodium cernuum1 in its plane ,,aa of fig4 #abg4 7,after ,lang47 ,illustration3 ,,fig4 #abi4 ,transverse section of the cone of ,lycopodium cernuum in the plane ,,bb of fig4 #abg4 7,after ,lang47 ,as ,lang points out1 this highly complex structure is an expression of the complete protection afforded to the sporangia of a plant met with in exposed situations in the tropics2 it is also of importance from a morphological standpoint as exhibiting an agreement with the extinct type of ,lycopod cone represented by ,spencerites4 ,selaginellaceae4 ,selaginella differs from ,lycopodium in the production of two kinds of spores1 megaspores and microspores1 and1 in the great majority of species1 in the dimorphic character of the foliage leaves1 which are usually arranged in four rows1 the laminae of the upper rows being very much smaller than those of the lower 7fig4 #acj1 #a-c74 ,the smaller leaves are shown more clearly in fig4 #acj1 #a;a4 ,it is obvious from an examination of a ,selaginella shoot1 such as is shown in fig4 #acj1 that in fossil specimens it would often be almost impossible to recognise the existence of two kinds of leaves4 ,some species1 e4g4 ,selaginella spinosa#aac1 the sole ,british representative of the genus1 are homophyllous and agree in this respect with most species of ,lycopodium4 ,another feature characteristic of ,selaginella1 as contrasted with ,lycopodium1 is the presence of a ligule in both foliage leaves and sporophylls4 ,this is a colourless thin lamina attached by a comparatively stout foot to the base of a pit on the upper surface and close to the lower edge of the leaf 7fig4 #acj1 #d1 l2 fig4 #aca1 ,e1 ,f1 l74 ,illustration3 ,,fig4 #acj4 ,selaginella grandis4 7#a-c1 nat4 size47 ,in an erect species1 such as ,s4 grandis ,moore#aad 7fig4 #acj and fig4 #aca1 ,g7 from ,borneo1 the main shoots1 which may attain a height of #b-c feet1 bear small and inconspicuous leaves of one kind1 but the lateral and repeatedly forked shoots are heterophyllous4 ,the passage from the homophyllous to the heterophyllous arrangement is shown in the transition from the erect to the dorsiventral habit of the lateral shoots 7fig4 #acj1 #b74 ,the monopodially or dichotomously branched shoots produce long naked axes at the forks2 these grow downwards to the ground where they develop numerous dichotomously forked branches4 ,for certain reasons these naked aerial axes were named rhizophores and have always been styled shoots1 the term root being restricted to repeatedly forked branches which the rhizophores produce in the soil4 ,it has1 however1 been shown by ,professor ,harvey-,gibson#aae that there is no sufficient reason for drawing any morphological distinction between rhizophores and roots1 the term root being applicable to both4 ,our knowledge of the anatomy of ,selaginella1 thanks chiefly to the researches of ,harvey-,gibson#aaf1 is much more complete than in the case of ,lycopodium4 ,the stems1 which may be either trailing or erect1 are usually dorsiventral1 and it is noteworthy that different shoots of the same plant or even the same axis in different regions may exhibit considerable variation in the structure and arrangement of the vascular tissue4 ,in the well-known species1 ,selaginella ,martensii1 the stem1 which is partly trailing1 partly ascending1 possesses a single ribbon-shaped stele composed of scalariform tracheids with two marginal protoxylems formed by the fusion of the leaf-traces of the dorsal and ventral leaves respectively4 ,as in ,lycopodium the metaxylem tracheae are as a rule scalariform1 but reticulate xylem elements are by no means unknown4 ,the tracheal band1 surrounded by parenchymatous elements1 is enclosed by phloem with external protophloem elements4 ,the characteristic features of the stele are shown in the diagrammatic drawing of a section of another species--,s4 ,willdenowii--represented in fig4 #aca1 ,a4 ,illustration3 ,,fig4 #aca4 ,a4 ,selaginella ,willdenowii4 ,transverse section of stem3 a1 outer cortex2 p1 phloem2 t1 trabeculae4 ,b4 ,s4 spinosa1 stem3 px1 protoxylem4 ,c4 ,s4 laevigata var4 ,lyallii1 section of stele3 t1 ridge of xylem cylinder2 e1 endodermis4 ,d4 ,s4 rupestris1 seedlings with cotyledons 7c7 protruding beyond the sporophylls 7b74 ,e4 ,transverse section of ,selaginella leaf-base3 l1 ligule2 lt1 leaf-trace4 ,f4 ,portion of ,g4 enlarged4 ,g4 ,s4 grandis4 ,longitudinal section of strobilus3 bb1 sporophyll-trace2 l1 ligule4 7,a1 ,b1 ,c1 ,e1 ,f1 after ,harvey-,gibson2 ,d1 after ,miss ,lyon47 ,a pericycle composed of one or two layers of chlorophyll-containing cells encircles the whole stele which is suspended in a lacuna by trabeculae 7fig4 #aca1 ,a1 ,b1 t7 connecting the pericycle with the inner edge of the broad cortex4 ,the trabeculae consist in part of endodermal cells characterised by cuticular bands4 ,the cortex is usually differentiated into three fairly distinct regions4 ,mechanical tissue of thick-walled fibres constitutes the outer region 7a72 the middle cortex consists of thinner-walled parenchyma1 the elements of which become smaller and rather more compactly arranged in the inner zone4 ,the middle cortex is frequently characterised by the presence of spaces and by the hyphal or trabecular structure of the tissue1 a feature which1 as ,bower#aag pointed out1 is common to many recent and fossil members of the ,lycopodiales4 ,in some cases1 e4g4 ,s4 erythropus1 from tropical ,america1 the cortex of the creeping stem consists entirely of thick-walled cells4 ,selaginella grandis 7fig4 #acj7 has 8a short decumbent stem rooted at close intervals#aah10 from which thick erect aerial shoots rise to a height of one foot or more4 ,in the apical region these erect axes give off repeatedly forked foliage shoots on which the spiral phyllotaxis of the homophyllous axis is gradually replaced by four rows of two kinds of leaves 7fig4 #acj1 #b74 ,the anatomy of this species agrees with that of ,s4 ,martensii4 ,the trailing or semi-erect and homophyllous shoots of ,selaginella spinosa#aai present a distinct type of vascular anatomy4 ,the upper part of the ascending stem has an axial strand of xylem with seven peripheral groups of spiral protoxylem tracheae 7fig4 #aca1 ,b72 in the trailing portion of the shoot the protoxylem elements occur as one central group in the solid rod of metaxylem through which the leaf-traces pass on their way to the axial protoxylem4 ,this type is important as affording an exception1 in the endarch structure of the xylem1 to the usual exarch plan of the stelar tissues4 ,this species is the only one in which any indication of the production of secondary xylem elements has so far been recorded4 ,bruchmann#abj has shown that1 in the small tuberous swelling which occurs at the base of the young shoot 7hypocotyl71 a meristematic zone is formed round the axial vascular strand and by its activity a few secondary tracheids are added to the primary xylem4 ,with this exception ,selaginella appears to have lost the power of secondary thickening1 the possession of which constitutes so striking a feature of the ,palaeozoic ,lycopods4 ,another type is represented by ,s4 inaequalifolia1 an ,indian species1 the shoots of which may have either a single stele or as many as five1 each in its separate lacuna4 ,the homophyllous ,s4 laevigata var4 ,lyallii ,spr41 a ,madagascan species1 affords a further illustration of the variation in plan of the vascular tissues within the genus4 ,there is a considerable difference in structure between the erect and creeping shoots2 in the former there may be as many as #ab-ac steles1 which gradually coalesce before the vertical axis joins the creeping rhizome to form one central and four peripheral steles4 ,in the rhizome there is usually a distinct axial stele without protoxylem1 surrounded by an ill-defined lacuna and enclosed by a cylindrical stele 7solenostele7#aba usually two tracheae in width with four protoxylem strands on its outer edge4 ,the continuity of the tubular stele is broken and1 in transverse section1 it assumes the form of a horse-shoe close to the base of an erect shoot to which a crescentic vascular strand is given off4 ,harvey-,gibson#abb has figured a section of the rhizome of this type in which the axial vascular strand is represented by a slight ridge of tracheae 7fig4 #aca1 ,c1 t7 projecting towards the centre of the axis of the tubular stele4 ,the cylindrical stele consists of xylem with external and internal phloem 7p73 cuticularised endodermal cells occur at e and e4 ,reference has already been made to the descending naked branches given off from the points of ramification of the foliage shoots of ,selaginella4 ,it has been shown by ,harvey-,gibson#abc that these branches1 originally designated rhizophores by ,ngeli and ,leitgeb1 as well as the dichotomously branched roots which they produce below the level of the ground1 possess a single vascular strand of monarch type4 ,it is interesting to find that in some species the aerial portion of the rhizophore has a xylem strand with a central protoxylem1 an instance of endarch structure like that in certain portions of the shoot-system of ,s4 spinosa4 ,the root-anatomy of ,selaginella and the dichotomous habit of branching afford points of agreement with the subterranean organs of ,lepidodendron and ,sigillaria4 ,leaves4 ,the leaves of ,selaginella#abd usually consist of a reticulum of loosely arranged cells1 but in some cases part of the mesophyll assumes the palisade form4 ,the single vascular bundle consists of a few small annular or spiral tracheae and at the apex of the lamina the protoxylem elements are accompanied by several short reticulated pitted elements4 ,both foliage leaves and sporophylls are characterised by the possession of a ligule1 a structure which may present the appearance of a somewhat rectangular plate 7fig4 #acj1 #d1 l1 and fig4 #aca1 ,e-,g1 l7 or assume a fan-shaped form with a lobed or papillate margin4 ,the base1 composed of large cells1 is sunk in the tissue of the leaf close to its insertion on the stem 7fig4 #aca1 ,e1 l7 and enclosed by a well-marked parenchymatous sheath4 ,the sheath is separated from the vascular bundle of the leaf by one or more layers of cells1 and in some species these become transformed into short tracheids4 ,the ligule is regarded by ,harvey-,gibson#abe as a specialised ramentum which serves the temporary function of keeping moist the growing-point and young leaves4 ,cones4 ,the terminal portions of the branches of ,selaginella usually bear smaller leaves of uniform size which function as sporophylls1 but in this genus the fertile shoots do not generally form such distinct cones as in many species of ,lycopodium4 ,in ,s4 grandis 7figs4 #acj1 #c2 #aca1 ,g7 the long and narrow strobili consist of a slender axis bearing imbricate sporophylls in four rows3 each sporophyll subtends a sporangium situated between the ligule and the axis of the shoot4 ,the sporangium may be developed from the axis of the cone or1 as in ,lycopodium1 from the cells of the sporophyll#abf4 ,in some species the lower sporophylls bear only megasporangia1 each normally containing four megaspores1 the microsporangia being confined to the upper part of the cone4 ,this distribution of the two kinds of sporangia is1 however1 by no means constant#abg3 in some cases1 e4g4 ,s4 rupestris1 cones may bear megasporangia only1 and in the cone of ,s4 grandis1 of which a small piece is represented in fig4 #aca1 ,g1 all the sporangia were found to contain microspores4 ,the occurrence of two kinds of spores in ,selaginella constitutes a feature of special importance from the point of view of the relationship between the ,phanerogams1 in which heterospory is a constant character1 and the heterosporous ,pteridophytes4 ,one of the most striking distinctions between the ,phanerogams and the rest of the vegetable kingdom lies in the production of seeds4 ,recent work has1 however1 shown that seed-production can no longer be regarded as a distinguishing feature of the ,gymnosperms and ,angiosperms4 ,palaeozoic plants which combined filicinean and cycadean features resembled the existing ,phanerogams in the possession of highly specialised seeds4 ,this discovery adds point to the comparison of the true seed with structures concerned with reproduction in seedless plants1 which in the course of evolution gave rise to the more efficient arrangement for the nursing1 protection1 and ultimate dispersal of the embryo4 ,in the megaspore of ,selaginella we have1 as ,hofmeister was the first to recognise in #ahea1 a structure homologous with the embryo-sac of the ,phanerogam4 ,the embryo-sac consists of a large cell produced in a mass of parenchymatous tissue known as the nucellus which is almost completely enclosed by one or more integuments4 ,fertilisation of the egg-cell within the embryo-sac takes place as a rule while the female reproductive organ is still attached to the parent-plant and separation does not occur until the ovule has become the seed4 ,in a few cases1 notably in certain plants characteristic of ,mangrove swamps1 continuity between the seed and its parent is retained until after germination4 ,the megasporangium of ,selaginella dehisces#abh along a line marked out by the occurrence of smaller cells over the crest of the wall4 ,it has been customary to describe the megaspores as being fertilised after ejection from the sporangia4 ,this earlier separation from the parent and the absence of any protective covering external to the spore-wall constitute two distinguishing features between seeds and megaspores4 ,in ,selaginella apus1 a ,californian species1 ,miss ,lyon has shown that fertilisation of the egg-cell usually takes place while the megaspore is still in the strobilus4 ,on examining withered decayed strobili of this species which had been partially covered with the soil for some months after fertilisation of the megaspores1 several young plants were found with cotyledons and roots projecting through the crevices of the megasporangia#abi4 ,from this1 adds ,miss ,lyon1 8it seems safe to assume that an embryo may have two periods of growth separated by one of quiescence quite comparable to those of seed plants with marked xerophilous features40 ,in another ,western ,american species ,s4 rupestris described by the same writer the cotyledons of young plants were found protruding from the imbricate sporophylls of a withered cone 7fig4 #aca1 ,d74 ,this species is interesting also from the occasional occurrence of one instead of four megasporangia in a sporangium2 a condition which affords another connecting link between the heterosporous ,pteridophytes1 on the one hand1 and the seed-bearing ,phanerogams in which the occurrence of a single embryo-sac 7megaspore7 in each ovule is the rule4 ,the cones of ,selaginella rupestris retain connexion with the plant through the winter and fertilisation occurs in the following spring4 ,after the embryo has been formed the megasporangium 8becomes sunken in a shallow pit formed by the cushion-like outgrowth of the sporophyll around the pedicel40 ,it is suggested that this outgrowth may be comparable with the integument which grows up from the sporophyll in the fossil genus ,lepidocarpon#acj and almost completely encloses the sporangium4 ,in the drawings given by ,miss ,lyon no features are recognisable which afford a parallel to the integument of ,lepidocarpon4 ,i have1 however1 endeavoured to show1 by a brief reference to this author's interesting account of the two ,californian species1 that the physiological and morphological resemblances between the megasporangia of ,selaginella and the integumented ovules of the seed-bearing plants are sufficiently close to enable us to recognise possible lines of advance towards the development of the true seed4 ,professor ,campbell#aca records an additional example of a ,selaginella--probably ,s4 ,bigelovii--from the dry region of ,southern ,california in which the spores become completely dried up after the embryo has attained some size1 remaining in that state until the more favourable conditions succeeding the dry season induce renewed activity4 ,isoetaceae4 ,the genus ,isoetes is peculiar among ,pteridophytes both in habit and in anatomical features4 ,in its short and relatively thick tuberous stem1 terminating in a crowded rosette of subulate leaves like those of ,juncus and bearing numerous adventitious roots1 ,isoetes presents an appearance similar to that of many monocotyledonous plants4 ,the habit of the genus is well represented by such species as ,isoetes lacustris and ,i4 echinospora#acb 7fig4 #acb7 both of which grow in freshwater lakes in ,britain and in other north ,european countries4 ,the latter species bears leaves reaching a length of #ah cm4 ,the resemblance in habit between this isolated member of the ,pteridophytes and certain ,flowering plants1 although in itself of no morphological significance1 is consistent with the view expressed by ,campbell that ,isoetes may be directly related to the ,monocotyledons#acc4 ,illustration3 ,,fig4 #acb4 ,isoetes echinospora 7,after ,motelay and ,vendrys74 ,a4 ,stem of ,i4 lacustris4 ,b4 ,base of sporophyll3 l1 ligule2 spg1 sporangium partially covered by velum4 ,there is as a rule little or no difference between the foliage leaves and sporophylls2 in ,i4 lacustris the latter are rather larger and in the terrestrial species ,i4 hystrix#acd the sterile leaves are represented by the expanded basal portions only1 which persist like the leaf-bases of ,lepidodendron as dark brown scales to form a protective investment to the older part of the stem4 ,the innermost leaves are usually sterile2 next to these are sporophylls bearing megasporangia1 and on the outside are the older sporophylls with microsporangia4 ,the long and slender portion of the leaf becomes suddenly expanded close to its attachment to the stem into a broad base of crescentic section which bears a fairly conspicuous ligule 7figs4 #acb1 ,b1 l1 #acc1 ,e1 l7 inserted by a foot or glossopodium in a pit near the upper part of the concave inner face4 ,the ligule is usually larger than that of ,selaginella1 though of the same type4 ,the free awl-like lamina contains four large canals bridged across at intervals by transverse diaphragms1 and in the axial region a single vascular bundle of collateral structure4 ,other vascular elements1 in the form of numerous short tracheids occur below the base of the transversely elongated ligule4 ,stomata are found on the leaves of ,i4 hystrix1 ,i4 ,boryana#ace1 and in other species which are not permanently submerged4 ,both microsporangia and megasporangia are characterised by their large size and by the presence of trabeculae or strands of sterile tissue 7fig4 #acc1 ,e1 ,h1 t7 completely bridging across the sporangial cavity or extending as irregular ingrowths among the spore-producing tissue4 ,similar sterile bands1 though less abundant and smaller1 are occasionally met with in the still larger sporangia of ,lepidostrobus2 these may be regarded as a further development of the prominent pad of cells which projects into the sporangial cavity in recent species of ,lycopodium 7fig4 #abf1 ,d1 p74 ,the sporangia are attached by a very short stalk to the base of a large depression in the leaf-base below the ligule1 from the pit of which they are separated by a ridge of tissue known as the saddle1 and from this ridge a veil of tissue 7the velum7 extends as a roof over the sporangial chamber 7fig4 #acc1 ,e1 v74 ,in most species there is a large gap between the lower edge of the velum and that of the sporangial pit1 but in ,i4 hystrix this protective membrane is separated from the base of the leaf by a narrow opening1 the resemblance of which to the micropyle of an ovule suggested to one of the older botanists the employment of the same term#acf4 ,mr ,t4 ,g4 ,hill#acg has called attention to the presence of mucilage canals in the base of the sporophylls of ,i4 hystrix1 which he compares with the strands of tissue known as the parichnos accompanying the leaf-traces of ,lepidodendron and ,sigillaria in the outer cortex of the stem4 ,the transverse section shown in fig4 #acc1 ,h and ,i1 shows two of these mucilage canals in an early stage of development2 a strand of parenchymatous elements distinguished by their partially disorganised condition and more deeply stained membranes 7fig4 #acc1 ,i7 runs through the spandrels of the sporophyll tissue close to the upper surface4 ,there is a close resemblance between the structure of these partially formed mucilage-canals and the tissue which has been called the secretory zone in ,lepidodendron stems4 ,fig4 #acc1 ,h1 also shows a large microsporangium with prominent trabeculae 7t7 lying below the velum4 ,a longitudinal section 7fig4 #acc1 ,e7 through a sporophyll-base presents an appearance comparable with that of an ,araucarian cone-scale with its integumented ovule and micropyle4 ,the megaspores are characterised by ridges1 spines1 and other surface-ornamentation#ach4 ,though usually unbranched1 the perennial stem of ,isoetes 7fig4 #acb7 has in rare cases been found to exhibit dichotomous branching1 a feature1 as ,solms-,laubach#aci points out1 consistent with a ,lycopodiaceous affinity4 ,the apex is situated at the base of a funnel-shaped depression4 ,the stem is always grooved2 in some species two and in others three deep furrows extend from the base up the sides of the short and thick axis towards the leaves3 from the sides of these furrows numerous slender roots are given off in acropetal succession4 ,a stele of peculiar structure occupies the centre of the stem2 cylindrical in the upper part 7fig4 #acc1 ,a71 it assumes a narrow elliptical or1 in species in which there are three furrows1 a triangular form in the lower portion of the tuberous stem4 ,sidenote3 ,,isoetes ,the stem of ,i4 lacustris represented in fig4 #acb1 ,a1 from which the laminae of the leaves have been removed from the summit affords an example of a species with two furrows4 ,the drawing shows the widely gaping sides of the broad furrow with circular root-scars and a few simple and dichotomously branched roots4 ,a short thick column of parenchymatous tissue projects from a slightly eccentric position on the base of the stem4 ,illustration3 ,,fig4 #acc4 ,isoetes lacustris4 ,a4 ,transverse section of stem3 cr1 cortex2 x1 x xylem2 c1 cambium2 a1 thin-walled tissue2 lt1 leaf-traces2 b1 dead tissue4 ,b1 ,c1 ,d4 ,portions of ,a enlarged4 ,e4 ,longitudinal radial section of sporophyll-base3 v1 velum2 l1 ligule2 bb2 vascular bundle2 m1 megaspores2 t1 sterile tissue4 ,f4 ,longitudinal section through the base of a root4 ,g4 ,transverse section of root4 ,h4 ,transverse section of sporophyll1 showing sporangium with trabeculae1 t2 leaf-trace1 7lt71 and two groups of secretory cells4 ,i4 ,a group of secretory cells enlarged4 ,the primary vascular cylinder#adj consists of numerous spiral1 annular or reticulate tracheids 7fig4 #acc1 ,a1 x7 which are either isodiametric or longer in a horizontal than in a vertical direction1 associated with parenchyma4 ,lower in the stem crushed and disorganised xylem elements are scattered through a still living trabecular network of parenchymatous tissue4 ,from the axial cylinder numerous leaf-traces 7fig4 #acc1 ,a1 lt7 radiate outwards1 at first in a horizontal direction and then gradually ascending towards the leaves4 ,the vascular cylinder is of the type known as cauline2 that is1 some of the xylem is distinct in origin from that which consists solely of the lower ends of leaf-traces4 ,as in ,lycopodium the development of the metaxylem is centripetal4 ,von ,mohl#ada1 and a few years later ,hofmeister#adb1 were the first botanists to give a satisfactory account of the anatomy of ,isoetes but it is only recently#adc that fresh light has been thrown upon the structural features of the genus the interest of which is enhanced by the many points of resemblance between the recent type and the ,palaeozoic ,lepidodendreae4 ,a striking anatomical feature is the power of the stem to produce secondary vascular and non-vascular tissue2 the genus is also characterised by the early appearance of secondary meristematic activity which renders it practically impossible to draw any distinct line between primary and secondary growth4 ,a cylinder of thin-walled tissue 7fig4 #acc1 ,a1 a7 surrounds the primary central cylinder and in this a cambial zone1 c1 is recognised even close to the stem-apex2 this zone of dividing cells is separated from the xylem by a few layers of rectangular cells to which the term prismatic zone has been applied4 ,the early appearance of the cambial activity on the edge of the vascular cylinder is shown in fig4 #acc1 ,c1 which represents part of a transverse section of a young stem4 ,a leaf-trace1 lt1 is in connexion with the primary xylem1 x1 which consists of short tracheids1 often represented only by their spiral or reticulately thickened bands of lignified wall1 and scattered parenchyma4 ,some of the radially elongated cells on the sides of the leaf-trace are seen to be in continuity on the outer edge of the stele1 at st1 with flattened elements1 some of which are sieve-tubes4 ,the position of a second leaf-trace is shown at lt4 ,external to the sieve-tubes the tissue consists of radially arranged series of rectangular cells1 some of which have already assumed the function of a cambium 7c74 ,the tissue produced by the cambium on its inner edge consists of a varying amount of secondary xylem composed of very short spiral tracheids2 a few of these may be lignified 7fig4 #acc1 ,a1 x7 while others remain thin4 ,phloem elements1 recognisable by the presence of a thickened reticulum enclosing small sieve-areas 7fig #acc1 ,b1 s7 are fairly abundant1 and for the rest this intracambial region is composed of thin-walled parenchyma4 ,in longitudinal section these tissues present an appearance almost identical with that observed in a transverse section4 ,fig4 #acc1 ,b represents a longitudinal section1 through the intracambial zone and the edge of the stele1 of a younger stem than that shown in fig4 #acc1 ,a4 ,most of the radially disposed cells internal to the meristematic region are parenchymatous without any distinctive features2 a few scattered sieve-tubes 7s7 are recognised by their elliptical sieve-areas and an occasional tracheid can be detected4 ,the cambium cuts off externally a succession of segments which constitute additional cortical tissue 7fig4 #acc1 ,a1 cr7 of homogeneous structure1 composed of parenchymatous cells containing starch and rich in intercellular spaces4 ,as the stem grows in thickness the secondary cortex reaches a considerable breadth and the superficial layers are from time to time exfoliated as strips of dead and crushed tissue 7fig4 #acc1 ,a1 b74 ,the diagrammatic sketch reproduced in fig4 #acc1 ,a1 serves to illustrate the arrangement and relative size of the tissue-regions in an ,isoetes stem4 ,in the centre occur numerous spirally or reticulate tracheae scattered in parenchymatous tissue which has been considerably stretched and torn in the peripheral region of the stele2 the radiating lines mark the position of the leaf-traces 7lt7 in the more horizontal part of their course4 ,the zone between the cambium 7c7 and the edge of the central cylinder consists of radially disposed secondary tissue of short1 and for the most part unlignified1 elements including sieve-tubes and parenchyma2 the secondary xylem elements consist largely of thin-walled rectangular cells with delicate spiral bands1 but discontinuous rows of lignified tracheae 7x7 occur in certain regions of the intracambial zone4 ,the rest of the stem consists of secondary cortex 7cr7 with patches of dead tissue 7b7 still adhering to the irregularly furrowed surface4 ,the structure of the cambium and its products is shown in the detailed drawing reproduced in fig4 #acc1 ,d4 ,many of the elements cut off on the inner side of the cambium exhibit the characters of tracheids3 most of these are unlignified1 but others have thicker and lignified walls 7tr74 ,i4 hystrix appears to be exceptional in retaining its leaf-bases1 which form a complete protective investment and prevent the exfoliation of dead cortex4 ,each leaf-trace consists of a few spiral tracheids accompanied by narrow phloem elements directly continuous with the secondary phloem of the intracambial zone4 ,dr ,scott and ,mr ,hill have pointed out that a normal cambium is occasionally present in the stem of ,i4 hystrix during the early stages of growth2 this gives rise to xylem internally4 ,the few phloem elements observed external to the cambium may be regarded as primary phloem1 a tissue not usually represented in an ,isoetes stem#add4 ,the occasional occurrence of this normal cambium1 may1 as ,scott and ,hill suggest1 be a survival from a former condition in which the secondary thickening followed a less peculiar course4 ,the lower leaf-traces become more or less obliterated as the result of the constant increase in thickness of the broad zone of secondary tissues through which they pass4 ,the adventitious roots are developed acropetally and arranged in parallel series on each side of the median line of the two or three furrows4 ,the three arms of the triangular stele of ,i4 hystrix and the two narrow ends of the long axis of the stele of ,i4 lacustris1 which in transverse section has the form of a flattened ellipse1 are built up of successive root-bases4 ,a root of ,isoetes 7fig4 #acc1 ,g7 possesses one vascular bundle1 x1 with a single strand of protoxylem1 px1 thus agreeing in its monarch structure with the root-bundle in ,selaginella and many species of ,lycopodium4 ,the cortical region of the root consists of a few layers of outer cortex succeeded by a large space1 formed by the breaking down of the inner cortical tissue1 into which the vascular bundle projects 7fig4 #acc1 ,f74 ,the peculiarity of the roots in having a hollow cortex and an eccentric vascular bundle was noticed by ,von ,mohl#ade4 ,in the monarch bundles1 as in the fistular cortex and dichotomous branching1 the roots of ,isoetes present a striking resemblance to the slender rootlets of the ,palaeozoic ,stigmaria 7see ,page #bdf74 ,the longitudinal section through the base of a root of ,isoetes lacustris shown in fig4 #acc1 ,f1 affords a further illustration of certain features common to the fossil and recent types4 ,,fossil ,,lycopodiales4 ,isoetaceae ,the geological history of this division of the ,pteridophyta is exceedingly meagre1 a fact all the more regrettable as it is by no means improbable that in the surviving genus ,isoetes we have an isolated type possibly of considerable antiquity and closely akin to such extinct genera as ,pleuromeia and ,sigillaria4 ,if ,saporta's ,lower ,cretaceous species ,isoetes ,choffati#adf1 or more appropriately ,isoetites ,choffati1 is correctly determined1 it is the oldest fossil member of the family and indeed the most satisfactory among the more than doubtful species described as extinct forms of ,isoetes4 ,isoetites4 ,the generic name ,isoetites was first used by ,mnster#adg in the description of a specimen1 from the ,jurassic lithographic slates of ,solenhofen in ,bavaria1 which he named ,isoetites crociformis4 ,the specific name was chosen to express a resemblance of the tuberous appearance of the lower part of the imperfectly preserved and indeterminable fossil to a ,crocus corm4 ,impressions of ,isoetes-like leaves from the ,inferior ,oolite of ,yorkshire figured by ,phillips#adh and afterwards by ,lindley#adi as ,solenites ,murrayana were compared by the latter author with ,isoetes and ,pilularia1 but these leaves are now generally assigned to ,heer's gymnospermous genus ,czekanowskia4 ,an examination of the structure of the epidermal cells of these ,jurassic impressions convinced me that they resemble recent coniferous needles more closely than the leaves of any ,pteridophyte4 ,the genus ,czekanowskia#aej is recognised by several authors as a probable member of the ,ginkgoales4 ,isoetites ,choffati4 ,saporta4 ,the late ,marquis of ,saporta founded this species on two sets of impressions from the ,urgonian 7,lower ,cretaceous7 of ,portugal which1 though not found in actual organic connexion1 may possibly be portions of the same plant4 ,small relatively broad tuberous bodies reaching a breadth of #a cm4 are compared with the short and broad stem of ,isoetes1 which they resemble in bearing numerous appendages radiating from the surface like the roots of the recent species2 on the exposed face of the stem occur scattered circular scars representing the position of roots which were detached before fossilisation4 ,other impressions are identified as the basal portions of sporophylls bearing sporangia3 these suggest the expanded base of the fertile leaves of ,isoetes with vertically elongated sporangia1 some of which have a smooth surface while in others traces of internal structure are exposed2 the interior consists of an irregular network with depressions containing carbonised remains of spores4 ,while recognising a general resemblance to the sporophylls of ,isoetes1 certain differences are obvious3 there is no ligule in the fossil leaves nor are there any distinct traces of vascular strands such as occur in the leaves of recent species4 ,the form of the sporangium1 more elongated than in the majority of recent forms1 is compared by ,saporta with that in a south ,european species ,isoetes setacea ,spr4 ,such evidence as we have lends support to the inclusion of these ,portuguese fossils in the genus ,isoetites1 but apart from the fact that we have no proof of any connexion between the stems and supposed sporophylls1 the resemblance of the latter to those of ,isoetes is1 perhaps1 hardly sufficient to satisfy all reasonable scepticism4 ,the generic name ,isoetopsis was used by ,saporta as more appropriate than ,isoetes for some ,eocene fossils from ,aix-en-,provence which are too doubtful to rank as trustworthy evidence of the existence of the recent genus4 ,the species1 ,isoetopsis subaphylla#aea is founded on impressions of small scales1 #d mm4 long1 bearing circular bodies which are compared with sporangia or spores4 ,other records of fossils referred to ,isoetes need not be described as they have no claim to be regarded as contributions towards the past history of the genus4 ,heer's ,miocene species ,isoetites ,scheuzeri and ,i4 ,braunii ,unger#aeb from ,switzerland are based on unsatisfactory material and are of no importance4 ,pleuromeia4 ,the generic name ,pleuromeia1 was suggested by ,corda#aec for a fossil from the ,bunter ,sandstone1 the original description of which was based by ,mnster#aed on a specimen discovered in a split stone from the tower of ,magdeburg ,cathedral4 ,the majority of the specimens have been obtained from the neighbourhood of ,bernburg1 but a few examples are recorded from ,commern and other ,german localities3 all are now included under the name ,pleuromeia ,sternbergi4 ,germar1 who published one of the earlier accounts of the species1 states that ,corda dissented from ,mnster's choice of the name ,sigillaria and proposed the new generic title ,pleuromeia4 ,one of the best descriptions of the genus we owe to ,solms-,laubach#aee whose paper contains references to earlier writers4 ,illustrations have been published by ,mnster1 ,germar#aef1 ,bischof#aeg1 ,solms-,laubach and ,potoni#aeh4 ,pleuromeia ,sternbergi4 7,mnster47 ,fig4 #acd4 #ahdb4 ,sigillaria ,sternbergii1 ,mnster4 #ahed4 ,sagenaria ,bischofii1 ,goeppert#aei4 #ahhe4 ,sigillaria oculina1 ,blanckenhorn4 #aijd4 ,pleuromeia oculina1 ,potoni4 ,pleuromeia ,sternbergi is represented by casts of vegetative and fertile axes1 but the preservation of the latter is not sufficiently good to enable us to draw any very definite conclusions as to the nature of the reproductive organs4 ,casts of the stems reach a length of about #a metre and a diameter of #e-f cm41 or in some cases #aj cm42 all of them are in a more or less decorticated state1 the degree of decortication being responsible for differences in the external features which led ,spieker#afj to adopt more than one specific name4 ,fig4 #acd1 ,a1 represents a sketch1 made some years ago1 of a specimen in the ,breslau ,museum which contains several examples of this species1 among others those described by ,germar in #aheb4 ,the cylindrical cast 7#ch cm4 long by #ab cm4 in circumference71 which has been slightly squeezed towards the upper end1 bears spirally arranged imperfectly preserved leaf-scars and the lower end shows the truncated base of one of the short ,stigmaria-like arms characteristic of the plant4 ,as shown clearly in a specimen originally figured by ,bischof and more recently by ,potoni#afa1 the stem-base is divided by a double dichotomy into four short and broad lobes with blunt apices and bent upwards like the arms of a grappling iron 7fig4 #acd1 ,d74 ,the surface of this basal region is characterised by numerous circular scars 7fig4 #acd1 ,d2 #d scars enlarged7 in the form of slightly projecting areas with a depression in the centre of each4 ,these are undoubtedly the scars of rootlets1 remains of which are occasionally seen radiating through the surrounding rock4 ,as seen in fig4 #acd1 ,d1 a1 the fractured surface of a basal area may reveal the existence of an axial vascular cylinder giving off slender branches to the rootlets4 ,illustration3 ,,fig4 #acd4 ,pleuromeia ,sternbergi4 ,a4 ,cast of stem in the ,breslau ,museum 7 nat4 size74 7,a4,c4,s47 ,b4 8,sigillaria oculina0 ,blanckenhorn4 7,after ,weiss74 ,c1 ,d4 ,leaf-scars and base of stem3 a1 vascular tissue4 7,after ,solms-,laubach47 ,the bulbous enlargement at the base of the ,brown seaweed ,laminaria bulbosa ,lam4#afb simulates the swollen base of ,pleuromeia2 but a confusion between these two plants is hardly likely to occur4 ,above the ,stigmaria-like base the gradually tapered axis1 in the less decorticated specimens1 bears spirally disposed transversely elongated areas consisting of two triangular scars between which is the point of exit of a leaf-trace4 ,the form of the leaf-scars is best seen on the face of a mould figured by ,solms-,laubach 7fig4 #acd1 ,c73 in this case the two triangular areas appear as slight projections separated by a narrow groove marking the position of the vascular bundle of the leaf4 ,the curved lines above and below the leaf-scar probably mark the boundary of the leaf-base4 ,the two triangular scars are compared by ,solms-,laubach and by ,potoni with the parichnos-scars of ,sigillaria and ,lepidodendron 7cf4 fig4 #adf1 ,c71 but the large size of the ,pleuromeia scars constitutes an obvious difference though possibly not a distinction of importance4 ,the occurrence of a vertical canal filled with carbonaceous material in some of the stems throws light on the internal structure3 the canal1 which is described by ,solms-,laubach as having a stellate outline in transverse section recalls the narrow central cylinder of a ,lepidodendron stem1 and this comparison is strengthened by the presence of obliquely ascending grooves which represent leaf-traces passing through the cortex4 ,in specimens which have lost more of the cortical tissues the surface is characterised by spirally disposed1 discontinuous vertical grooves representing portions of leaf-traces precisely as they appear in similar casts of ,lepidodendron4 ,there is no direct evidence of the existence of secondary wood in the stem1 but1 as ,potoni has pointed out1 the greater transverse elongation of the leaf-scars in the lower part of a cast 7fig4 #acd1 ,a7 points to the production of some secondary tissue either in the vascular cylinder or cortex1 or possibly in both regions4 ,in some specimens of ,pleuromeia the upper portion is clothed with crowded and imbricate sporophylls which reach a length of #be cm41 a maximum breadth of #bg cm41 and a thickness of #a mm4 ,each sporophyll has a thin wing-like border1 and on the lower face are several parallel lines4 ,solms-,laubach describes the sporangium or ovule as attached to the lower surface of the sporophyll and this opinion has been confirmed by ,fitting#afc who has also brought forward satisfactory evidence in favour of the sporangial nature of the reproductive organs4 ,fitting found numerous spores in the ,bunter ,sandstone near ,halle2 these are flattened circular bodies #je-jg mm4 in diameter with a granulated surface and the three converging lines characteristic of spores produced in tetrads4 ,the comparison made by this author between the sporophylls of ,pleuromeia1 which bore the sporangia on the lower surface instead of on the upper as in other lycopodiaceous plants1 and the pollen-sacs of ,conifers1 is worthy of note in reference to the possible relationship between ,conifers and ,lycopods4 ,a comparison of the ,isoetes stem represented in fig4 #acb1 ,a1 with the base of a ,pleuromeia shows a striking similarity1 but1 as ,fitting points out1 the ,stigmaria-like arms of the fossil contained a vascular cylinder whereas the blunt lobes of ,isoetes consist exclusively of cortical tissue1 the roots being given off from the grooves between the lobes of the tuberous stem4 ,the position of ,pleuromeia must for the present be left an open question2 it is1 however1 clear that the plant bears a close resemblance in the form of its base to the ,stigmarian branches of ,lepidodendron and ,sigillaria4 ,the vegetative shoot appears to be constructed on a plan similar to that of these two ,palaeozoic genera1 but the strobilus is of a different type4 ,it would seem probable that ,pleuromeia may be closely allied to ,isoetes and to the arborescent ,lycopods of ,palaeozoic floras4 ,it is not improbably a link in a chain of types which includes ,sigillaria on the one hand and ,isoetes on the other4 ,it is not improbable that a specimen from the ,lower ,bunter of ,commern which ,blanckenhorn made the type of a new species1 ,sigillaria oculina 7fig4 #acd1 ,b7 is specifically identical with ,pleuromeia ,sternbergi4 ,an examination of a cast of the type-specimen in the ,berlin ,bergakademie led me to regard the fossil with some hesitation as a true ,sigillaria1 but a more extended knowledge of ,pleuromeia lends support to the view adopted by ,potoni#afd that ,blanckenhorn's plant is not genetically distinct from ,pleuromeia ,sternbergi4 ,the resemblance between ,sigillaria oculina and some of the ,palaeozoic species of ,sigillaria emphasised by ,weiss#afe has given rise to the belief that the genus ,sigillaria persisted into the ,triassic era2 it is1 however1 highly probable that the ,bunter specimen has no claim to the generic name under which it has hither to been known4 ,the ,bunter ,sandstone in which ,pleuromeia is the sole representative of plant-life1 at least in certain localities1 is usually considered to be a desert formation4 ,we may not be far wrong in accepting ,fitting's suggestion that in this isolated species we have a relic of the sparse vegetation which was able to exist where the presence of lakes added a touch of life to the deadness of the ,triassic desert4 ,pleuromeia is recorded by ,fliche as a rare fossil in the ,middle ,trias of ,france in the neighbourhood of ,lunville#aff4 ,herbaceous fossil species of ,lycopodiales4 ,the history of our knowledge of fossil representatives of the ,lycopodiales1 as also of the ,equisetales1 affords a striking illustration of the danger of attempting to found a classification on such differences as are expressed by the terms herbaceous and arborescent in the sense in which they are usually employed4 ,as we have seen#afg1 the presence of secondary wood in stems of the ,palaeozoic plant now known as ,calamites led so competent a botanist as ,adolphe ,brongniart to recognise a distinct generic type ,calamodendron1 which he placed in the ,gymnosperms1 reserving the designation ,calamities for species in which no indication of secondary thickening had been found4 ,similarly1 the genus ,sigillaria was regarded as a ,gymnosperm because it was believed to be distinguished from ,lepidodendron by the power of forming secondary vascular tissues2 the latter genus1 originally thought to be always herbaceous1 was classed with the ,pteridophytes4 ,at the time when this unnatural separation was made between stems with secondary wood and those in which no secondary wood was known to exist1 botanists were not aware of the occurrence of any recent ,pteridophyte which shared with the higher plants the power of secondary growth in thickness provided by means of a meristematic zone4 ,it is true that the presence or absence of a cambium does not in practice always coincide with the division into herbaceous and arborescent plants3 no one would speak of a ,date-,palm as a herbaceous plant despite the absence of secondary wood4 ,the danger which should be borne in mind1 in adopting as a matter of convenience the term herbaceous as a sectional heading1 is that it should not be taken to imply a complete inability of the so-called herbaceous types to make secondary additions to their conducting tissues4 ,the specimens on which the species of ,lycopodites and ,selaginellites1 7genera which may be designated herbaceous17 are founded are preserved as impressions and not as petrifications2 we can1 therefore1 base definitions only on habit and on such features as are shown by fertile leaves and sporangia4 ,we are fully justified in concluding from evidence adduced by ,goldenberg more than fifty years ago and from similar evidence brought to light by more recent researches1 that there existed in the ,palaeozoic era lycopodiaceous species in close agreement in their herbaceous habit with the lycopods of present-day floras4 ,it has been suggested#afh that the direct ancestors of the genera ,lycopodium and ,selaginella are represented by the species of ,lycopodites and ,selaginellites rather than by ,lepidodendron and ,sigillaria1 the arborescent habit of which has been rendered familiar by the numerous attempts to furnish pictorial reproductions of a ,palaeozoic forest4 ,until we are able to subject the species classed as herbaceous to microscopical examination we cannot make any positive statement as to the correctness of this view1 but such facts as we possess lead us to regard the suggestion as resting on a sound basis4 ,palaeobotanical literature abounds in records of species of ,lycopodites1 ,lycopodium1 ,selaginella and ,selaginites1 which have been so named in the belief that their vegetative shoots bear a greater resemblance to those of recent lycopodiaceous plants than to the foliage shoots of ,lepidodendron4 ,many of these records are valueless3 ,lepidodendra1 twigs of ,bothrodendron#afi species of conifers1 fern rhizomes1 and ,aphlebiae#agj have masqueraded as herbaceous lycopods4 ,it is obvious that an attempt to identify fossils presenting a general agreement in habit and leaf-form with recent species of lycopods must be attended with considerable risk of error4 ,recent ,conifers include several species the smaller branches of which simulate the leafy shoots of certain species of ,lycopodium and ,selaginella1 and it is not surprising to find that this similarity has been responsible for many false determinations4 ,among ,mosses and the larger foliose ,liverworts there are species which in the condition of imperfectly preserved impressions1 might easily be mistaken for lycopodiaceous shoots3 an equally close resemblance is apparent in the case of some flowering plants1 such as ,new ,zealand species of ,veronica1 ,tafalla graveolens 7a ,composite71 ,lavoisiera lycopodiodes ,gard4#aga 7a species of ,melastomaceae71 all of which have the habit of ,cupressineae among the conifers as well as of certain lycopodiaceous plants4 ,it may be impossible to decide whether fossil impressions of branches1 which are presumably lycopodiaceous1 bear two kinds of leaves#agb like the great majority of recent species of ,selaginella4 ,selaginella grandis1 if seen from the under surface1 would appear to have two rows of leaves only and might be confused with a small twig of such a conifer as ,dacrydium ,kirkii1 a ,new ,zealand species4 ,the ,new ,zealand conifers ,dacrydium cupressinum ,soland4 and ,podocarpus dacrydioides ,rich4 closely simulate species of ,selaginellites and ,lycopodites3 in the ,british ,museum a specimen of the latter species bears a label describing it as ,lycopodium arboreum 7,sir ,joseph ,hooker and ,dr ,solander2 #agfi74 ,the twigs of the ,tasmanian conifer ,microcachyrs tetragona ,hook4 f4 are very similar in habit to shoots of the recent ,lycopodium tetragonum 7fig4 #aba1 ,c74 ,in the description of examples of ,lycopodites and ,selaginellites ,i have confined myself to such as appear to be above suspicion either because of the presence of spore-bearing organs or1 in a few cases1 because the specimens of sterile shoots are sufficiently large to show the form of branching in addition to the texture of the leaves4 ,the two generic names ,lycopodites and ,selaginellites are employed for fossil species which there are substantial grounds for regarding as representatives of ,lycopodium and ,selaginella4 ,the designation ,selaginellites is adopted only for species which afford evidence of heterospory2 the name ,lycopodites1 on the other hand1 is used in a comprehensive sense to include all forms--whether homophyllous or heterophyllous--which are not known to be heterosporous4 ,this restricted use of the generic name ,selaginellites is advocated by ,zeiller#agc1 who instituted the genus1 and by ,halle#agd in his recent paper on herbaceous lycopods4 ,lycopodites4 ,the generic term ,lycopodites was used by ,brongniart in #ahbbage in describing some ,tertiary examples of slender axes clothed with small scale-like leaves which he named ,lycopodites squamatus4 ,these are fragments of coniferous shoots4 ,in the ,prodrome d'une histoire des vgtaux fossiles#agf ,brongniart included several ,palaeozoic and ,jurassic species in ,lycopodites and instituted a new genus ,selaginites1 expressing a doubt as to the wisdom of attempting to draw a generic distinction between the two sets of species4 ,in a later work#agg he recognised only one undoubted species1 ,lycopodites falcatus4 ,the first satisfactory account of fossils referred to ,lycopodites is by ,goldenberg#agh who gave the following definition of the genus3--8,branches with leaves spirally disposed or in whorls4 ,sporangia in the axil of foliage leaves or borne in terminal strobili40 ,it was suggested by ,lesquereux#agi that ,goldenberg's definition1 which was intended to apply to herbaceous species1 should be extended so as to include forms with woody stems but which do not in all respects agree with ,lepidodendron4 ,kidston#ahj subsequently adopted ,lesquereux's modification of ,goldenberg's definition4 ,we cannot draw any well-defined line between impressions of herbaceous forms and those of small arborescent species4 ,we use the name ,lycopodites for such plants as appear to agree in habit with recent species of ,lycopodium and ,selaginella and which1 so far as we know1 were not heterosporous3 it is highly probable that some of the species so named had the power of producing secondary wood1 a power possessed by some recent ,pteridophytes which never attain the dimensions of arborescent plants4 ,it has been shown by ,halle#aha1 who has re-examined several of ,goldenberg's specimens which have been acquired by the ,stockholm ,palaeobotanical ,museum1 that some of his species of ,lycopodites are heterosporous and therefore referable to ,zeiller's genus ,selaginellites4 ,in #ahfi ,renault described two species of supposed ,palaeozoic ,lycopods as ,lycopodium punctatum and ,l4 ,renaultii#ahb1 the latter name having been suggested by ,brongniart to whom specimens were submitted4 ,these species were afterwards recognised by their author as wrongly named and were transferred to the genus ,heterangium#ahc1 a determination which is probably correct2 it is at least certain that the use of the name ,lycopodium cannot be upheld4 ,we have unfortunately to rely on specimens without petrified tissues for our information in regard to the history of ,lycopodites and ,selaginellites4 ,among the older fossils referred to ,lycopodites are specimens from ,lower ,carboniferous rocks at ,shap in ,westmoreland which ,kidston originally described as ,lycopodites ,vanuxemi#ahd1 identifying them with ,goeppert's ,sigillaria ,vanuxemi#ahe founded on ,german material4 ,in a later paper ,kidston transferred the ,british specimens of vegetative shoots to a new genus ,archaeosigillaria#ahf4 ,lycopodites ,stockii ,kidston#ahg4 ,the plant so named was discovered in ,lower ,carboniferous strata of ,eskdale1 ,dumfries1 ,scotland2 it is represented by imperfectly preserved shoots bearing a terminal strobilus and was originally described by ,kidston as apparently possessing two kinds of foliage leaves borne in whorls4 ,the larger leaves have an ovate cordate lamina with an acuminate apex1 while the smaller leaves1 which are less distinct1 are transversely elongated1 and simulate sporangia in appearance4 ,dr ,kidston's figure of this species has recently been reproduced by ,professor ,bower#ahh who speaks of the supposed smaller leaves as sporangia1 a view with which the author of the species agrees4 ,it would appear that this identification is1 however1 based solely on external resemblance and has not been confirmed by the discovery of any spores4 ,assuming the sporangial nature of these structures1 this ,palaeozoic type represents1 as ,bower points out1 a condition similar to that in some recent species of ,lycopodium in which sporangia are not confined to a terminal strobilus but occur also in association with ordinary foliage leaves4 ,the strobilus consists of crowded sporophylls which are too imperfect to afford any definite evidence as to their homosporous or heterosporous nature4 ,as ,solms-,laubach#ahi points out1 this type recalls ,lycopodium ,phlegmaria among recent species4 ,lycopodites ,reidii ,penhallow4 ,professor ,penhallow#aij instituted this name for a specimen measuring #h cm4 long by #f mm4 in breadth1 collected by ,mr ,reid from the ,old ,red ,sandstone of ,caithness1 consisting of an axis bearing narrow lanceolate leaves some of which bear sporangia at the base4 ,lycopodites ,gutbieri ,goeppert#aia4 #ahid1 ,lycopodites elongatus ,kidston#aib 7not ,goldenberg74 ,the species1 figured by ,geinitz as ,lycopodites ,gutbieri#aic1 from the ,coal-,measures of ,saxony is probably a true representative of the genus4 ,the ,saxon specimens are heterophyllous2 the larger lanceolate and slightly falcate leaves arranged in two rows1 are #d-e mm4 long while the smaller leaves are one half or one third this size2 some of the dichotomously branched shoots terminate in long and narrow strobili not unlike those of ,zeiller's species ,selaginellites ,suissei#aid4 ,kidston#aie has included under this specific name some fragments collected by ,hemingway from the ,upper ,coal-,measures of ,radstock1 ,somersetshire1 but as only one form of leaf is seen the reasons for adopting ,goeppert's designation are perhaps hardly adequate4 ,lycopodites ciliatus ,kidston#aif4 ,under this name ,kidston describes a small specimen1 obtained by ,hemingway from the ,middle ,coal-,measures of ,barnsley in ,yorkshire1 consisting of a slender forked axis bearing oval-acuminate leaves approximately #e mm4 long with a finely ciliate margin4 ,associated with the leaves were found spores which ,kidston regards as megaspores4 ,lycopodites macrophyllus ,goldenberg#aig4 ,this species1 originally described by ,goldenberg from the ,coal-,measures of ,saarbrcken has been re-examined by ,halle#aih who is unable to confirm ,goldenberg's statement as to heterophylly4 ,the shoots closely resemble ,selaginellites primaevus#aii 7,gold74 ,illustration3 ,,fig4 #ace4 ,selaginellites and ,lycopodites4 7,after ,halle47 ,a4 ,selaginellites primaevus 7,gold474 #aj4 ,b4 ,megaspore of ,selaginellites elongatus 7,gold474 #ej4 ,c4 ,lycopodites ,zeilleri ,halle4 7,nat4 size47 ,d4 ,selaginellites elongatus 7,gold474 #b4 ,lycopodites ,zeilleri ,halle#bjj4 ,fig4 #ace1 ,c4 ,halle has founded this species on specimens1 from the ,coal-,measures of ,zwickau in ,saxony1 characterised by dimorphic lanceolate leaves in four rows1 the larger being #d-f mm4 long3 the smaller leaves have a ciliate edge4 ,a comparison is made with the recent species ,selaginella arabica ,baker1 ,s4 revoluta ,bak41 and ,s4 armata ,bak4 in which the leaves are described as ciliate4 ,in the absence of sporangia and spores the species is placed in the genus ,lycopodites4 ,lycopodites lanceolatus 7,brodie74 ,fig4 #acf4 #ahde ,naiadita lanceolata1 ,brodie#bja4 ,naiadea acuminata1 ,buckman#bjb4 #ahej ,naiadea lanceolata1 ,buckman#bjc4 ,naiadea petiolata1 ,buckman#bjd4 #aijj ,naiadites acuminatus1 ,wickes#bje4 #aija ,naiadita lanceolata1 ,sollas#bjf 7figures showing habit of the plant74 #aijd ,lycopodites lanceolatus1 ,seward#bjg 7figure showing habit of the plant74 ,illustration3 ,,fig4 #acf4 ,lycopodites lanceolatus 7,brodie74 7,after ,miss ,sollas4 #dj47 a1 ,sporangium wall2 b1 leaf4 c1 remains of tubular elements in stem4 ,specimens referred to this species were originally recorded by ,brodie from ,rhaetic rocks in the ,severn valley1 the name ,naiadita being chosen as the result of ,lindley's comparison of the small and delicate leaves with those of recent species of the ,monocotyledonous family ,naiadaceae4 ,the species may be described as follows3 ,plant slender and moss-like in habit4 ,the axis1 which is delicate and thread-like1 bears numerous linear acuminate or narrow ovate leaves reaching a length of approximately #e mm4 ,under a low magnifying power the thin lamina of the leaves is seen to have a superficial layer of polygonal or rectangular cells arranged in parallel series 7fig4 #acf b74 ,there is no trace of midrib or stomata4 ,the sporangia are more or less spherical and short-stalked1 situated at the base of the foliage leaves and containing numerous tetrads of spores4 ,the spores have a diameter of #jjh mm4 ,buckman founded additional species on differences in the shape of the leaves but1 as ,miss ,sollas has pointed out1 such differences as he noticed may be detected on the same axis4 ,it was stated in an earlier chapter#bjh that ,starkie ,gardner1 on insufficient evidence1 proposed to place ,brodie's plant among the ,mosses4 ,the discovery by ,mr ,wickes of new material at ,pylle hill near ,bristol afforded an opportunity for a re-examination of the species3 this was successfully undertaken by ,miss ,sollas who was able to dissolve out spores from the matrix by dilute hydrochloric acid1 and to recognise the remains of internal structure in the slender axes by exposing successive surfaces with the aid of a hone4 ,it was found that sporangia occurred at the base of some of the leaves containing numerous tetrads of spores1 the individual spores having a diameter of #jjh mm41 apparently twice as large as those of any recent species of ,lycopodium4 ,fig4 #acf shows a sporangium1 a1 at the base of a leaf1 b4 ,indications of tubular elements were recognised in the stem and it is noteworthy that although the outlines of epidermal cells on the leaves are well preserved no stomata were found4 ,the leaves of the recent ,american species ,lycopodium alopecuroides ,linn4 var4 aquaticum ,spring#bji1 which lives under water1 possess stomata4 ,it is probable that in ,lycopodites lanceolatus the leaves had a very thin lamina and may have been similar in structure to those of recent ,mosses2 the plant possibly lived in very humid situations or grew submerged4 ,miss ,sollas's investigations afford a satisfactory demonstration of the lycopodiaceous nature of this small ,rhaetic species3 as ,i have elsewhere suggested#baj1 the generic name ,lycopodites should be substituted for that of ,naiadita4 ,examples of this species may be seen in the ,british ,museum4 ,the ,rhaetic species from ,scania1 ,lycopodites scanicus ,nath4#baa 7in litt471 recently re-described by ,halle and originally referred by ,nathorst to ,gleichenia affords another example of the occurrence of a small herbaceous lycopod of ,rhaetic age4 ,illustration3 ,,fig4 #acg4 ,lycopodites falcatus ,l4 and ,h4 ,from the ,inferior ,oolite of ,yorkshire4 7,nat4 size4 ,m4,s47 ,lycopodites falcatus ,lind4 and ,hutt4 ,fig4 #acg4 #ahca ,lycopodites falcatus1 ,lindley and ,hutton#bab4 #ahch ,muscites falcatus1 ,sternberg#bac4 #ahgj ,lycopodium falcatum1 ,schimper#bad4 ,in #ahbb ,young and ,bird#bae figured a specimen from the ,inferior ,oolite rocks of the ,yorkshire coast bearing 8small round crowded leaves10 which was afterwards described by ,lindley from additional material obtained from ,cloughton near ,scarborough as ,lycopodites falcatus4 ,the example represented in fig4 #acg shows the dichotomously branched shoots bearing two rows of broadly falcate leaves4 ,a careful examination of the type-specimen#baf revealed traces of what appeared to be smaller leaves1 but there is no satisfactory proof of heterophylly4 ,no sporangia or spores have been found4 ,this ,british species has been recorded from ,lower ,jurassic or ,rhaetic rocks of ,bornholm#bag and a similar though probably not identical type1 ,lycopodites ,victoriae#bah1 has been recognised in ,jurassic strata of ,australia 7,south ,gippsland1 ,victoria74 ,an ,indian plant described by ,oldham and ,morris#bai from the ,jurassic flora of the ,rajmahal hills as ,araucarites 787 gracilis and subsequently transferred by ,feistmantel to ,schimper's genus ,cheirolepis#bbj may be identical with the ,yorkshire species4 ,the ,jurassic fragments described by ,heer from ,siberia as ,lycopodites tenerrimus#bba may be lycopodiaceous1 but they are of no botanical interest4 ,other examples of ,mesozoic ,lycopods have been recorded1 but in the absence of well-preserved shoots and sporangia they are noteworthy only as pointing to a wide distribution of ,lycopodites in ,jurassic and ,cretaceous floras#bbb4 ,from ,tertiary strata species of supposed herbaceous lycopods have been figured by several authors1 one of the best of which is ,selaginella ,berthoudi ,lesq4#bbc from ,tertiary beds in ,colorado4 ,this species agrees very closely in the two forms of leaf with ,selaginella grandis1 but as the specimens are sterile we have not sufficient justification for the employment of the generic name ,selaginellites4 ,selaginellites4 ,this generic name has been instituted by ,zeiller#bbd for specimens from the coal basis of ,blanzy 7,france74 ,it is applied to heterosporous species with the habit of ,selaginella3 ,zeiller preferred the designation ,selaginellites to ,selaginella on the ground that the type species differs from recent forms in having more than four megaspores in each megasporangium4 ,it is1 however1 convenient to extend the term to all heterosporous fossil species irrespective of the spore-output4 ,selaginellites ,suissei ,zeiller4 ,this species was described in ,zeiller's preliminary note#bbe as ,lycopodites ,suissei1 but he afterwards transferred it to the genus ,selaginellites4 ,in habit the plant bears a close resemblance to ,lycopodites macrophyllus of ,goldenberg2 the shoots1 #a-c mm4 thick1 are branched in a more or less dichotomous fashion and bear tetrastichous leaves4 ,the larger leaves reach a length of #d-f mm4 and a breadth of #b-c mm42 the smaller leaves are described as almost invisible1 closely applied to the axis1 oval-lanceolate and #a-b mm4 long with a breadth of #je-jge mm4 ,long and narrow strobili 7#ae cm4 by #h-aj mm47 terminate the fertile branches2 these bear crowded sporophylls with a triangular lamina and finely denticulate margin4 ,oval sporangia were found on the lower sporophylls containing #af-bd spherical megaspores #jf-jfe mm4 in diameter4 ,the outer membrane of the spore is characterised by fine anastomosing ridges and thin plates radiating from the apex and forming an equatorial collarette4 ,the microspores have a diameter of #dj-fj and the same type of outer membrane as in the megaspores4 ,the megaspores of the recent species ,selaginella caulescens1 as figured by ,bennie and ,kidston#bbf1 resemble those of the ,palaeozoic type in the presence of an equatorial flange4 ,it is interesting to find that1 in spite of the occurrence of #af-bd megaspores in a single sporangium the size of the fossil spores exceeds that of the recent species4 ,selaginellites primaevus 7,gold474 ,fig4 #ace1 ,a1 fig4 #ach4 #ahee ,lycopodites primaevus1 ,goldenberg#bbg4 #ahgj ,lycopodium primaevum1 ,schimper#bbh4 #aijg ,selaginellites primaevus1 ,halle#bbi4 ,illustration3 ,,fig4 #ach4 ,selaginellites primaevus 7,gold474 7,after ,goldenberg47 ,in habit this species1 first recorded by ,goldenberg from the ,coal-,measures of ,saarbrcken1 is similar to ,s4 ,suissei ,zeill4 ,the drawing reproduced in fig4 #ach is a copy of that of the type-specimen3 another specimen1 named by ,goldenberg1 is figured by ,halle in his recently published paper4 ,the leaves appear to be distichous3 no smaller leaves have been detected1 though ,halle is inclined to regard the plant as heterophyllous4 ,the sporophylls1 borne in slender terminal strobili1 are smaller than the foliage leaves and spirally disposed 7fig4 #ach2 smaller specimen74 ,halle succeeded in demonstrating that some of the sporangia contained a single tetrad of spores1 each spore having a diameter of #jd-je mm4 ,no microspores were found1 but it is clear that the species was heterosporous and that it agrees with recent species in having only four spores in the megasporangium4 ,selaginellites elongatus 7,gold474 ,fig4 #ace1 ,b1 ,d4 #ahee ,lycopodites elongatus1 ,goldenberg#bcj4 #ahgj ,lycopodium elongatum1 ,schimper#bca4 ,the shoots of this species resemble the recent ,lycopodium complanatum2 they differ from those of ,selaginellites primaevus in their long and narrow branches which bear two forms of leaf4 ,the longer leaves1 arranged in opposite pairs1 are slightly falcate2 the smaller leaves are appressed to the axis and have a triangular cordate lamina4 ,another peculiarity of this species is the occurrence of sporangia in the axil of the foliage leaves1 a feature characteristic of the recent ,lycopodium ,selago4 ,in recent species of ,selaginella the sporophylls are always in strobili4 ,no microspores have been found nor the walls of megasporangia1 but tetrads of megaspores were isolated by ,halle3 the spores have three radiating ridges 7fig4 #ace1 ,b7 connected by an equatorial ridge4 ,halle estimates the number of spores 7#jde mm4 in diameter7 in a sporangium at #bj to #cj4 ,in size as in number the spores exceed those of recent species and agree more nearly with the megaspores of ,s4 ,suissei4 ,it would seem to be a general rule that the spores 7megaspores7 of the fossil herbaceous species exceeded considerably in dimensions those of recent forms and on the other hand were smaller than those of the ,palaeozoic arborescent species4 ,there can be little doubt that some of the ,mesozoic and ,tertiary species included under ,lycopodites agree more closely with the recent genus ,selaginella than with ,lycopodium1 but this does not constitute an argument of any importance against the restricted use of the designation ,selaginellites which we have adopted4 ,from a botanical point of view the various records of ,lycopodites and ,selaginellites have but a minor importance2 they are not sufficiently numerous to throw any light on questions of distribution in former periods1 nor is the preservation of the material such as to enable us to compare the fossil with recent types either as regards their anatomy or1 except in a few cases1 their sporangia and spores4 ,the ,palaeozoic species are interesting as revealing less reduction in the number of spores produced in the megasporangia4 ,among existing ,pteridophytes the genus ,isoetes agrees more closely than ,selaginella1 as regards the number of megaspores in each sporangium1 with such fossils as ,selaginellites ,suissei and ,s4 elongatus4 ,it would seem that in most ,palaeozoic species heterospory had not reached the same stage of development as in the recent genus ,selaginella in which the megaspores do not exceed four in each sporangium4 ,in ,selaginellites primaevus1 however1 the heterospory appears to be precisely of the same type as in existing species4 ,lycostrobus4 ,the generic name ,lycostrobus has recently been instituted by ,nathorst#bcb for certain specimens of a lycopodiaceous strobilus1 from the ,rhaetic strata of ,scania1 which he formerly referred to the genus ,androstrobus#bcc4 ,lycostrobus ,scotti ,nathorst4 ,fig4 #aci4 ,the fossil described under this name is of special interest as affording an example of a ,mesozoic lycopodiaceous cone comparable in habit and in size with some of the largest examples of ,palaeozoic ,lepidostrobi1 the cones of ,lepidodendron4 ,the ,swedish fossil from ,upper ,rhaetic strata of ,helsingborg 7,scania7 was originally designated ,androstrobus ,scotti1 the generic name being adopted in view of the close resemblance of the form of the strobilus to the male flower of a ,cycad4 ,a more complete examination has shown that the bodies1 which were thought to be pollen-sacs--though ,nathorst recognised certain differences between them and the pollen-sacs of lycopods--are the megaspores of a lycopod4 ,microspores have also been identified4 ,the axis of the cone has a breadth of #b cm4 with a peduncle which may be naked or provided with a few small scales2 the sporophyll region of the axis reached a length of at least #ab cm4 ,the spirally disposed sporophylls terminate in a rhombic distal end which may represent the original termination or they may have been prolonged upwards as free laminae4 ,each sporophyll bears on its upper face a single large sporangium containing either megaspores or microspores3 the megaspores1 #jee-jfj mm4 in diameter1 are finely granulate and bear small warty thorns or more slender pointed appendages4 ,the microspores1 after treatment with eau de ,javelle1 were found to measure #cf-dd while others which had been treated with ammonia reached #ed in diameter4 ,nathorst describes the microspores as occurring in spherical groups or balls1 which it is suggested may be compared with the groups of spores separated by strands of sterile tissue 7trabeculae7 in the large sporangia of ,isoetes 7cf4 fig4 #acc1 ,h74 ,if this comparison is sound it would point to a more complete septation of the sporangium in ,lycostrobus than in any recent species of ,isoetes4 ,the size of the strobilus would seem to indicate the persistence into the ,rhaetic era of an arborescent lycopodiaceous type2 but the appearance and manner of preservation of the axis is interpreted by ,nathorst as evidence of a herbaceous rather than a woody structure4 ,he is disposed to regard ,isoetes as the most nearly allied existing genus4 ,illustration3 ,,fig4 #aci4 ,lycostrobus ,scotti1 ,nath4 7,after ,nathorst2 nat4 size47 ,the comparison made by ,nathorst with ,isoetes is based on a resemblance between the spores of the two genera and on the evidence1 which is not decisive1 of the existence of sterile strands of tissue in the sporangia of ,lycostrobus4 ,this similarity is however hardly of sufficient importance to justify the inclusion of the ,rhaetic strobilus in the ,isoetaceae4 ,in size and in the arrangement and form of the sporophylls the cone presents a much closer resemblance to ,lepidodendron than to ,isoetes4 ,it is probably advisable to regard this ,rhaetic type simply as a lycopodiaceous genus which we are unable1 without additional information1 to assign to a particular position4 ,the opinion expressed by ,professor ,fliche#bcd that the plant described by ,schimper and ,mougeot as ,caulopteris tessellata1 a supposed tree-fern stem1 from ,triassic rocks of ,lorraine1 is more probably a large lycopodiaceous stem1 either a ,lepidodendron or a new genus1 is worthy of note in reference to ,nathorst's account of ,lycostrobus4 ,in habit the fossil strobilus may be compared with the ,triassic genus ,pleuromeia1 but the position of the sporangia on the sporophylls constitutes a well-marked difference4 ,the most important result of ,nathorst's skillful treatment of this interesting fossil by chemical microscopic methods is the demonstration of the existence of a large heterosporous type of lycopodiaceous cone in a ,rhaetic flora4 ,poecilitostachys4 ,under this generic name ,m4 ,fliche#bce has briefly described a fertile lycopodiaceous shoot from the ,triassic rocks of ,epinal in ,france3 the type species ,poecilitostachys ,hangi consists of a cylindrical axis1 #aj cm4 #e mm41 deprived of leaves and terminating in a rounded receptacle bearing a capitulum of bracts or fertile leaves4 ,detached megasporangia containing small globular bodies found in association with the capitulum are compared with the megasporangia of ,isoetes4 ,,chapter ,,xv4 ,arborescent ,lycopodiales4 ,among the best known plants in the ,palaeozoic floras are the genera ,lepidodendron and ,sigillaria1 types which are often spoken of as ,giant ,club-,mosses or as ancestors of existing species of ,lycopodium and ,selaginella4 ,of these genera1 but more particularly of ,lepidodendron1 we possess abundant records in a condition which have made it possible to obtain fairly complete information not only in regard to habit and external features but as to the anatomical characters of both vegetative and reproductive shoots4 ,the structure of ,lepidodendron differs too widely from that of recent ,club-,mosses 7species of ,lycopodium7 to justify the statement that this prominent member of the ,palaeozoic vegetation may be regarded as a direct ancestor of any living plant4 ,there is at least no doubt that ,lepidodendron and ,sigillaria must be included in the ,pteridophyta4 ,the description by ,dr ,scott#bcf of the genus ,lepidocarpon1 founded on petrified specimens of strobili1 demonstrated the existence of a type of lycopodiaceous plant in the ,carboniferous period distinguished from all living representatives of the group by the possession of integumented megaspores1 which may fairly be styled seeds4 ,lepidocarpon and another seed-bearing plant ,miadesmia are described under a separate heading as lycopodiaceous types characterised by an important morphological feature1 which among recent plants constitutes a differentiating character between the ,pteridophytes and the ,phanerogams4 ,lepidodendron4 i4 ,general4 ,the genus ,lepidodendron included species comparable in size with existing forest trees4 ,a tapered trunk rose vertically to a height of #ajj feet or upwards from a dichotomously branched subterranean axis of which the spreading branches1 clothed with numerous rootlets1 grew in a horizontal direction probably in a swampy soil or possibly under water4 ,a description by ,mr ,rodway#bcg of ,lycopods on the border of a savannah in ,guiana forming a miniature forest of ,pine-like ,lycopodiums might1 with the omission of the qualifying adjective1 be applied with equal force to a grove of ,lepidodendra4 ,the equal dichotomy of many of the branches gave to the tree a habit in striking contrast to that of our modern forest trees1 but1 on the other hand1 in close agreement with that of such recent species of ,lycopodium as ,l4 cernuum 7fig4 #abc71 ,l4 obscurum 7fig4 #abd7 and other types4 ,linear or oval cones terminated some of the more slender branches 7fig4 #ahh7 agreeing in size and form with the cones of the ,spruce ,fir and other conifers or with the male flowers of species of ,araucaria1 e4g4 ,a4 imbricata4 ,needle-like leaves1 varying considerably in length in different species1 covered the surface of young shoots in crowded spirals and their decurrent bases or leaf-cushions formed an encasing cylinder continuous with the outer cortex4 ,the fact that leaves are usually found attached only to branches of comparatively small diameter would seem to show that ,lepidodendron1 though an evergreen1 did not retain its foliage even for so long a period as do some recent conifers4 ,by the activity of a zone of growing tissue encircling the cylinder of wood the main trunk and branches grew in thickness year by year3 the general uniformity in size of the secondary conducting elements affords no indication of changing seasons4 ,as the branches grew stouter and shed their leaves the surface of the bark resembled in some degree that of a ,spruce ,fir and other species of ,picea1 in which the leaf-scars form the upper limit of prominent peg-like projections1 which1 at first contiguous and regular in contour1 afterwards become less regular and separated by grooves 7fig4 #adj7 and at a later stage lose their outline as the bark is stretched to the tearing point 7fig4 #adj1 ,c74 ,the leafless branches of ,lepidodendron were covered with spirally disposed oval cushions less peg-like and larger than the decurrent leaf-bases of ,picea1 which show in the upper third of their length a clean-cut triangular area and swell out below into two prominent cheeks separated by a median groove and tapering with decreasing thickness to a pointed base1 which in some forms 7e4g4 ,lepidodendron ,veltheimianum1 fig4 #ahe1 ,c1 ,d71 is prolonged as a curved ridge to the summit of a lower leaf-cushion4 ,illustration3 ,,fig4 #adj4 ,picea excelsa4 ,shoots of different ages showing changes in the appearance of the leaf-cushions3 a leaf attached to a cushion in fig4 ,a4 7,slightly enlarged47 ,a portion of the cushion below the triangular leaf-scar often shows transverse gaping cracks or depressions 7fig4 #ahe1 ,c7 such as occur on a smaller scale on the older cushions of a ,fir twig 7fig4 #adj74 ,secondary thickening1 as in recent trees1 is not confined to the vascular cylinder but at an early stage1 frequently before there are any signs of secondary wood1 the outer region of the broad cortex becomes the seat of active cell-formation which results in the addition of a considerable thickness to the bark4 ,at a later stage of increase in girth1 the leaf-cushions are stretched apart and the original surface-features become obliterated by vertical cracks and by the exfoliation of the superficial tissues#bch4 ,some species of ,lepidodendron produced branches characterised by spiral or vertical series of scars2 these in older shoots were replaced by depressions having a diameter of several inches and comparable in appearance1 as also perhaps in manner of formation1 with the scars left on the stem of a ,kauri ,pine 7,agathis australis7#bci on the abscission of lateral branches by a natural process4 ,these shoots1 known as ,ulodendron1 are described in a subsequent section4 7,page #abh47 ,a fully-grown ,lepidodendron must have been an impressive tree1 probably of sombre colour1 relieved by the encircling felt of green needles on the young pendulous twigs4 ,the leaves of some species were similar to those of a fir while in others they resembled the filiform needles of the ,himalayan ,pine 7,pinus longifolia74 ,the occasional presence of delicate hyphae in the tissues of ,lepidodendron demonstrates susceptibility to fungal pests4 ,architecturally1 if one may use the term1 ,lepidodendron owed its power of resistance to the bending force of the wind to its stout outer bark formed of thick-walled elements produced by the activity of a cylinder of cortical meristem 7figs4 #adh1 #agb1 etc474 ,the vascular axis1 of insignificant diameter in proportion to the size of the stem 7figs4 #aeb1 #aec1 #agb1 #aha1 ,a71 must have played a subordinate part1 from a mechanical point of view1 as compared with the solid mass of wood of a ,pine or an ,oak4 ,within the compass of a text-book it is impossible1 even if it were desirable1 to include an account of the majority of the species of the widely distributed ,palaeozoic genus ,lepidodendron4 ,in spite of the great number of known species of this common member of ,carboniferous floras1 our knowledge of the type as a whole is deficient in many points1 and such information as we possess needs systematising and extending by comparative treatment based on a re-examination of available data4 ,in order to appreciate the meaning of certain external features characteristic of ,lepidodendron stems it is essential to have some knowledge of the internal structure4 ,a dual system of terminology has been unavoidably adopted for species of ,lepidodendron3 the majority of specific names have been assigned to fossils known only in the form of casts or impressions1 while petrified fragments1 which unfortunately seldom show the surface-features1 have received another set of names4 ,a glance at the older palaeobotanical literature reveals the existence of several generic designations1 which fuller information has shown to have been applied to lepidodendroid shoots deprived of some of their superficial tissues before fossilisation and differing considerably in appearance from the more complete branches of the same species#bdj4 ,it has in some instances been possible to correlate the two sets of specimens1 casts or impressions1 showing external features1 and petrified fragments4 ,we may reasonably expect that future discoveries will enable us to piece together as definite specific types specimens at present labelled with different names4 ,a well-preserved leaf-cushion of a ,lepidodendron--the most obvious distinguishing feature of the genus--is rhomboidal or fusiform and vertically elongated 7fig4 #adf1 ,c1 ,e2 fig4 #ahe1 ,c1 ,d73 in exceptional cases it may reach a length of #h cm4 and a breadth of #b cm4 ,the cushion as a whole represents a prominent portion of the stem or branch comparable with the elevation on the twig of a ,spruce ,fir and the leaf-base of a ,lycopodium 7cf4 fig4 #aba1 ,a1 lower portion7 which appears in a transverse section of a branch as a rounded prominence 7cf4 ,lycopodium1 fig4 #abe1 ,a and ,h74 ,disregarding differences in detail1 a typical ,lepidodendron leaf-cushion is characterised by a clearly defined smooth area often situated in the middle region 7fig4 #adf1 ,c1 s74 ,this is the leaf-scar or place of attachment of the base of the leaf which was cut off by an absciss-layer while the branch was comparatively young1 as in recent forest trees and in some species of ,ferns4 ,on the leaf-scar are three smaller scars or cicatricules1 the central one is circular or more or less triangular in outline1 the two lateral scars being usually oval or circular4 ,the central pit marks the position of the single vascular bundle which constituted the conducting tissue connecting the leaf with the main vascular system of the stem4 ,the two lateral scars 7figs4 #ade1 ,a1 p2 #adf1 ,c1 s2 #adg1 p7 represent the exposed ends of two strands of tissue1 the forked branches of a strand which pass from the middle cortex of the stem into the leaf2 this is known as the parichnos1 a name proposed by ,professor ,bertrand in #ahiabda4 ,the specimen shown in fig4 #ada shows the linear leaves attached to their respective cushions4 ,illustration3 ,,fig4 #ada4 ,lepidodendron ,sternbergii4 ,from a specimen in the ,british ,museum 7,no4 v4 #abce7 from the ,coal-,measures of ,shropshire4 7,nat4 size47 ,the lamina has a well-defined median keel on the lower surface and on either side a groove in which sections of petrified leaves have demonstrated the occurrence of stomata 7cf4 fig4 #adb74 ii4 ,leaves and ,leaf-cushions4 ,all ,lepidodendron leaves1 so far as we know1 possessed a single median vein only4 ,in some species1 as for example in ,lepidodendron longifolium ,brongn41 they have the form of long and slender acicular needles very similar to those of ,pinus longifolium2 in ,l4 ,sternbergii 7fig4 #ada7 they are much broader and shorter4 ,in external form as in internal structure it is often impossible to distinguish between the leaves of ,lepidodendron and ,sigillaria4 ,the distinguishing features enumerated by the late ,m4 ,renault cannot be employed1 with any great degree of confidence1 as diagnostic characters4 ,in transverse section the lamina of a ,lepidodendron leaf presents the same appearance as that of the ,sigillarian leaves represented in fig4 #adb4 ,near the base the free part of the leaf is usually sub-rhomboidal in section with short lateral wings1 a ventral keel and two stomatal grooves 7fig4 #adb1 ,a1 ,b1 g74 ,the form and arrangement of stomata are shown in fig4 #adc1 ,a1 which was drawn from a piece of a leaf shown in surface-view in a section lent to me by ,professor ,weiss4 ,it should1 however1 be pointed out that the leaf cannot be certainly identified with ,lepidodendron rather than with ,sigillaria1 but as the leaves of these two genera are constructed on the same plan the identification is of secondary importance4 ,illustration3 ,,fig4 #adb4 ,leaves of ,sigillaria in transverse section4 ,a1 ,a4 ,section in the ,manchester ,university ,museum 7,q4 #fca74 ,b1 ,c4 ,sections in ,dr ,kidston's ,collection4 ,the single xylem bundle consists of primary tracheae only1 at least in such laminae as have been identified as ,lepidodendroid4 ,surrounding the xylem strand occur delicate parenchymatous cells in some cases accompanied by darker and thicker-walled elements4 ,as in ,sigillaria1 the leaves of which are more fully described on page #baj1 a fairly broad sheath of wider and shorter scalariform or spiral transfusion tracheids surrounds the conducting strand 7figs4 #adb1 t2 #adc1 ,b1 ,c1 t74 ,as ,renault shows in the case of ,lepidodendron esnostense#bdb1 the small leaves of which are #ae-b mm4 broad at the base and several centimetres long1 the stomatal grooves and keel die out towards the apex when the lamina assumes a more nearly circular form 7fig4 #adc1 ,c74 ,illustration3 ,,fig4 #adc4 ,a4 ,stomata in surface-view 7,lepidodendron874 a1 parenchyma2 t1 transfusion tracheae2 x1 xylem4 7,manchester ,university ,collection ,r4 #gbc74 ,b1 ,c4 ,lepidodendron esnostense ,ren4 7,after ,renault47 ,the area of the cushion excluding the leaf-scar is spoken of by some writers as the field4 ,below the leaf-scar the kite-shaped cushion tapers to a gradually narrowing basal position3 in ,lepidodendron ,veltheimianum1 a species characteristic of ,lower ,carboniferous strata1 it is seen to be continuous1 as a ridge with sloping sides1 with a lower cushion 7fig4 #ahe74 ,below a leaf-scar the cushion frequently shows a pair of oval areas on which a fine pitting may be detected in well-preserved impressions1 these oval scars1 as seen in fig4 #ahe1 ,d1 are practically continuous at the upper end with the parichnos scars on the leaf-scar area2 this is explained by the fact that these infra-foliar scars also owe their existence to patches of lacunar1 aerenchymatous tissue in close connexion with the parichnos#bdc4 ,shortly before entering the base of the leaf-lamina the parichnos divides into two arms which diverge in the outer cortical region right and left of the vascular bundle1 and passing obliquely upwards they come close to the surface of the leaf-cushion just below the leaf-scar4 ,the diagram--fig4 #add1 ,b--shows a leaf-trace1 lt1 in the leaf-cushion1 as seen in a diagrammatic drawing of a vertical radial section of a stem1 the dotted lines1 p1 p1 show the two parichnos arms which are represented as impinging on the surface of the leaf-cushion at p1 and then bending upwards to pass into the leaf-base right and left of the vascular bundle or leaf-trace4 ,for convenience the arms of the parichnos are represented in one plane though actually in different vertical planes4 ,fig4 #add1 ,a1 shows the difference between a view of the original surface of a ,lepidodendron1 as at a1 where a leaf-cushion with a leaf-scar is seen1 and a view of an impression representing the outer cortex1 b1 a short distance below the surface4 ,the surface b1 in fig4 #add1 ,a1 corresponds to the face d-e in the diagrammatic longitudinal section fig4 #add1 ,b3 the outline of each cushion is clearly visible and in the centre is seen the leaf-trace1 lt1 with its parichnos4 ,the surface-features1 a 7fig4 #add1 ,a71 have been impressed on the rock1 c1 7fig4 #add1 ,b7 in which the specimen was entombed and by the removal of the cast of the stem1 that is the thickness b to e in fig4 #add1 ,b1 the form of the leaf-cushion is revealed4 ,the presence of the two infra-foliar parichnos scars at p 7fig4 #add1 ,a7 is explained by the diagram1 fig4 #add1 ,b1 p4 ,the relation of the parichnos to the oval scars below a ,lepidodendron leaf-cushion has been worked out in detail by ,weiss who shows that1 at least in some species1 the two arms do not bend downwards as shown in the diagram1 fig4 #add1 ,b1 but pursue a straight gradually ascending course as seen in fig4 #ade1 ,a4 ,just below the leaf-scar region of the cushion each arm comes into association with a group of lacunar1 aerenchymatous tissue1 such as occurs in the roots of certain ,mangrove plants1 and it is this aerenchyma which is exposed on the two oval depressions below the leaf-scar4 ,the structure of this aerenchyma is shown in fig4 #ade1 ,b2 it consists in this species 7,l4 ,hickii ,wats47 of stellate cells which would constitute an efficient aerating system4 ,probably1 as ,weiss suggests1 these patches of aerenchyma were originally covered by an epidermis provided with stomata1 and it is owing to the destruction of this superficial layer that the two oval scars often form a prominent feature on ,lepidodendron leaf-bases#bdd4 ,the diagram reproduced in fig4 #add1 ,b1 may be taken as practically correct1 as the patches of aerenchyma described by ,weiss do not differ essentially from the parichnos tissue4 ,illustration3 ,,fig4 #add4 ,lepidodendron ,veltheimianum ,sternb4 ,a4 ,leaf-cushion and leaf-scar seen in surface-view at a2 on the rest of the specimen a slightly lower surface is exposed4 7,after ,stur47 ,b4 ,diagrammatic longitudinal section to explain the differences between its two surfaces a and b shown in fig4 ,a4 ,the shaded portion c represents the rock matrix1 the surfaces ab1 ed1 mark the outer and inner edge of the outer portion of the bark of the ,lepidodendron stem4 lt1 leaf-trace2 p1 p1 parichnos4 ,illustration3 ,,fig4 #ade4 ,a4 ,diagrammatic surface-view and longitudinal section of a ,lepidodendron leaf-cushion4 ,b4 ,aerenchyma below the leaf-scar4 7,after ,f4 ,e4 ,weiss47 ,the parichnos scars are shown on the leaf-scar and cushion in fig4 #adf1 ,c4 ,in the lower leaf-cushion shown in fig4 #adf1 ,e1 the infra-foliar parichnos scars1 p1 are clearly seen1 but the preservation of the leaf-scar is not sufficiently good to show them on that part of the fossil4 ,in the upper cushion 7fig4 #adf1 ,e7 the position of the parichnos arms is shown on the leaf-scar1 but the infra-foliar parichnos scars are hidden by two small spiral shells4 ,the genus ,spirorbis1 to which these shells are referred1 appears to have persisted from the ,silurian epoch to the present day4 ,the comparatively frequent occurrence of ,spirorbis shells on the leaves and other parts of ,palaeozoic plants1 has recently been dealt with in a paper by ,barrois#bde who discusses in detail the habitats of these small animals from the point of view of the conditions under which the plants were preserved4 ,in a note by ,malaquin appended to ,barrois' paper the belief is expressed that ,spirorbis lived on pieces of ,palaeozoic plants which lay under water4 ,the fact that with one exception all the ,spirorbis shells on the specimen of ,lepidodendron1 of which two leaf-cushions are shown in fig4 #adf1 ,e1 occur on the large parichnos scars on the cheeks of the cushions1 suggests the possibility that the escape of gases from the parichnos tissue may have rendered the position attractive to the ,spirorbis4 ,it can hardly be accidental that the shells occur on the parichnos strands4 ,this fact recalls the view held by ,binney#bdf and accepted with favour by ,darwin#bdg that ,lepidodendron and other coal-forest trees may have lived with the lower parts of the stems in sea water4 ,above the leaf-scar is a fairly deep triangular or crescentic pit 7fig4 #adf1 ,c1 l7 known as the ligular pit from the occurrence on younger shoots of a delicate organ like the ligule of ,isoetes 7fig4 #acb7 embedded in a depression in the upper part of the leaf-cushion4 ,the ligule was first figured in ,lepidodendron by ,solms-,laubach#bdh and described in ,english material by ,williamson under the name of the adenoid organ#bdi4 ,in some ,lepidodendron stems a second triangular depression may occur above the ligular pit1 the meaning of which is not clear3 this has been called the triangulum by ,potoni#bej4 ,stur#bea suggested that it may represent the position occupied by a sporangium in ,lepidodendron cones4 ,it is important to remember that as a branch increases in girth the leaf-cushions are capable of only a certain amount of growth3 when the limit is reached they are stretched farther apart and thus the narrow groove which separates them is converted in older stems into a comparatively broad and flat channel1 thus altering the surface characters4 ,illustration3 ,,fig4 #adf4 ,lepidophloios and ,lepidodendron leaf-cushions4 ,a1 ,b1 ,d1 ,f1 ,g1 ,h1 ,i4 ,lepidophloios4 7,fig4 ,a should be reversed47 ,c1 ,e4 ,lepidodendron aculeatum4 ,a1 ,b4 ,from a specimen in the ,sedgwick ,museum1 ,cambridge 7leaf-cushion #c cm4 broad74 ,c4 ,from a specimen in the ,sedgwick ,museum1 ,cambridge 7leaf-cushion #d cm4 long74 ,d4 ,from a section in the ,cambridge ,botany ,school ,collection4 ,e4 ,from a specimen in the ,bunbury ,collection1 ,cambridge ,botany ,school1 showing ,spirorbis shells 7leaf-cushion #b cm4 long74 ,f4 ,from a section in the ,williamson ,collection1 ,british ,museum ,no4 #a1 #igc4 ,g1 ,h1 ,i4 ,from sections in the ,cambridge ,botany ,school ,collection4 ,another feature worthy of notice in reference to the leaf-cushions of ,lepidodendron is the occurrence in rare instances of alternate zones of larger and smaller cushions4 ,this variation in the size of the leaf-cushions is by no means uncommon in the closely allied genus ,sigillaria2 in ,lepidodendron it has been described by ,potoni#beb in ,l4 volkmannianum and more recently by ,mr ,leslie and myself#bec in a ,south ,african species ,l4 vereenigense4 ,owing to the natural exfoliation of the superficial layers of the outer bark at a certain stage in the growth of the plant1 or in some instances no doubt as the result of post-mortem decay1 which destroys the delicate cells of the meristematic zone in the outer cortex1 isolated leaf-cushions and strips of the external surface are occasionally met with as carbonised impressions4 ,the appearance presented by a ,lepidodendron stem which has been deprived of its superficial tissues may be dealt with more intelligibly after we have become familiar with the anatomical characters4 iii4 ,lepidophloios4 ,before proceeding further with the genus ,lepidodendron a short account may be intercalated of the external features of a lepidodendroid type of stem which it is customary to describe under a distinct generic title ,lepidophloios4 ,this name is convenient for diagnostic purposes though it seems clear that apart from the form of the leaf-cushion 7fig4 #adf1 ,a7 we are at present unable to recognise any well-defined differences between the two forms ,lepidodendron and ,lepidophloios4 ,for general purposes the name ,lepidodendron will be used as including plants possessing leaf-cushions of the type already described as well as those with the ,lepidophloios form of cushion4 ,the generic name ,lepidophloios was first used by ,sternberg#bed for a ,carboniferous species which he had previously described as ,lepidodendron laricinum4 ,in #ahde ,corda#bee instituted the name ,lomatophloios for specimens possessing the same external characters as those for which ,sternberg had chosen the name ,lepidophloios4 ,the leaf-cushions of ,lepidophloios differ from those of the true ,lepidodendron in their relatively greater lateral extension 7cf4 fig4 #adf1 ,a and ,c71 in their imbricate arrangement and in bearing the leaf1 or leaf-scar1 at the summit4 ,in some species referred to ,lepidophloios the cushions are however vertically elongated and in this respect similar to those of ,lepidodendron3 an example of this type is afforded by ,lepidophloios ,dessorti a ,french species described by ,zeiller#bef4 ,in younger branches the cushions may be directed upwards having the leaf-scar at the top2 but in the majority of specimens the cushions are deflexed as in figs4 #adf1 ,d2 #afj1 ,a4 ,the shoot of ,lycopodium dichotomum shown in fig4 #aba1 ,b1 with the leaves in the reversed position bears a close resemblance to a branch of ,lepidophloios4 ,the photograph of ,lepidophloios scoticus ,kidst4#beg reproduced in fig4 #afj1 ,a1 illustrates the dichotomous branching of the stem and the form of the cushions with the leaf-scars pointing downwards4 ,in the fertile branch of the same species shown in fig4 #afj1 ,b1 the leaf-scars face upwards4 ,in most species the cushions are simply convex without a median keel1 but in some cases a median ridge divides the cushion into two cheeks as in the genus ,lepidodendron4 ,the leaf-scar bears three small scars1 the larger median scar marking the position of the leaf-trace1 while the lateral scars are formed by the two arms of the parichnos3 in some examples of deflexed cushions1 though not in all1 a ligular pit occurs on the cushion a short distance above the leaf-scar4 ,the drawing reproduced in fig4 #adf1 ,a1 showing the leaf-scar on the upper edge of the cushion should have been reversed with the leaf-scars pointing downwards4 ,this figure represents part of the surface of a specimen consisting of the outer cortex of a stem with leaf-cushions #c cm4 broad4 ,the thickness of this specimen is #d cm43 a section through the line ab is represented in fig4 #adf1 ,d 7reproduced in the correct position1 with the leaf-scars1 sc1 pointing downwards73 internal to the cushions is a band of secondary cortex 7the shaded strip on the outer edge of the section7 which was formed on the outside of the phellogen4 ,the phellogen is a cylinder of actively dividing cells in the outer part of the cortex of the stem1 often spoken of as the cork-cambium or cortical meristem1 which produces a considerable amount of secondary cortical tissue on its inner face and a much smaller amount towards the stem surface4 ,this delicate cylinder frequently forms a natural line of separation between the outer shell of bark and the rest of the stem4 ,in the specimen before us1 the thin-walled cells of the phellogen were ruptured before petrification and the outer shell of bark was thus separated as a hollow cylinder from the rest of the stem3 this cylinder was then flattened1 the two inner surfaces coming into contact4 ,fig4 #adf1 ,d1 represents a section of one half of the thickness of the flattened shell4 ,this separation of the outer cortex1 and its preservation apart from the rest of the stem1 is of frequent occurrence in fossil lycopodiaceous stems4 ,the flattened outer cortical shell of a ,lepidophloios1 specifically identical with that shown in fig4 #adf1 ,a and ,d1 was erroneously described by ,dr ,c4 ,e4 ,weiss in #ahha as a large lepidodendroid cone#beh4 ,fig4 #adf1 ,b1 affords a view of the inner face of the specimen of which the outer surface is seen in fig4 #adf1 ,a3 the surface shown in the lower part of the drawing1 on which the boundaries of the cushions are represented by a reticulum1 corresponds to the inner edge of the strip of secondary cortical tissue represented by the vertically shaded band in fig4 #adf1 ,d4 ,the shaded surface in fig4 #adf1 ,b1 represents a slightly deeper level in the stem which corresponds to the outer edge of the vertically shaded band of fig4 #adf1 ,d3 the narrow tapered ridges 7fig4 #adf1 ,b7 represent the leaf-traces passing through the secondary cortex1 and the fine vertical shading indicates the elongated elements of which this strip of secondary cortex is composed4 ,in the longitudinal section diagrammatically reproduced in fig4 #adf1 ,d1 cut along the line ab of fig4 #adf1 ,a1 the parenchymatous tissue of the stout cushions has been partially destroyed1 as at a2 at s is seen the section of a ,stigmarian rootlet which has found its way into the interior of a cushion4 ,each leaf-trace is accompanied by a parichnos strand as in the true ,lepidodendron2 at the base of the leaf-cushion the parichnos branches into two arms which diverge slightly right and left of the leaf-trace1 finally entering the base of the leaf lamina as two lateral strands 7fig4 #adg1 p74 ,at one point in fig4 #adf1 ,d the section has shaved a leaf-trace represented by a black patch resting on the parichnos just above the line ef1 but it passes through one of the parichnos arms p which debouches on to the leaf-scar sc at p4 ,had the section been cut along the line cd of fig4 #adf1 ,a the leaf-trace would have been seen in a position similar to that occupied by the parichnos p in fig4 #adf1 ,d4 ,illustration3 ,,fig4 #adg4 ,lepidophloios leaf-cushion in tangential section4 7,from a section in the ,williamson ,collection1 ,british ,museum1 ,no4 #aigc47 ,fig4 #adg1 ,a1 affords a good example of a tangential section through a ,lepidophloios leaf-cushion1 #a cm4 broad1 like that represented in fig4 #adf1 ,a1 showing the vascular bundle lt1 the two parichnos strands1 p1 composed of large thin-walled cells 7cf4 ,isoetes1 fig4 #acc1 ,h1 ,i71 and the ligular pit near the upper edge of the section enclosing the shrunken remains of the ligule 7fig4 #adg1 ,b1 l74 ,sidenote3 ,,lepidodendron ,fig4 #adg1 ,b1 shows the form of the tangentially elongated leaf-cushions of ,lepidophloios and their spiral disposition4 ,fig4 #adf1 ,f1 represents a section similar to that shown in figs4 #adg1 ,a and ,b1 but in this case the leaf-trace1 lt1 and the parichnos strands1 p1 lie in a cavity formed by the destruction of some of the leaf-cushion tissue4 ,it is worthy of notice that the parichnos cells have resisted decay more successfully than the adjacent tissue of the cushion4 ,the diagrammatic sketches reproduced in fig4 #adf1 ,h and ,i1 were made from a transverse section similar to one originally figured by ,williamson#bei3 fig4 #adf1 ,h1 corresponding in position to the line gh in fig4 #adf1 ,a1 passes through the ligular pit1 l1 and cuts across the parichnos in the act of branching2 the leaf-trace passes outwards beyond the ,y-shaped parichnos strand4 ,in the other section1 fig4 #adf1 ,i1 the parichnos is shown in a horizontal plane and the leaf-trace1 lt1 appears in oblique transverse section4 ,in both sections and in fig4 #adf1 ,g the shaded band at the base represents the secondary cortical tissue external to the phellogen4 ,the transverse section represented in fig4 #adf1 ,g1 shows in the left-hand cushion1 a1 the exit of the two parichnos arms and the leaf-trace between them3 it illustrates also the various forms assumed by lepidodendroid leaf-cushions when cut across at different levels4 iv4 ,the ,anatomy of ,lepidodendron vasculare ,binney#bfj4 ,figs4 #adh-aee1 #afh1 ,a4 ,in the earlier literature dealing with the anatomy of ,lepidodendron and ,sigillaria the presence or absence of secondary vascular tissue was made the criterion of generic distinction and the distinguishing feature between the classes ,pteridophytes and ,gymnosperms1 ,lepidodendron being relegated to the former class because it was supposed to have no power of forming secondary wood1 while ,sigillaria1 characterised by a considerable development of such tissue1 was classed by ,brongniart and afterwards by ,renault as a ,gymnosperm4 ,binney#bfa in #ahfe recognised that the two types of stem pass into one another1 but it was ,williamson#bfb who provided complete demonstration of the fallacy of the ,brongniartian view4 ,these two undoubted ,pteridophytes agree very closely in anatomical structure and both are now recognised as arborescent genera of ,lycopodiaceous plants4 ,in a paper published by ,lomax and ,weiss in #aijebfc a specimen is described from the ,coal-,measures of ,huddersfield1 in which a decorticated stem with the anatomical characters of ,binney's ,sigillaria vascularis gives off a branch having the anatomical structure which it has been customary to associate with the species ,lepidodendron selaginoides1 so-called by ,sternberg and founded by him on impressions showing well-preserved external characters4 ,in #ahfb ,binney#bfd described petrified specimens of vegetative shoots from the ,lower ,coal-,measures of ,lancashire under the names ,sigillaria vascularis and ,lepidodendron vasculare4 ,these were afterwards recognised as different states of the same species4 ,a few years after the publication of ,binney's paper ,carruthers#bfe identified ,binney's species ,lepidodendron vasculare with ,sternberg's ,l4 selaginoides4 ,the evidence on which this identification rests has not been stated1 but many writers have retained this specific designation for the well-defined type of anatomical structure first described by ,binney as ,l4 vasculare4 ,the use of the specific name selaginoides is1 however1 open to objection4 ,the species ,lepidodendron selaginoides1 as pointed out by ,kidston#bff1 is probably identical with the plant which ,brongniart had named ,l4 ,sternbergii before the institution of ,sternberg's species1 and we are not in possession of convincing evidence as to the connection of ,l4 ,sternbergii 7 ,l4 selaginoides7 with specimens possessing the anatomy of ,binney's type4 ,binney's designation is therefore retained for the anatomical type described in the following pages#bfg4 ,the most detailed account hitherto published of the anatomy of ,lepidodendron vasculare is that by the late ,m4 ,hovelacque#bfh1 based on material from the ,lower ,coal-,measures of ,england4 ,illustration3 ,,fig4 #adh4 ,lepidodendron vasculare ,binney4 ,a4 ,transverse section4 7,based on a section #be cm4 in diameter1 in the ,cambridge ,botany ,school ,collection47 ,b4 ,longitudinal section4 7,drawn from a section in ,dr ,kidston's ,collection47 ,the small shoot1 represented somewhat diagrammatically in fig4 #adh1 ,a1 illustrates the anatomical features of a typical example of the species3 the shoot has a diameter of #be cm4 and its central cylinder 7x-sc7 is #be mm4 in width4 ,noticeable features are 7i7 the small size of the central cylinder 7or stele7 in proportion to the diameter of the branch1 7ii7 the production at a comparatively early stage of growth of a zone of secondary wood1 x1 which gradually assumes the form of a complete cylinder of unequal breadth1 surrounding the primary xylem1 x1 7iii7 the formation of a secondary cortical tissue by a meristematic cylinder 7phellogen1 pl7 situated close to the leaf-cushion region of the outer cortex4 ,on the outer edge the stele consists of narrow tracheae some of which show in longitudinal section the spiral form of thickening characteristic of most protoxylem elements3 towards the centre of the stele the diameter of the tracheae gradually increases and parenchymatous cells become associated with the elongated scalariform elements4 ,in the central region the stele is composed of parenchymatous tissue arranged in vertical series of short cells1 interspersed with short tracheae distinguished by the greater thickness of their walls and by their scalariform and reticulate thickening bands4 ,some of these short tracheae are shown in vertical section in fig4 #adi1 ,b3 the fine and broken lines connecting adjacent thickening bands probably represent the remains of the original wall4 ,these delicate bands1 which have been figured in various species of lepidodendroid plants#bfi1 are worthy of notice in connexion with the recent work of ,mr ,gwynne-,vaughan#bgj who has shown that in many recent ferns the scalariform bands in the xylem elements are not connected by a thin pit-closing membrane1 but are separated from one another by open spaces4 ,in the ,lepidodendron tracheae we seem to have a stage in which the intervening membrane is in process of absorption4 ,it is1 however1 possible that the threads may be the result of contraction and splitting of the membrane during drying or decay4 ,illustration3 ,,fig4 #adi4 ,lepidodendron vasculare4 a1 immature tracheae2 m1 meristem2 mr1 medullary ray2 x1 xylem4 ,a4 ,longitudinal section through the edge of the secondary wood4 ,b4 ,short tracheae in the centre of the stele4 7,from a specimen from the ,halifax ,hard bed in ,dr ,kidston's ,collection47 ,the stele of ,lepidodendron vasculare1 before the addition of any secondary xylem1 may be described as a protostele1 a term originally proposed by ,professor ,jeffrey#bga1 in which the central part of the conducting strand of xylem elements has been converted into rows of parenchyma and short tracheids1 the latter being better adapted to storage than to conduction4 ,it is probable that this type of stelar anatomy1 which distinguishes ,l4 vasculare from other species1 represents a comparatively primitive arrangement forming a transition between the stele of ,l4 esnostense1 which consists of a solid rod of tracheids1 and the stele of ,l4 ,harcourtii 7fig4 #agi1 ,a7 and other species in which the xylem forms a cylinder enclosing a large parenchymatous pith4 ,parenchymatous cells occur in contact with the outer edge of the xylem-cylinder some of which are distinguished by an irregular reticulate pitting4 ,the tangential section represented in fig4 #adh1 ,b1 illustrates the appearance of a shoot of ,l4 vasculare in which no secondary xylem is present3 the central strand of tissue consists of the parenchyma abutting on the xylem with several leaf-traces 7lt7 passing upwards in an almost vertical course from the outer edge of the stele4 ,the secondary xylem 7fig4 #adh1 ,a1 x7 consists of radially arranged scalariform tracheae with associated rows of parenchymatous cells which form medullary rays 7fig4 #adi1 mr74 ,leaf-traces pass through the medullary rays in the secondary xylem cylinder in a direction at right angles to the primary xylem stele from which they are given off1 but at the outer edge of the secondary xylem they bend suddenly upwards and for a time follow a steep and almost vertical course4 ,in well-preserved longitudinal sections the outermost secondary xylem tracheae are seen to be succeeded by a few narrow and vertically elongated elements 7fig4 #adi1 ,a1 a71 which represent young unlignified tracheae3 these are followed by shorter parenchymatous cells 7m7 forming part of a meristematic zone from which the secondary xylem receives additions4 ,returning to fig4 #adh1 ,a2 the zone of secondary wood1 x1 composed of scalariform tracheids and medullary rays1 is succeeded by a few layers of parenchymatous cells and beyond this is a broader zone1 sc1 to which the term secretory zone has been applied#bgb2 this is made up of small parenchymatous cells varying in size and of larger spaces which appear to have been formed by the disorganisation of thin-walled elements4 ,the whole zone presents a characteristic appearance due to the association of small cells1 large clear spaces1 and a certain amount of dark-coloured material suggestive of tissue disorganisation and secreted products4 ,the anatomical characters of the secretory zone are shown in the photograph1 fig4 #afh1 ,a1 sc4 ,several leaf-traces are seen in transverse section in the secretory zone 7black dots in fig4 #adh1 ,a1 sc2 fig4 #aed1 ,c1 lt73 each trace consists of a strand of narrow tracheae accompanied by a few encircling layers of small parenchymatous cells4 ,as a trace continues its steeply ascending course through the secretory zone1 it becomes associated with a strand of that tissue and assumes the form of a collateral vascular bundle1 the outer part of which does not consist of typical phloem but of shorter elements derived from the secretory zone4 ,beyond the secretory zone we find a more homogeneous tissue composed of parenchymatous elements slightly extended tangentially 7figs4 #adh1 ,a1 c2 fig4 #afh1 ,a1 c72 this is spoken of as the inner cortical region4 ,in the great majority of sections of ,l4 vasculare as of other species of the genus1 the broader middle cortex 7fig4 #adh1 c7 is occupied by mineral matter1 introduced subsequent to decay of the tissue2 or it is represented by patches of delicate tissue composed of loosely arranged parenchymatous cells varying considerably in size and shape1 some being small1 oval or polygonal elements while others have the form of sinuous hypha-like tubes4 ,in this middle cortical region may be seen leaf-traces passing outwards in an almost horizontal course 7fig4 #adh1 ,a1 lt73 after leaving the inner cortex the leaf-traces bend somewhat abruptly outwards to follow a more direct path through the middle and outer cortex4 ,the ring of tissue1 s1 seen in the middle cortex of fig4 #adh1 ,a1 belongs to a ,stigmarian rootlet4 ,the outer cortex 7fig4 #adh1 ,a and ,b1 c7 consists of homogeneous parenchyma which is stronger and more resistant to decay than the looser middle cortex4 ,the leaf-traces1 as shown in fig4 #adh1 ,b1 pass through this region in a rather steeply ascending direction3 each is seen to be enclosed by a space originally occupied by a strand of middle cortical tissue which accompanies lepidodendroid leaf-traces on their under side and has already been described as the parichnos1 7pp4 #ig1 #ajj-ajc2 figs4 #adf1 #adg74 ,the surface of the stem shown in section in fig4 #adh1 ,a1 is composed of broad leaf-cushions4 ,a single leaf-trace with its parichnos passes into each cushion1 but in the neighbourhood of the base of a cushion the parichnos bifurcates 7cf4 fig4 #adf1 ,h1 ,i7 and the arms diverge slightly to the right and left finally passing beyond the cushion into the lamina of the leaf1 their position being shown1 as already explained1 by the two small lateral scars on the leaf-scar area4 ,the diagrammatic sketch of a radial longitudinal section through a leaf-cushion represented in fig4 #aej illustrates the relation of the leaf-trace to the leaf-cushion4 ,the trace consists of xylem1 x1 above and a strand of the secretory zone1 st1 below2 the parichnos tissue was originally present on the under side of the leaf-trace at a4 ,the external surface1 bc1 marks the limit of the leaf-scar through the middle of which passes the vascular strand lt4 ,the lower gap a has been formed by the tearing of thin-walled cells of the phellogen1 the meristematic tissue from which a considerable amount of secondary cortical tissue or phelloderm has been produced at pd4 ,on the outside of the cushion1 c1 the cells are somewhat crushed and distinguished by their darker colour from the bulk of the parenchymatous tissue d4 ,this section also illustrates another characteristic feature of ,lepidodendron1 namely the presence of a ligule and a ligular pit3 the former is represented by a carbonised patch of tissue and the latter extends from the surface of the cushion at b1 just above the leaf-scar1 almost to the level of the leaf-trace1 lt4 ,a comparison of this section with figs4 #adf and #adg will make clear the relation of the several parts of the cushion and leaf-scar4 ,the gaps gg1 seen in fig4 #adh1 ,a and ,b1 mark the position of the delicate meristematic zone or phellogen which arises close to the bases of the leaf-cushions2 the phellogen has already produced a few rows of radially disposed elements1 represented by short radial lines in the drawing1 which constitute secondary cortical tissue4 ,illustration3 ,,fig4 #aej4 ,lepidodendron vasculare4 ,leaf-cushions in longitudinal section4 7,from a specimen in ,dr ,kidston's ,collection47 ,in older shoots the amount of the secondary cortical tissue developed on the inner side of the phellogen is considerable 7cf4 figs4 #aeb1 #aec74 ,the structure of the cortex of a shoot in which secondary growth1 both in the stele and in the outer cortex1 has progressed further than in the specimen shown in fig4 #adh is represented in fig4 #aea4 ,illustration3 ,,fig4 #aea4 ,lepidodendron vasculare4 ,an older stem than that shown in fig4 #adh4 7,from a section in the ,manchester ,museum4 ,no4 #cea47 ,the section 7fig4 #aea1 ,a7 measures #g #ch cm4 in diameter2 the primary xylem is surrounded by a fairly broad cylinder of secondary wood 7fig4 #aea1 ,e1 x and x74 ,the almost smooth surface of the primary wood 7fig4 #aea1 ,e1 x7 is succeeded by the secondary xylem1 x1 characterised at its inner edge by the tapered ends of the radial rows of scalariform tracheids between which occur several delicate parenchymatous cells 7fig4 #aea1 ,e1 a74 ,the occurrence of such isodiametric elements1 often exhibiting a delicate spiral thickening band1 is a characteristic feature of the boundary between primary and secondary wood in lepidodendroid stems4 ,the secondary wood is penetrated by numerous medullary rays and in some of them are seen strands of narrow spirally thickened tracheae--the leaf-traces--which are in organic continuity with the exarch protoxylem of the primary wood4 ,the leaf-traces are oval and mesarch4 ,the space1 c1 7fig4 #aea1 ,a7 originally occupied by the delicate middle cortex1 is succeeded by a shell of outer cortex composed chiefly of secondary tissue 7phelloderm1 pd7 passing towards the inner boundary of this region into the primary outer cortex g 7fig4 #aea1 ,a and ,c74 ,the radially disposed elements which make up the bulk of the phelloderm are associated with concentric rows of secretory strands1 represented by tangentially arranged dots in fig4 #aea1 ,a3 on the outer edge of the phelloderm a few patches of primary cortex are still preserved1 as at c1 fig4 ,a4 ,one of these is shown on a larger scale in fig4 ,b2 at m the phelloderm is interrupted by a gap beyond which the cells have thinner walls and show signs of recent division2 this is probably the position of the phellogen4 ,the tissue b1 fig4 #aea1 ,b1 consists of secondary cortex succeeded beyond d by the parenchymatous tissue of the leaf-cushion1 in which the remains of a ligule1 l1 are seen in the ligular pit4 ,this section corresponds in position to a line drawn across fig4 #aej at the level of b4 ,in this specimen we have two kinds of secondary cortical tissue3 that formed external to the phellogen1 from m to d in fig4 #aea1 ,b1 is less in amount than that produced internal to the phellogen4 ,we cannot make any satisfactory statement as to the nature of this secondary tissue1 whether or not any of it agreed in composition with the cork which is usually formed external to the phellogen in recent plants4 ,as the stem of a ,lepidodendron grew in girth the leaf-cushions became separated by intervening depressions composed of the secondary cortex formed external to the phellogen1 but at a later stage the cushions were thrown off1 leaving the outer edge of the phelloderm as the superficial tissue4 ,this exposed tissue became fissured as growth and consequent stretching continued1 producing the appearance seen on the surface of the still older stem represented in fig4 #aec4 ,the inner edge of the phelloderm seen at e in fig4 #aea1 ,c1 passes suddenly into the inner primary region of the outer cortex 7fig4 #aea1 ,a and ,c1 g7 which comprises two types of parenchymatous tissue1 patches of isodiametric cells1 g1 g1 alternating with radially arranged areas consisting of tangentially elongated elements 7fig4 ,c1 f1 f2 fig4 ,d7 which extend as wedges into the phelloderm4 ,the longitudinal section represented in fig4 #aeb1 ,b1 shows an equal bifurcation of a stem in which no secondary xylem is present2 in the lower part of the section the xylem and the outgoing leaf-traces are seen in radial section and at the upper end of each arm the leaf-traces alone1 lt1 are exposed1 as in fig4 #adh1 ,b4 ,it is interesting to notice the large amount of phelloderm which has been produced in the fork of the branch1 at pd1 where greater strength is required4 ,illustration3 ,,fig4 #aeb4 ,lepidodendron vasculare4 ,sections of dichotomously branched shoot4 ,a4 ,from a section 7#aje #i cm47 in the ,cambridge ,botany ,school ,collection4 ,b4 ,from a section 7#h cm4 long7 in the ,cambridge ,collection4 ,the section represented diagrammatically in fig4 #aeb1 ,a1 has lost the outermost part of the cortex together with the leaf-cushions2 it consists largely of secondary cortex composed of radially disposed phelloderm cells and tangentially placed secretory strands 7represented by the discontinuous black lines in the drawing73 the dotted region in the central part of the axis is composed of primary cortical parenchyma1 and the two spaces surrounding the steles contain portions of the lacunar middle cortex4 ,each stele possesses a narrow crescentic zone of secondary xylem2 the amount is greater in the case of the right-hand stele1 of which a small piece is shown on a larger scale2 the striking contrast in size between the outer and more internal secondary tracheae is no doubt the expression of some unfavourable condition of growth4 ,the position of the secretory zone beyond the secondary xylem is shown at sc1 fig4 #aeb1 ,a4 ,illustration3 ,,fig4 #aec4 ,lepidodendron vasculare4 7,from a specimen 7#af #ge cm47 in the ,manchester ,museum47 ,an example of a large and partially decorticated stem is afforded by the specimen 7#af #ge cm47 shown in fig4 #aec4 ,the irregularly ribbed surface is formed of rather thick-walled phelloderm1 in which occur tangentially arranged rows of secretory strands4 ,the tapered form of the secondary cortex as it abuts internally on the primary cortex is shown very clearly in the drawing 7cf4 fig4 #aea1 ,c74 ,the stele in this much older stem consists mainly of secondary wood4 ,illustration3 ,,fig4 #aed4 ,lepidodendron vasculare4 ,shoot 7#bh cm4 diam47 with two steles4 7,from a specimen from ,halifax in the ,williamson ,collection1 ,british ,museum1 ,no4 #cdj47 ,an interesting example of a small shoot1 the largest diameter of which is #bh cm41 is shown in fig4 #aed1 ,a3 the section was cut a short distance above the bifurcation of the stele into two approximately equal branches4 ,the outer part of the cortex consists of phelloderm1 pd1 with the usual rows of secretory tracts1 and primary outer cortex g2 the middle cortex is represented by patches of parenchyma with a few leaf-traces4 ,to one of the steles1 s 7fig4 #aed1 ,a71 a crescent-shaped band of secondary xylem has been added2 the other stele1 ,s1 possesses no fully developed secondary elements4 ,fig4 #aed1 ,b and ,c1 illustrates the anatomical features immediately external to the primary xylem of the smaller stele1 s4 ,the comparatively broad band of radially disposed parenchyma1 m1 is connected with the outermost elements of the xylem by a few rather dark and small crushed parenchymatous cells4 ,the band m1 which we may speak of as the meristematic zone1 clearly consists of cells in a state of division2 it is in this region that the secondary xylem is produced4 ,beyond the leaf-trace1 7fig4 #aed1 ,c1 lt71 occurs a portion of the secretory zone1 some of the smaller cells of which show signs of disorganisation2 but most of this tissue has been destroyed 7fig4 #aed1 ,b1 sc74 ,the outer edge of the secretory zone is shown in fig4 #aed1 ,d abutting on the cells of the inner cortex1 c4 ,the leaf-trace shown in the inner cortex in fig4 #aed1 ,b illustrates the more oval or tangentially extended form of the xylem in this region1 in contrast to the more circular outline which it exhibits on the inner side of the secretory zone4 ,illustration3 ,,fig4 #aee4 ,lepidodendron vasculare4 ,outer edge of secondary xylem3 m1 meristematic zone2 mr1 medullary ray4 7,drawn from the section shown in fig4 #afh1 ,a74 ,the transverse section1 part of which is reproduced in fig4 #afh1 ,a1 illustrates a characteristic feature1 namely the juxtaposition of the outermost tracheae of the secondary xylem and much smaller cells of the meristematic zone4 ,this is seen in fig4 #aee1 which shows a small piece of fig4 #afh1 ,a1 on a larger scale4 ,in plants with a normal cambium the segments cut off from the initial layer fit on to the elements of the xylem or phloem to which they are to form additions1 but in ,lepidodendron it seems to be a general rule to find each of the most external lignified elements abutting on a group of two or three much smaller cells4 ,it is difficult to believe that the meristem shown in fig4 #aee1 m1 could produce secondary xylem elements equal in size to those already formed3 in all probability had growth continued there would have been a marked difference between the size of the secondary tracheids1 as in fig4 #aeb1 ,a1 x1 where there was no doubt some cause which interfered with normal cambial activity4 ,this disparity in size between the secondary xylem elements and the adjacent parenchymatous tissue of the meristematic zone is by no means exceptional and may be described as the general rule4 ,it is at least certain that in ,lepidodendron vasculare1 as in other species1 the secondary xylem was succeeded by a broad band of parenchymatous tissue1 from which new tracheae and medullary-ray elements were produced1 and not by a narrow cambium such as occurs in recent plants4 v4 ,lepidodendron stems as represented by casts and impressions of partially decorticated specimens4 ,the differentiation of the outer cortex of a ,lepidodendron into comparatively thin-walled and more resistant tissue has been the cause of unequal decay and the consequent formation of shrinkage cavities4 ,in addition to the unequal resisting power of contiguous tissues1 another important factor in determining the nature of casts and impressions is the existence of the cylinder of delicate cells in the outer cortex of stems and branches4 ,as already pointed out1 this meristematic cylinder or phellogen constitutes a natural line of separation1 as in the case of the cambium layer between the wood and the external tissues in a fresh ,sycamore twig4 ,the result of the separation of an outer shell of bark from the rest of the stem and the results of unequal decay in the more superficial tissues1 have necessarily led to the preservation of the same specific type under a variety of forms4 ,our knowledge of the anatomy of ,lepidodendron stems enables us to recognise in fossils of very different appearance specimens in various conditions of preservation of one and the same type4 ,such names as ,knorria1 ,bergeria and ,aspidiaria are examples of generic titles instituted before any adequate knowledge of ,lepidodendron anatomy was available4 ,differences in age as well as different degrees of decortication have contributed in no small measure to the institution of generic and specific names which more recently acquired knowledge has shown to be superfluous4 a4 ,knorria4 ,the designation ,knorria1 after a certain ,g4 ,w4 ,knorr of ,nrnberg1 was proposed by ,sternberg in #ahbfbgc for casts of ,palaeozoic stems of a type figured more than a century earlier by ,volkmann#bgd4 ,goeppert1 in his earlier works1 published drawings of fossil stems which he referred to ,sternberg's genus3 one species he at first called ,didymophyllum ,schollini4 ,he afterwards#bge described some specimens which showed that the features characteristic of ,knorria may occur on partially decorticated stems with leaf-cushions of the true ,lepidodendron type4 ,his specimens1 preserved in the ,breslau ,museum1 demonstrate the accuracy of his drawings and conclusions4 ,goeppert1 and after him ,balfour#bgf1 drew attention to the different appearances presented by branches of ,araucaria imbricata when preserved with the surface intact and after partial decortication1 as illustrating possible sources of error in the determination of fossil stems4 ,although it is now a well-established fact that fossils bearing the name ,knorria are imperfect lepidodendroid stems1 the use of the term may be conveniently retained for descriptive purposes4 ,the specimen from the ,commentry coal-field of ,france1 shown in fig4 #aef1 affords some excuse for the institution of several generic names for different states of preservation or decortication of one species4 ,the cortical level exposed at e is characterised by spirally disposed peg-like ridges with truncated apices3 it is this form of cast which is usually designated ,knorria4 ,the ridges vary in size and shape in different types of stem2 they may be narrow as shown at e1 fig4 #aef1 or short and broad with rounded distal ends4 ,in some cases they are forked at the apex1 as in the partially decorticated specimen of ,lepidodendron ,veltheimianum represented in fig4 #ahe1 ,a4 ,illustration3 ,,fig4 #aef4 ,a dichotomously branched ,lepidodendroid stem 7,knorria mirabilis ,ren4 and ,zeill474 7,after ,renault and ,zeiller47 7 nat4 size47 ,the original specimen is in the ,natural ,history ,museum1 ,paris4 a-g1 surface features exposed as the result of different degrees of decortication4 7,see vol4 ,i4 p4 #ajb1 fig4 #bc74 ,the ,knorria state represents the impression or cast of the outer cortical region too deep below the leaf-cushion region to retain any indications of the cushion-form2 the ridges are the casts of the spaces produced in the cortex by the decay of the sheath of delicate cells surrounding each leaf-trace and by the decay of the thin-walled cells of the parichnos4 ,the occasional forked apex of a ridge is the expression of the fact that the cast was made at the region where the parichnos divides into two arms 7cf4 p4 #ajj74 ,in certain specimens it is possible to connect the ,knorria casts with associated lepidodendroid stems which may be determined specifically2 but when we have no evidence as to surface-features the fossils may be designated casts of lepidodendroid stems in the ,knorria condition4 ,such casts are illustrated by numerous drawings in palaeobotanical literature#bgg4 b4 ,bergeria4 ,this is another name first used by ,sternberg in his classic work1 ,die ,flora der ,vorwelt1 for casts of lepidodendroid plants such as ,steinhauer#bgh had previously figured as ,phytolithus cancellatus4 ,brongniart#bgi recognised that the application of the generic title ,lepidodendron should be extended to include specimens referred by ,sternberg to ,bergeria1 and a few years later ,goldenberg#bhj realised that this name does not stand for well-defined generic characters4 ,the correctness of these views was1 however1 first satisfactorily demonstrated by ,carruthers#bha and by ,feistmantel#bhb4 ,if a ,lepidodendron stem loses its superficial layers of outer cortex and in this condition is embedded in sand or mud1 the cast is distinguished from that of a perfect stem by the absence of the leaf-scars and by other features4 ,it may1 however1 still show spirally disposed areas1 corresponding approximately to the original leaf-cushions1 which are characterised by a small depression or pit either at the apex or near the centre of each oval area3 the pit marks the position of the leaf-trace and its parichnos strand4 ,in some cases the exposed surface may be smooth without any indication of leaf-cushions1 while narrow spirally arranged grooves represent the obliquely ascending vascular bundles passing through the cortex to the leaves4 ,fig4 #ahe1 ,b1 shows the ,bergeria state of ,lepidodendron ,veltheimianum1 which differs from the ,knorria condition in the fact that decortication had not extended below the level at which the form of the leaf-cushions could be recognised4 ,it is clear that no sharp line can be drawn in all cases between the different degrees of decortication as expressed by the terms ,knorria and ,bergeria4 ,a list of synonyms of ,knorria1 ,bergeria1 and ,aspidiaria forms of stem and a detailed treatment of their characteristic features may be found in a recent work by ,potoni#bhc4 c4 ,aspidiaria4 ,in one of the earliest ,english books on fossil plants1 the ,antediluvian ,phytology by ,artis#bhd1 a specimen from the ,carboniferous sandstone of ,yorkshire is figured as ,aphyllum cristatum1 and a similar fossil is described as ,a4 asperum4 ,these are impressions of ,lepidodendron stems in which the characteristic leaf-cushions are replaced by smooth and slightly convex areas with a narrow central ridge4 ,to this type of specimen ,presl gave the name ,aspidiaria#bhe1 under the impression1 shared by subsequent writers1 that the supposed external features were entitled to generic recognition4 ,it is to ,stur#bhf that we owe the first satisfactory interpretation of fossils included under the name ,aspidiaria3 he showed that on the removal of the projecting convex areas from some of his specimens a typical ,lepidodendron leaf-cushion was exposed 7fig4 #add1 ,a1 a74 ,the ,aspidiaria condition 7fig4 #add1 ,a1 b7 represents the inner face of the detached shell of outer bark of a ,lepidodendron stem1 while in the ,bergeria casts we have a view of the external face of a stem deprived of its superficial tissues4 ,in a ,lepidodendron stem embedded in sediment the more delicate portions of the leaf-cushions would tend to shrink away from the internal and more resistant tissues of the outer cortex1 thus producing spaces between each cushion2 further decay would cause rupture of the leaf-traces and the superficial tissues would thus be separated from the rest of the stem4 ,the tendency of ,lepidodendron stems to split along the line of phellogen in the outer cortex is seen in fig4 #adh1 ,a1 g4 ,the deposition of sediment on the exposed inner face of this cortical shell would result in the production of a specimen of the ,aspidiaria type3 the reticulum enclosing the spirally disposed convex areas is formed by the impression of the firmer tissue between the leaf-cushions4 vi4 ,lepidodendroid axes known as ,ulodendron and ,halonia4 a4 ,ulodendron4 ,this generic name was suggested by ,lindley and ,hutton#bhg for two specimens from the ,english ,coal-measures characterised by leaf-cushions like those of a ,lepidodendron1 but distinguished by the presence of two vertical rows of large and more or less circular cup-shaped scars4 ,these authors1 while recognising the possibility that the fossils might be identical with ,lepidodendron1 regarded them as generically distinct4 ,the generic title ,ulodendron1 though no longer denoting generic rank1 is still applied to certain shoots of lycopodiaceous plants which may belong to the genera ,lepidodendron1 ,bothrodendron1 and according to some authors#bhh1 also to ,sigillaria4 ,the large specimen from the ,belgian coal-measures1 represented in fig4 #baa1 affords a good example of the ,ulodendron form of shoot of the genus ,bothrodendron1 which is described on page #bdi4 ,the specimen shown in fig4 #aeg shows the ,ulodendron shoot of ,lepidodendron ,veltheimianum4 ,casts of large ,ulodendron scars are occasionally met with as separate fossils bearing a resemblance to an oval shell4 ,in ,steinhauer's paper on ,fossil ,reliquiae#bhi a drawing is given of a ,ulodendron stem under the name ,phytolithus parmatus and a similar stem specifically identical with that shown in fig4 #aeg was figured by ,rhode#bij1 one of the earliest writers on fossil plants1 under the comprehensive designation 8,schuppenpflanze40 ,illustration3 ,,fig4 #aeg4 ,lepidodendron ,veltheimianum4 ,ulodendron condition4 7,from a photograph by ,dr ,kidston of a specimen from the ,calciferous ,sandstone series1 ,midlothian2 nat4 size47 ,kidston 7#jb7 ,pl4 ,,lvii4 ,there has been no lack of ingenuity on the part of authors in offering suggestions as to the meaning of these large cup-like depressions1 and there is still difference of opinion as to their significance4 ,lindley and ,hutton#bia described them as the scars of branches or masses of inflorescence4 ,sir ,joseph ,hooker#bib speaks of a specimen of ,ulodendron1 shown to him by ,mr ,dawes1 on which a large organ1 supposed to be a cone1 was inserted in one of the depressions1 but he was unable to arrive at any conclusion as to the real nature of the fossil4 ,while most authors have seen in the scars pressure-areas formed by the pressure of sessile cones against the surface of a growing branch1 others1 as for example ,geinitz#bic1 have described the depressions as branch-scars4 ,carruthers#bid regarded the scars as those of adventitious roots and ,williamson referred to them as the scars of reproductive shoots4 ,the depressions vary considerably in size4 ,the ,belgian example shown in fig4 #baa possesses scars #i cm4 in diameter4 ,a specimen of ,bothrodendron in the ,manchester ,museum from the ,lancashire ,coal-,measures1 to which ,williamson#bie has referred1 bears two rows of scars #aa-ab cm4 in diameter on a stem #aab cm4 in girth and #bcc cm4 long4 ,the scars occur in two alternate series1 on opposite faces of the axis1 the distance between the successive scars in the same row being #bi cm4 ,the surface-features of this large stem are not preserved4 ,before considering the nature and origin of the scars it is important to remember the considerable size to which they may attain2 other points of importance are the occurrence1 either in the centre of each depression or in an excentric position1 of an umbilicus or slightly projecting boss1 in the centre of which is a pit formed by the decay of an outgoing vascular strand4 ,the sloping sides of the scars sometimes bear elevations resembling leaf-cushions like those on the rest of the stem surface4 ,in the specimen shown in fig4 #aeg the lower margin of each cup shows indistinctly the outlines of what appear to be leaf-cushions1 while the rest of the sloping face is characterised by radial ridges1 which may be due to bracts or leaves4 ,it is obvious that in these cups we have the scars of some lateral organ1 but the evidence afforded by specimens of which the depressions contain the remains of such organs is by no means conclusive4 ,a ,ulodendron has been figured by ,d',arcy ,thompson#bif1 in which the lower part of a lateral organ is attached by a narrow base to one of the scars1 but the preservation is not sufficiently good to enable us to decide whether the organ is a cone or a vegetative shoot4 ,kidston#big has described other examples showing portions of organs in connexion with the scars1 but an examination of the specimens in his collection failed to convince me that his interpretation of them as strobili is correct4 ,the phenomenon known as cladoptosis1 as shown on a stem of the ,conifer ,agathis#bih and certain ,dicotyledonous trees such as ,castilloa1 suggests a possible explanation of the ,ulodendron scars4 ,this comparison was made by ,shattock#bii in #ahhh1 but he did not accept the resemblance as a real one4 ,an objection may be urged to the cladoptosis hypothesis that in ,ulodendron the branch1 whether vegetative or reproductive1 was not attached to the whole of the depressed area4 ,on the other hand1 a lateral branch originally attached by a narrow base may have continued to increase in diameter until its base became slightly sunk in the bark of the stem1 thus producing a cup-like depression which1 on the fall of the branch1 would retain traces of the original surface-features of the stem4 ,mr ,watson#cjj of ,manchester recently published a paper on ,ulodendron scars1 in which he adduces fresh and1 as it seems to me1 satisfactory arguments in favour of the branch-scar hypothesis4 ,fig4 #aeh1 from one of ,mr ,watson's blocks1 illustrates the nature of his evidence4 ,he points out that in the obverse half of a large specimen of ,bothrodendron in the ,manchester ,museum1 the umbilicus consists of a cylindrical hole1 #ah mm4 deep and #h mm4 in diameter1 surrounded by a projecting ring of mineral material which doubtless represents some portion of the original plant3 on the reverse half of the specimen the continuation of the ring is seen as a prominent cone fitting into the cup-like depression in the obverse half3 the conical cast shows that numerous small vascular strands were given off from this ring of tissue1 and these strands have the same arrangement and size as the dots which are found on typical ,ulodendron scars4 ,he interprets the ring surrounding the umbilicus as the remains of the primary wood and the small strands as leaf-traces supplying the branch4 ,illustration3 ,,fig4 #aeh4 ,diagrammatic section through the base of a branch to illustrate the ,branch theory of the ,ulodendroid scar4 7,after ,watson47 ,in the diagrammatic section shown in fig4 #aeh the outer cortex of the main stem is represented by oc #a2 this consists of secondary tissue4 ,the corresponding tissue in the branch is seen at oc #b4 ,the stele of the stem is shown at ,tr4 ,st4 and that of the branch at ,br4 ,st42 lt1 lt1 mark the position of the leaf-traces4 ,if we assume the branch to be detached along the line ,,ls1 the depression would show numerous spirally arranged dots representing the points of exit of leaf-traces and the vascular axis would be exposed in the umbilicus4 ,this explanation appears to me to be in harmony with the surface-features of ,ulodendron scars on both ,bothrodendron and ,lepidodendron stems4 ,the occasional occurrence of leaf-cushions on a portion of a ,ulodendron scar is a difficulty on the cladoptosis hypothesis4 ,assuming that true leaf-cushions occur1 their presence may1 as ,watson suggests1 be due to the folding back of a piece of the outer cortex of the branch which has been 8crushed down on to the area of the scar#cja40 ,since this account was written a note has been published by ,m4 ,renier#cjb in which he describes a specimen of ,bothrodendron from ,lige1 one face of which shows a projecting ,ulodendroid scar with an excentric umbilicus4 ,on the other face is a dichotomously branched shoot with surface-features corresponding to those on the scar2 the evidence that the scar represents the base of the branch is described as indisputable4 ,stur#cjc held the view that the depressions on ,ulodendron stems represent the places of attachment of special shoots comparable with the bulbils of ,lycopodium ,selago1 or1 it may be added1 with the short branches occasionally produced on ,cycas stems4 ,if the depressions were formed by the pressure of the bases of cones1 it is clear that the size of the cavity must be an index of the diameter of the cone4 ,the larger ,ulodendron scars exceed in diameter the base of any known lepidodendroid strobilus4 ,another obvious difficulty1 which has not been overlooked by ,kidston who holds that the scars were produced by sessile cones1 is that in ,lepidodendron ,veltheimianum strobili were borne at the tips of slender branches2 the same difficulty is presented by ,bothrodendron 7,fig4 #bac74 ,it is unlikely that two types of strobili were produced on the same plant1 particularly as the cone of ,l4 ,veltheimianum was heterosporous4 ,the cones of certain species of ,pinus remain attached to the tree for many years and their bases become embedded in the stem2 this is particularly well shown in the drawing of a cone of ,pinus clausa 7fig4 #aei71 for which ,i am indebted to ,mr ,sudworth1 ,dendrologist in the ,united ,states ,forest ,service4 ,mr ,sudworth has drawn my attention to ,p4 attenuata and ,p4 muricata in illustration of the same phenomenon#cjd4 ,the example shown in fig4 #aei cannot1 however1 be matched by any known specimen of ,ulodendron2 in the case of the depressions on the stem of a ,pine the cone-base fits the circular scar1 but in the fossil stems it is practically certain that this was not the case4 ,illustration3 ,,fig4 #aei4 ,pinus clausa4 nat4 size4 ,there can be little doubt that certain ,palaeozoic ,lycopods shed their branches by a method similar to that employed by the ,kauri ,pine of ,new ,zealand and by some species of ,dicotyledons4 ,the evidence adduced in the case of ,bothrodendron punctatum is a strong argument in favour of extending the same explanation to other ,ulodendron shoots4 ,illustration3 ,,fig4 #afj4 ,a4 ,lepidophloios scoticus ,kidst4 ,from a specimen from the ,calciferous ,sandstone1 ,midlothian1 in ,dr ,kidston's ,collection2 rather less than nat4 size4 ,b4 ,l4 scoticus cone4 ,from a specimen from the ,calciferous ,sandstone of ,midlothian in ,dr ,kidston's ,collection2 slightly reduced4 b4 ,halonia4 ,the branched axis with ,lepidophloios leaf-cushions1 represented in fig4 #afj1 ,a1 illustrates a special form of shoot described by ,lindley and ,hutton#cje under the generic name ,halonia4 ,the original specimens referred to this genus are decorticated axes showing remains of ,lepidodendroid leaf-cushions4 ,the spirally disposed circular scars in the specimen of ,halonia 7,lepidophloios scoticus#cjf7 shown in fig4 #afj constitute the characteristic feature of the genus2 they may have the form1 as in fig4 #afj1 ,a1 of circular discs with a central umbilicus marking the position of a vascular strand1 or1 as in the sandstone cast of ,halonia tortuosa shown in fig4 #afacjg1 they may appear as prominent tubercles4 ,the latter example illustrates the condition characteristic of partially decorticated stems4 ,illustration3 ,,fig4 #afa4 ,halonia tortuosa ,l4 and ,h4 ,from a specimen in ,dr ,kidston's ,collection1 from the ,lower ,coal-measures of ,ayrshire 7,no4 #aefa72 nat4 size4 ,in #ahhc ,williamson#cjh described a specimen1 now in the ,leeds ,museum1 which convinced him that ,halonia is merely a special form of ,lepidodendron concerned with the production of fertile shoots or strobili4 ,feistmantel#cji also recognised that ,halonia regularis is identical in the form of the cushions with the type known as ,lepidophloios laricinus4 ,it is worthy of note that under the name ,halonia1 ,feistmantel#caj figured a piece of decorticated axis characterised by two rows instead of the usual spiral series of large cup-shaped scars4 ,recent researches have1 however1 tended to break down the distinction between ,ulodendron and ,halonia founded respectively on the biseriate and spiral arrangement of the scars or tubercles4 ,the interpretation of ,halonial branches as cone-bearing members of ,lepidodendroid plants has passed into a generally accepted statement of fact1 but1 so far as ,i know1 only one specimen has been figured in which strobili are seen attached to an ,halonia axis4 ,this specimen1 described by ,grand',eury#caa from the coal-field of ,gard1 is hardly sufficiently well-preserved to constitute a demonstration of the correctness of the generally received view1 which1 as is not unusual1 has been repeated by one writer after another without due regard being paid to the nature of the evidence on which the statement is based4 ,it may1 indeed1 be correct to describe ,halonial branches as cone-bearing1 but there are certain considerations which make one pause before unhesitatingly accepting this explanation4 ,the vascular strand which passes from the central cylinder of the shoot to the tubercle or scar is composed of a solid rod of xylem distinguished from the main stele by the absence of a pith4 ,in such petrified peduncles as have been discovered the stele is of the medullated type4 ,the common occurrence of strobili terminating slender branches of lepidodendroid plants1 though not a fatal objection to their attachment to ,halonial shoots1 shows that in many cases the cones were borne at the tip of leafy shoots4 ,it may be that some of the ,halonial scars are in origin like those of the ,ulodendron axes of ,bothrodendron and mark the position of deciduous vegetative branches4 ,the first account of the anatomy of ,halonia we owe to ,dawes#cab2 this was followed by a fuller description by ,binney#cac4 ,the history of our knowledge of this type of branch has been given by ,carruthers#cad1 who expressed the opinion that ,halonia is merely a fertile condition of ,lepidophloios and possibly of other lepidodendroid plants4 ,he was also inclined to regard the ,halonial tubercles as younger stages of the larger scars characteristic of the genus ,ulodendron4 ,williamson's contributions to our knowledge of ,halonia are of primary importance2 he supplied further proof of the ,lepidodendroid nature of these branches and advanced our knowledge of their anatomy4 ,in an early paper#cae he expressed the view that the differences on which ,halonia and ,ulodendron are separated are such as result from a difference in age and are not of generic importance4 ,in the last memoir1 of which he was sole author1 published by the ,royal ,society#caf1 ,williamson brought forward further evidence in support of this well-founded opinion4 ,that the fossils known as ,halonia are branches of a lepidodendroid plant is at least certain1 and it is probable that the lateral branches which they bore were fertile1 though satisfactory proof of this is lacking4 ,we know also that ,halonia branches are characterised by the ,lepidophloios form of leaf-cushion2 there is1 however1 no sufficient reason to assume that such branches were never attached to stems with the cushions of the ,lepidodendron form4 ,the further question1 namely whether ,williamson was correct in his contention as to the absence of any essential distinction between ,ulodendron and ,halonia1 does not admit of an unchallenged answer4 ,in #aijc ,weiss#cag described the anatomy of a specimen of a biseriate ,halonia branch of ,lepidophloios4 ,the form of the leaf-cushions is unfortunately not very well preserved1 but ,weiss figures other specimens with two rows of tubercles on which the leaf-cushions are sufficiently distinct to justify a comparison with those of ,lepidophloios4 ,he believes with ,williamson that it is the presence of tubercles in place of scars which distinguishes ,halonia from ,ulodendron1 and that the arrangement of the tubercles or scars is a matter of little importance4 ,he expresses the opinion justified by the evidence available that the absence or presence of tubercles is merely due to accidents of preservation or1 one may add1 to difference in age4 ,kidston#cah dissents from ,weiss's description of his specimen as a biseriate ,halonia2 he regards it as a ,ulodendron branch of ,sigillaria discophora 7,knig74 ,until specimens with more clearly preserved external features are forthcoming it is impossible to settle the point in dispute1 but on the facts before us there would seem to be a prima facie case in favour of ,weiss's contention4 ,the designation ,halonia may be retained as a descriptive term for ,lepidodendroid shoots characterised by spirally disposed scars or tubercles and bearing leaf-cushions of the ,lepidophloios type4 ,in the case of specimens showing prominent tubercles1 the superficial tissues are usually absent and1 as in the fossil represented in fig4 #afa1 the name ,halonia does not necessarily imply the presence of leaf-cushions of a particular type4 vii4 ,anatomical characters of ,vegetative ,lepidodendron shoots 7,lepidodendron and ,lepidophloios74 ,the type already described under the name ,lepidodendron vasculare differs from those dealt with in the following pages chiefly in the anatomy of the stele4 ,the simplest and probably most primitive type of ,lepidodendron stem is that in which the xylem forms a solid rod2 the type of stele most frequently represented is that of ,l4 ,harcourtii1 ,l4 fuliginosum1 and other species in which the diameter of the stele is greater and a cylinder of primary xylem encloses a comparatively large parenchymatous pith4 #a4 ,lepidodendron esnostense1 ,renault#cai4 ,this species was founded by ,renault on petrified specimens from the ,culm beds of ,esnost in ,france4 ,the surface of a young twig bears prominent leaf-cushions of elongated rhomboidal form similar to those of ,lepidodendron obovatum 7fig4 #agc7 and other species4 ,in older branches the primary cortex is replaced by a considerable thickness of radially disposed secondary cortical tissue which1 as shown in tangential section1 consists of a reticulum of elongated pointed elements with comparatively thick walls enclosing meshes filled with large-celled parenchyma4 ,it is worthy of note that if such a branch were exposed to decay1 the earlier destruction of the more delicate tissue in the meshes of the secondary cortex would produce a series of oval depressions1 corresponding to the parenchymatous areas1 separated by a projecting reticulum of the more resistant elements3 a cast of this partially decayed surface would be indistinguishable from that of some types of ,sigillaria or of a ,lyginodendron4 ,the inner regions of the cortex of the type-specimens have not been preserved4 ,the xylem1 which is the only part of the stele represented1 has the form of a protostele or solid cylinder of scalariform tracheids with peripheral groups of narrower protoxylem elements which mark the points of exit of the leaf-traces3 in a branch #a-b cm4 wide the xylem column has a diameter of #c mm4 ,the small leaves 7fig4 #adc1 ,b1 ,c71 similar to those of a ,sigillaria1 are sub-rhomboidal in section near the base and approximately circular near the apex#cbj4 ,the mesophyll consists of palisade cells having the appearance of typical chlorophyll-tissue4 ,the heterosporous strobili attributed to this species bore microsporangia on the upper and megasporangia on the lower sporophylls2 the megaspores1 of which a considerable number occur in each megasporangium1 are identical in size with those of another ,culm form1 ,lepidodendron rhodumnense4 ,some of these have retained traces of prothallus tissue1 and in one spore ,renault figures what he regards as an archegonium3 the drawing is by no means convincing4 #b4 ,lepidodendron rhodumnense1 ,renault#cba4 ,the species from the ,culm of ,combres 7,loire7 agrees in its solid xylem cylinder and in the differentiation of the secondary cortex1 as also in the association of two kinds of spore1 with ,lepidodendron esnostense4 ,a comparison of the leaves of the two types reveals certain differences which may be of specific rank1 but1 apart from minor differences1 these ,culm species may be classed under one anatomical type4 #c4 ,lepidodendron saalfeldense1 ,solms-,laubach#cbb4 ,this ,devonian species was founded on a specimen #c #be cm4 broad at the base1 which shows the stumps of four branches recalling the dichotomously branched arms of ,stigmaria and ,pleuromeia4 ,if these are in reality the remains of ,stigmaria-like horizontal branches the species affords an interesting example of a ,lepidodendron axis with a subterranean rhizome of the type which has been found in several ,sigillarian stems4 ,in the upper end of the axis the stele consists of a solid strand of xylem which is not sufficiently well preserved to show the position of the protoxylem groups4 ,a transverse section taken near the base reveals a type of stele differing from that at the upper end in being composed of radially disposed tracheids and in its resemblance to the stele of ,stigmaria4 #d4 ,lepidodendron fuliginosum1 ,williamson4 ,figs4 #afb-agb1 #agi1 ,e4 #ahga4 ,lepidodendron ,harcourtii1 ,binney1 ,palont4 ,soc41 p4 #dh1 ,pl4 ,,vii4 fig4 #f4 #ahgb4 ,halonia regularis1 ,binney1 ,palont4 ,soc41 p4 #hi1 ,pl4 ,,xv4 #ahha4 ,lepidodendron ,harcourtii1 ,williamson1 ,phil4 ,trans4 ,roy4 ,soc41 ,vol4 #agb1 p4 #bhh1 ,pls4 ,,xlix-,,lii4 #ahhg4 ,lepidodendron fuliginosum1 ,williamson1 ,proc4 ,roy4 ,soc41 ,vol4 ,,xlii4 p4 #f4 #ahia4 ,lepidodendron ,williamsoni1 ,solms-,laubach1 ,fossil ,botany1 p4 #bbf4 #ahic4 ,lepidophloios fuliginosus1 ,kidston1 ,trans4 ,roy4 ,soc4 ,edinburgh1 ,vol4 ,,xxxviii4 p4 #edh4 ,the name ,lepidodendron fuliginosum was proposed by ,williamson in #ahhg for petrified stems previously included by him in ,witham's species ,l4 ,harcourtii1 but subsequently recognised as a distinct type characterised by 8the greater uniformity in the composition of the entire cortex0 and by other features some of which do not constitute distinctive characters4 ,the species agrees with ,l4 ,harcourtii and with ,l4 ,veltheimianum in having a medullated stele2 it is distinguished not only by the more frequent preservation of the middle cortex1 a fact due to a difference in minute structure1 but chiefly by the peculiar structure of the secondary tissue added to the stele2 this is in part composed of radial series of parenchymatous cells and of a varying amount of tracheal tissue the elements of which are narrower than in other species and are characterised also by their sinuous vertical course4 ,as is pointed out in the sequel1 the anatomical features of ,l4 fuliginosum1 as at present understood1 are not confined to one type of ,lepidodendron stem4 ,specimens have been described with leaf-cushions of the form characteristic of ,l4 aculeatum1 ,l4 obovatum and ,lepidophloios combined with the anatomical features of ,williamson's species3 it is possible that the two species ,l4 obovatum and ,l4 aculeatum are not really distinct#cbc1 but it is certain that shoots with both the ,lepidodendron and ,lepidophloios cushions may have the same type of anatomical structure4 ,a more detailed knowledge of the structural features of ,lepidodendron shoots may enable us to define anatomical species with more exactness than is possible at present4 ,there can1 however1 be little doubt that well-marked anatomical features may be associated with more than one specific form of shoot as defined by the form of the leaf-cushions4 ,solms-,laubach proposed the name ,lepidodendron ,williamsoni for the anatomical type ,l4 fuliginosum of ,williamson1 but the latter name has been generally adopted4 ,in the following account special attention is directed to the nature and origin of the secondary stelar tissue and to the secretory zone1 as difference of opinion exists as to the interpretation of these features4 ,among the best examples of shoots of ,lepidodendron fuliginosum without secondary tissue or in which it is feebly developed are those originally described by ,binney4 ,the stele includes a large parenchymatous pith1 the cells of which frequently show signs of recent division1 a feature observed also in the pith of the large stem of ,l4 ,wnschianum1 represented in figs4 #aha1 #ahb4 ,the primary xylem cylinder has an irregularly crenulate outer edge like that of ,l4 ,wnschianum and ,l4 ,harcourtii and the protoxylem elements occupy an exarch position4 ,isodiametric reticulately-pitted elements are met with both on the inner and outer edge of the xylem4 ,illustration3 ,,fig4 #afb4 ,lepidodendron fuliginosum4 ,part of the stele in transverse section4 7,binney ,collection1 ,sedgwick ,museum1 ,cambridge47 ,illustration3 ,,fig4 #afc4 ,lepidodendron fuliginosum4 ,longitudinal section4 7,binney ,collection1 ,cambridge47 ,figs4 #afb and #afc illustrate the structure of the outer portion of the xylem and adjacent tissues in a section of a shoot #ch cm4 #be cm4 in diameter1 which is in the act of branching1 as shown by the occurrence of two steles of equal size4 ,a figure of the complete section will be found in ,binney's memoir#cbd1 and additional illustrations were published in #ahiicbe4 ,illustration3 ,,fig4 #afd4 ,lepidodendron fuliginosum4 ,leaf-trace4 7,binney ,collection1 ,cambridge47 ,the primary xylem 7figs4 #afb1 #afc1 x7 is succeeded by #b-c rows of polygonal cells with dark contents and associated with isodiametric tracheae3 these pass into clearer parenchymatous tissue1 a1 characterised by the arrangement of the cells in vertical series1 to which the term meristematic zone has been applied4 ,the secretory zone1 s1 abutting on the meristematic zone1 consists of more or less disorganised parenchymatous cells and broader and more elongated spaces2 it is interrupted here and there by an outgoing leaf-trace1 as at lt #a and lt #b in fig4 #afb4 ,the secretory zone is succeeded by a homogeneous inner cortex like that described in ,l4 vasculare2 part of this region is seen at the upper edge of fig4 #afb4 ,the broad middle cortex1 which is separated from the inner cortex by a sharply defined boundary1 is composed of rather small lacunar parenchymatous tissue consisting of sinuous tubular elements interspersed among isodiametric cells of various sizes 7fig4 #aff1 p74 ,in the middle cortical region the leaf-traces pursue an almost horizontal course2 one is shown in fig4 #afd1 in oblique longitudinal section1 in a reversed position2 the xylem1 x1 should be on the inner side of the secretory tissue1 s4 ,the clear space between the two parts of the vascular bundle was originally occupied by a few layers of parenchymatous cells1 as seen in the transverse sections1 figs4 #afe and #aff4 ,in some specimens the leaf-traces pass through the middle cortex in a much more vertical course1 as shown by the section represented in fig4 #afe4 ,this section illustrates the structure of a typical leaf-trace with unusual clearness2 it shows the tangentially elongated group of xylem1 the strand of tissue which occupies the position of phloem1 s 7to which the term secretory zone is applied71 the compact parenchyma between the two parts of the bundle1 and surrounding the whole a narrow sheath sharply contrasted by the smaller and more uniform size of the cells from the middle cortex1 a few cells of which are seen in the photograph4 ,the middle cortex shows a well-defined junction with the more compact outer cortical region1 which consists of primary parenchyma passing externally into a zone of phelloderm composed of thick-walled and more elongated cells4 ,a noticeable feature in many ,lepidodendron shoots is the occurrence of a circle of strands of secretory cells often surrounding fairly large ducts just internal to the edge of phelloderm3 similar strands form irregularly concentric circles1 as was pointed out in the case of ,l4 vasculare1 in the phelloderm itself4 ,illustration3 ,,fig4 #afe4 ,lepidodendron fuliginosum4 ,leaf-trace3 x1 xylem2 s1 secretory zone4 7,binney ,collection1 ,cambridge47 ,illustration3 ,,fig4 #aff4 ,lepidodendron fuliginosum4 ,leaf-trace3 p1 parichnos4 7,binney ,collection1 ,cambridge47 ,fig4 #aff shows a leaf-trace in the outer cortex accompanied by its crescent-shaped parichnos1 p1 derived from the middle cortex and by means of which the outer cortex and the lamina of the leaves are connected with the inner region of the shoot4 ,this lacunar middle cortex and parichnos doubtless constitute an aerating tissue-system which after leaf-fall is exposed directly to the air at the ends of the parichnos arms on the leaf-scars4 ,some of the sections in the ,binney ,collection 7,sedgwick ,museum1 ,cambridge7 show early stages in the production of secondary xylem3 in the section represented in fig4 #afg the secretory zone is succeeded on its inner face by a zone of radially elongated cells1 m1 which are clearly in a meristematic condition4 ,the same section shows also the more radially extended form of the xylem of a leaf-trace with its internal protoxylem1 px1 in contrast to the tangentially elongated form which is assumed during its passage through the cortex 7cf4 figs4 #afe1 #aff74 ,illustration3 ,,fig4 #afg4 ,lepidodendron fuliginosum4 7,binney ,collection1 ,cambridge47 ,some sections of ,lepidodendron fuliginosum in the ,manchester ,university ,collection are of special interest from the point of view of the method of secondary thickening4 ,in the section reproduced in fig4 #afh1 ,b1 the meristematic zone is seen to consist in part of radially elongated elements1 m1 with parallel cross-walls evidently of recent origin4 ,the same tissue is shown also in fig4 #afh1 ,c1 a1 ,d1 a1 and in fig4 #afi1 ,a1 a ,this band of meristem1 which we may speak of as the cambium1 occurs in the outer region of the meristematic zone immediately internal to the secretory zone1 sc4 ,illustration3 ,,fig4 #afh4 ,a4 ,lepidodendron vasculare4 7,botany ,school1 ,cambridge47 ,b4 ,lepidodendron fuliginosum4 7,from a specimen from ,shore1 ,lancashire1 in the ,cambridge ,botany ,school ,collection74 ,c4 ,l4 fuliginosum4 78,biseriate ,halonia0 of ,weiss ,no4 #beg1 ,manchester ,university ,museum47 ,d4 ,l4 fuliginosum4 7,manchester ,univ4 ,museum47 ,the result of the activity of this cambium band is the production of secondary parenchyma and tracheal tissue4 ,in fig4 #agi1 ,e1 drawn from a portion of the section represented in fig4 #afh1 ,b1 a projecting arm of primary xylem is seen at x2 this is followed by #b-c layers of parenchymatous cells1 some of which have dark contents1 and beyond this is seen a group of secondary elements1 tr1 cut across somewhat obliquely1 which are evidently products of the cambial cells on the inner margin of the secretory zone1 sc4 ,the longitudinal section 7fig4 #afi1 ,d7 shows the cambial cells1 a1 next the secretory zone1 sc1 passing internally into crushed and imperfectly preserved elongated elements which are presumably miniature tracheae1 and these are succeeded by older and more completely lignified xylem elements1 x4 ,in larger shoots the amount of secondary tissue is considerably greater2 it may consist almost entirely of short-celled parenchyma 7fig4 #afh1 ,c1 from x to sc71 or it may include a large proportion of radially disposed and vertically elongated tracheae 7fig4 #afh1 ,d1 x1 and fig4 #agj1 ,a1 x71 or it may consist of parenchyma containing scattered groups of tracheae 7fig4 #afi1 ,a1 x7#cbf4 ,illustration3 ,,fig4 #afi4 ,lepidodendron fuliginosum4 ,a1 ,b4 7,manchester ,university ,collection4 ,no4 ,q4 #fde ,a47 ,b1 ,c4 7,manchester4 ,no4 #beg47 ,d4 7,manchester4 ,no4 #f47 ,fig4 #afi1 ,a1 is a diagrammatic sketch of the tissues--#a mm4 wide--between the primary xylem1 x1 and the inner cortex4 ,the primary xylem is succeeded by short parenchymatous cells followed by a zone of radially elongated elements passing occasionally into rows of narrow scalariform tracheae1 some of which1 owing to their sinuous longitudinal course 7fig4 #aga1 ,c71 are seen in oblique section1 as at ,c1 fig4 #afi1 ,a4 ,at its outer edge this secondary tissue1 x1 consisting of parenchyma and tracheae1 passes into the cambial band 7fig4 #afi1 ,b1 a74 ,illustration3 ,,fig4 #agj4 ,lepidodendron fuliginosum4 7,from sections in the ,manchester ,museum47 ,the radial longitudinal section represented in fig4 #afh1 ,c1 is taken from the fossil described by ,weiss as a biseriate ,halonia2 it agrees sufficiently closely in structure with others referred to ,lepidodendron fuliginosum to be classed as an example of this anatomical type4 ,a complete transverse section of the stem measures #i #fc cm42 the breadth of the tissues between the edge of the primary xylem and the outer edge of the secretory zone is #be mm4 ,the middle cortical region1 characterised by the sooty appearance1 which led ,williamson to choose the specific name fuliginosum1 is traversed by the leaf-traces and is sharply differentiated from both the inner and outer cortex4 ,the longitudinal section 7fig4 #afh1 ,c7 shows the outer edge of the primary xylem1 x1 abutting on a band of dark and small-celled parenchyma which passes into the broad zone of secondary tissue1 m1 the inner region of which consists of fairly thick-walled elements in radial series passing externally into the thin-walled cells of the cambial region1 a1 on the inner edge of the secretory zone1 sc4 ,this section shows also the interruption of the secretory zone by an outgoing leaf-trace1 lt1 the lower part of which1 sc1 is continued downwards into the secretory zone4 ,the exit of a leaf-trace produces a gap in the secretory zone of the stem1 but not in the xylem4 ,if we applied the term phloem to the secretory zone--a course adopted by ,prof4 ,f4 ,e4 ,weiss and some other authors1 but which ,i do not propose to follow--we should speak of a phloem foliar-gap as a characteristic feature of a ,lepidodendron shoot4 ,this applies to other species of the genus as well as to ,l4 fuliginosum4 ,illustration3 ,,fig4 #aga4 ,lepidodendron fuliginosum4 7,from sections in the ,manchester ,museum47 ,fig4 #aga1 ,a1 shows more clearly the broad zone of secondary parenchyma with the thinner-walled cambial region1 a2 the latter is represented on a larger scale in fig4 #aga1 ,b4 ,the section shown in fig4 #afh1 ,d1 and in fig4 #agj1 ,a1 affords an example of a stem in which the secondary tissue consists largely of narrow scalariform tracheae1 x2 the primary stele has a diameter of #a cm42 the secondary xylem1 x1 forms a fairly broad zone of parenchyma and tracheal elements through which leaf-traces pass vertically1 a fact of some interest in comparison with the horizontal course which they pursue through the medullary rays in the normal secondary wood of ,l4 vasculare and ,l4 ,wnschianum4 ,the secondary tracheae pass gradually into thin-walled cambial cells 7a1 fig4 #afh1 ,d2 #agj1 ,a7 with parallel tangential walls4 ,fig4 #aga1 ,c1 shows the sinuous course of the secondary tracheae as seen in longitudinal section1 and a few small groups of parenchymatous cells1 mr1 which may be of the nature of medullary rays1 enclosed between the winding scalariform tracheae4 ,illustration3 ,,fig4 #agb4 ,lepidodendron fuliginosum4 ,from a section 7#d #cd cm47 in the ,williamson ,collection1 ,british ,museum 7,no4 #cgi71 figured by ,williamson1 ,phil4 ,trans4 ,r4 ,soc4 #ahha1 ,pl4 #eb4 ,the secretory zone of ,lepidodendron fuliginosum agrees essentially with that of other species2 it usually presents the appearance shown in fig4 #afh1 ,b1 sc2 fig4 #afi1 ,b and ,c2 fig4 #agj1 ,b 7longitudinal section72 fig4 #aga1 ,d1 sc4 ,the comparatively large clear spaces which characterise this tissue1 as seen in fig4 #afh1 ,b1 appear to owe their origin to groups of small cells which gradually break down and give rise to spaces containing remnants of the disorganised elements1 as in fig4 #aga1 ,d1 and fig4 #afi1 ,b1 b4 ,the secretory tissue seen in fig4 #agj1 ,b1 consists of large and small parenchymatous cells without any of the broad sacs or spaces such as are shown in fig4 #afi1 ,c4 ,fig4 #agb represents a diagrammatic sketch of a transverse section 7#d #cd cm4 in diameter7 of a young shoot from the ,lower ,coal-,measures of ,lancashire figured by ,williamson#cbg in #ahha as ,lepidodendron ,harcourtii4 ,it shows the features characteristic of ,l4 fuliginosum and is of importance as affording an example of a shoot giving off a branch from the stele to supply a lateral axis of the type characteristic of ,halonia4 ,the exit of the branch-stele forms a gap in the main stele2 a ramular gap as distinguished from a foliar gap4 ,the outgoing vascular strand is at first crescentic1 but becomes gradually converted into a solid stele4 ,the primary xylem of the main stele 7black in the figure7 consists of a ring six tracheae in breadth2 this is succeeded by a few layers of dark parenchymatous cells and a band of radially elongated elements1 a1 which abuts on the secretory zone4 ,the middle lacunar cortex1 c1 with ,stigmaria rootlets1 s1 is fairly well preserved4 ,in the outer cortex occur several leaf-traces1 lt1 accompanied by spaces originally occupied by the parichnos strand1 p4 ,a band of secondary cortex1 consisting chiefly of phelloderm1 is seen at pd4 ,the prominent leaf-cushions1 some of which show the parichnos1 p1 appear to be of the ,lepidophloios type4 ,it remains to consider the external characters of ,lepidodendroid shoots possessing the anatomical features represented by the comprehensive species ,lepidodendron fuliginosum4 ,certain sections exhibiting this type of structure were described by ,binney in #ahgb as ,halonia regularis#cbh on evidence supplied by ,mr ,dawes1 who stated that they were cut from a specimen bearing ,halonia tubercles4 ,the section represented in fig4 #agb is no doubt from an ,halonia axis4 ,in #ahij ,cash and ,lomax#cbi stated that they had in their possession a stem of the ,l4 fuliginosum type with the external features of ,lepidophloios2 this identification has been confirmed by ,kidston#ccj and ,weiss#cca4 ,it is1 however1 equally clear that certain species with the elongated leaf-cushions of ,lepidodendron must be included among examples of shoots with the anatomical characters of ,l4 fuliginosum4 ,illustration3 ,,fig4 #agc4 ,lepidodendron obovatum4 7,from a specimen lent by ,dr ,d4 ,h4 ,scott47 ,dr ,scott#ccb published in #aijf a short account of the structure of a specimen from the ,lower ,coal-,measures of ,lancashire1 the external features of which were identified by ,kidston with those of ,lepidodendron obovatum ,sternb4 ,dr ,scott generously allowed me to have drawings made from his specimen2 these are reproduced in fig4 #agc4 ,the form of the leaf-cushion is by no means perfect2 there is a well-marked median ridge1 and the small circular scar near the upper end of some of the cushions may represent the ligular cavity4 ,at the base of the leaf-cushions a cortical meristem has produced a zone of secondary cortex2 at c a second meristem is seen in the outer cortex3 the dark dots in the cortex mark the positions of leaf-trace bundles4 ,the inner cortex1 d1 is a more compact tissue surrounding the imperfectly preserved secretory zone4 ,from the medullated stele a lateral branch1 b1 is being given off2 its crescentic form becoming changed to circular as it passes nearer to the surface4 ,illustration3 ,,fig4 #agd4 ,lepidodendron aculeatum4 7,cambridge ,botany ,school47 ,illustration3 ,,fig4 #age4 ,lepidodendron aculeatum4 7,cambridge ,botany ,school47 ,a type of ,lepidodendron1 ,l4 ,hickii1 founded on anatomical characters by ,mr ,watson#ccc1 is believed by him to possess leaf-cushions like those of ,l4 obovatum2 if this is so1 it is interesting1 as he points out1 to find two distinct anatomical types associated with one species4 ,watson thinks it probable that the 8species0 ,l4 obovatum includes at least two widely different species4 ,this merely emphasizes the importance of correlating structure and external characters as far as available data permit4 ,illustration3 ,,fig4 #agf4 ,lepidodendron aculeatum4 7,cambridge ,botany ,school47 ,the specimen1 of which part of the surface is shown in fig4 #agd1 is in all probability ,l4 aculeatum ,sternb4 ,this was described by me in detail in ,the ,annals of ,botany 7#aijf7 as another example of the co-existence of the ,lepidodendron fuliginosum type of anatomy with a true ,lepidodendron4 ,the locality of the specimen is not known4 ,the leaf-cushions are #ae cm4 long with tapered upper and lower ends2 a ligular cavity may be recognised on some parts of the fossil1 also faint indications of leaf-trace scars4 ,the tubercles 7fig4 #agd1 ,a-,c1 t7 probably represent leaf-traces which the shrinkage of the superficial tissues has rendered visible in the lower part of their course4 ,the circular scar1 s 7fig4 ,b71 on the partially decorticated surface is apparently a wound4 ,the stele is sufficiently well preserved to justify its reference to ,l4 fuliginosum4 ,the irregularly crenulated edge of the primary xylem1 x 7fig4 #age71 is succeeded by a broad band of parenchyma 7the meristematic zone71 m1 and beyond this are remnants of the secretory zone1 s4 ,the structure of the leaf-traces corresponds with that of other specimens of the type1 but the much steeper course of these vascular strands1 lt1 lt 7fig4 #agf71 is a feature in which this example differs from most of those referred to ,l4 fuliginosum4 ,such evidence as is available would seem to point to the absence of trustworthy criteria enabling us to separate1 on anatomical grounds1 ,lepidophloios and ,lepidodendron#ccd4 ,illustration3 ,,fig4 #agg4 ,stigmaria radiculosa 7,hick74 7,from sections in the ,manchester ,university ,collection47 ,stigmaria radiculosa 7,hick74 ,we have no proof of the nature of the subterranean organs of ,lepidodendron fuliginosum1 though it is not improbable that the specimens described below may be correctly assigned by ,weiss to that species4 ,prof4 ,weiss#cce has made an interesting contribution to our knowledge of a type first described by ,hick#ccf under the name ,tylophora radiculosa1 a designation which he afterwards altered to ,xenophyton radiculosum#ccg and for which we may now substitute ,stigmaria radiculosa 7,hick74 ,prof4 ,williamson expressed the opinion that ,xenophyton exhibited considerable affinity with ,stigmaria ficoides and ,weiss's further study of the species leads him to regard ,hick's plant as probably the ,stigmarian organ of ,lepidodendron fuliginosum4 ,the diagrammatic transverse section represented in fig4 #agg1 ,a 7#de cm4 in diameter71 shows an outer cortex of parenchyma1 c1 consisting in part of radial rows of secondary tissue and of a band of compact parenchyma bounded by the wavy line a2 at sc is a series of secretory strands exactly like those in a corresponding position in ,lepidodendron fuliginosum and other species of the genus4 ,the greater part of the organ is occupied by a lacunar and hyphal middle cortex identical in structure with that shown in fig4 #agh1 ,b1 drawn from a rootlet4 ,at d1 fig4 #agg1 ,a1 the middle cortex has been invaded by a narrow tongue of outer cortical tissue4 ,the stele is characterised by a large pith filled with parenchyma2 in ,stigmaria ficoides#cch the general absence of pith-tissue has led to the inference that the stele was hollow4 ,the xylem is represented by a ring of bundles separated by broad medullary rays2 each bundle contains a few small1 apparently primary1 elements on its inner edge but is mainly composed of radial rows of secondary tracheae x1 fig4 #agg1 ,b4 ,on the outer face of the secondary xylem occur a few smaller and thinner walled cells1 c1 having the appearance of meristematic tissue2 from these additional tracheae were added to the xylem4 ,this meristematic zone occurs1 as in the stems of ,lepidodendron1 immediately internal to the secretory tissue1 sc2 at c1 fig4 #agg1 ,b1 is seen the inner cortical tissue4 ,illustration3 ,,fig4 #agh4 ,rootlet of ,stigmaria4 7,from a section in the ,manchester ,collection47 ,in surface-view a specimen figured by ,hick#cci shows a number of circular scars agreeing in shape and arrangement with the rootlet scars of ,stigmaria ficoides4 ,at b in fig4 #agg1 ,a1 the basal portion of a rootlet is shown in organic connexion with the outer cortex4 ,the rootlet-bundles are given off from the stele as in other examples of ,stigmaria2 each bundle consists of a triangular strand of xylem with an endarch protoxylem at the narrow end accompanied by a portion of the secretory tissue as in the leaf-traces4 ,as in ,stigmaria ficoides the rootlets are attached to the outer cortex above a cushion of small cells4 ,it is interesting to find that rootlet-bundles1 as seen in tangential section of the main axis1 are associated with a parichnos strand1 but this is on the xylem side of the vascular strand1 whereas in the case of leaf-traces the parichnos is on the other side of the bundle4 ,fig4 #agh1 ,a1 represents a transverse section of a rootlet 7#f mm4 in diameter7 associated with ,stigmaria radiculosa and probably belonging to this species4 ,the xylem strand x is composed of a group of tracheae with a single protoxylem strand1 px1 at the pointed end and with small metaxylem elements at the broad end next the space originally occupied by the so-called phloem4 ,a parenchymatous sheath1 c1 surrounds the bundle1 and beyond this is the broad middle cortex1 a small portion of which is shown on a larger scale in fig4 #agh1 ,b2 as ,weiss points out1 some of the outermost cells of the lacunar cortex 7m7 are clearly in a state of meristematic activity4 ,the preservation of the middle cortex and the small quantity of secondary xylem are characters which this ,stigmaria shares with ,lepidodendron fuliginosum1 and although decisive evidence is still to seek1 we may express the opinion that ,weiss's surmise of a connexion between ,stigmaria radiculosa and ,lepidodendron fuliginosum is probably correct4 #e4 ,lepidodendron ,harcourtii4 ,fig4 #agi1 ,a-,d4 ,in #ahca ,mr ,witham#cdj published an anatomical description of a fragment of a ,lepidodendron which he named ,lepidodendron ,harcourtii after ,mr ,c4 ,g4 ,v4 ,vernon ,harcourt from whom the specimen was originally obtained4 ,the fossil was found in rocks belonging to the ,calciferous series in ,northumberland4 ,witham reproduced the account of this species in his classic work on ,fossil ,vegetables#cda1 and ,lindley and ,hutton#cdb1 who examined ,mr ,harcourt's material1 published a description of it in their ,fossil ,flora in which they expressed the view that ,lepidodendron is intermediate between ,conifers and ,lycopods4 ,adolphe ,brongniart#cdc included in his memoir on ,sigillaria elegans an account of ,witham's species based on material presented to the ,paris ,museum by ,mr ,hutton and ,robert ,brown4 ,dr ,kidston#cdd has shown that the actual transverse section figured by ,witham is now in the ,york ,museum2 a piece of stem in the same ,museum1 which is not the specimen from which ,witham's section was cut1 supplied the transverse section figured by ,brongniart4 ,the figures given by ,lindley and ,hutton do not appear to have been made from the ,york specimens4 ,in #ahhg ,williamson#cde published a note in which he pointed out that some of the specimens described by him as ,l4 ,harcourtii should be transferred to a distinct species1 which he named ,l4 fuliginosum4 ,subsequently in #ahic he gave a fuller account of ,witham's species2 it has1 however1 been shown by ,dr ,kidston and by ,mr ,watson#cdf that certain specimens identified by ,williamson as ,l4 ,harcourtii differ sufficiently from that type to be placed in another species1 for which ,watson proposes the name ,l4 ,hickii4 ,a paper on ,l4 ,harcourtii published by ,bertrand#cdg in #ahia extends our knowledge of this type in regard to several anatomical details4 ,it was recognised by ,williamson that the absence of secondary wood in shoots possessing the anatomical characters of ,l4 ,harcourtii is a feature to which no great importance should be attached4 ,it is possible that the large stems from the ,isle of ,arran described by ,williamson#cdh as ,lepidodendron ,wnschianum1 in which the secondary wood is well developed1 may be specifically identical with the smaller specimens from ,northumberland and elsewhere which are recognised as examples of ,witham's type4 ,the diagrammatic sketch shown in fig4 #agi1 ,a1 was made from a section figured by ,williamson in #ahiccdi2 it has a diameter of #i #he cm4 ,the stele is of the medullated type like that of ,l4 ,wnschianum1 and the outer edge of the primary xylem is characterised by sharp and prominent projecting ridges similar to those of ,l4 fuliginosum but rather more prominent4 ,parenchymatous cells succeed the xylem1 as in other species1 but in this case there is no indication of meristematic activity2 beyond this region occur occasional patches of a partially destroyed secretory zone4 ,remains of a lacunar tissue are seen in the middle cortical region2 also numerous leaf-traces1 lt1 consisting of a tangentially elongated xylem strand accompanied by a strand of secretory zone tissue enclosed in a sheath of delicate parenchyma4 ,in the inner part of the outer cortex1 c1 the leaf-traces lie in a space originally occupied by the parichnos2 in the outer portion of the same region a band of secondary cortex1 pd1 has been formed2 immediately internal to this occur numerous patches of secretory tissue1 represented by small dots in the drawing close to pd2 one is shown on a larger scale in fig4 ,b4 ,the position of the phellogen is seen at a2 external to this are radial rows of rather large cells with dark contents4 ,illustration3 ,,fig4 #agi4 ,a-,d4 ,lepidodendron ,harcourtii1 ,witham4 ,e4 ,lepidodendron fuliginosum1 ,shore1 ,lancashire4 ,a1 ,b4 ,from a specimen in the ,williamson ,collection1 ,british ,museum 7,no4 #chj71 from ,airdrie1 ,scotland4 ,c1 ,d4 ,from sections in the ,collection of ,dr ,kidston1 from ,shore1 ,lancashire4 ,fig4 #agi1 ,c1 x1 shows the characteristic form of the primary xylem edge1 beyond which are seen oval or circular leaf-traces with a mesarch protoxylem1 lt1 px4 ,it is possible that this specimen may not be specifically identical with ,witham's species1 but it represents a very similar if not identical type2 it may on the other hand be referable to ,l4 fuliginosum4 ,the importance of the specimen1 apart from its precise specific position1 is that it serves to illustrate the general appearance of the xylem surface met with in both species1 ,l4 ,harcourtii and ,l4 fuliginosum4 ,a tangential longitudinal section1 taken through the line ab in fig4 ,c1 is represented in fig4 #agi1 ,d4 ,the xylem of the leaf-traces lt1 consisting chiefly of scalariform tracheae1 alternates with patches of crushed and delicate parenchyma which immediately abut on the primary xylem2 at p1 p1 the section passes through some of the projecting arms of the xylem cylinder2 at m is seen a patch of meristematic zone tissue4 ,this section together with the similar section of ,lepidodendron vasculare described on a previous page demonstrates that the projecting ridges of the primary xylem form apparently vertical bands3 they are not characterised by a lattice-work arrangement as described by ,bertrand and by other authors who have accepted his conclusions4 ,if a reticulum of intersecting ridges were present on the face of the xylem cylinder its existence would be revealed by such a section as that represented in fig4 #agi1 ,d4 ,illustration3 ,,fig4 #ahj4 ,lepidodendron ,wnschianum4 ,from ,arran4 7 nat4 size47 7,sedgwick ,museum1 ,cambridge47 #f4 ,lepidodendron ,wnschianum 7,williamson74 ,figs4 #ahj-ahd4 ,reference was made in ,volume ,i4 to the occurrence of large stems of a ,lepidodendron in volcanic beds of ,calciferous sandstone age in the island of ,arran#cej4 ,these were discovered and briefly described by ,mr ,wnsch in #ahfgcea and afterwards named by ,carruthers ,lomatophloyos ,wnschianus#ceb4 ,mr ,carruthers visited the locality and published an account of the peculiar method of preservation of the plant remains#cec4 ,it is1 however1 to ,williamson#ced that we owe the more complete description of these ,arran stems4 ,portions of large stems from the ,arran beds are preserved in the ,british ,museum1 the ,sedgwick ,museum1 ,cambridge1 and in the ,manchester ,museum4 ,the section of one of these is shown in fig4 #ahj2 an outer shell of bark encloses a mass of volcanic ash in which are embedded several woody cylinders originally described as 8internal piths#cee10 and by ,carruthers as young stems produced from spores which had germinated in the hollow trunk of a large tree4 ,the true interpretation was supplied by ,williamson who showed that a stem of the dimensions of that represented by the outer cortex1 e1 fig4 #ahj1 must have possessed a single stele of the size of those seen in the interior of the hollow trunk4 ,the additional woody cylinders1 or steles1 were derived from other stems1 and carried1 probably by water1 into the partially decayed trunk4 ,in addition to large ,lepidodendron stems ,williamson described smaller shoots as well as an ,halonial branch and made brief reference to some cones described by ,binney#cef in #ahga from the same locality4 ,the following account of ,lepidodendron ,wnschianum is based on an exceptionally fine specimen discovered by ,mr ,t4 ,kerr of ,edinburgh in ,calciferous sandstone volcanic ashes at ,dalmeny in ,linlithgowshire4 ,the material from this locality described by ,mr ,hill and myself#ceg was generously placed in my hands by ,dr ,kidston of ,stirling4 ,fig4 #aha1 ,a1 shows a transverse section1 #cc cm4 in diameter1 consisting of a shell of outer cortical tissue enclosing a core of light-coloured volcanic ash2 on the decay of the more delicate middle cortex the cylindrical stele dropped to one side of the hollow trunk4 ,the stele1 fig4 #ahb1 has a diameter of #fe cm42 the centre is occupied by concentric layers of silica1 s1 surrounded externally by the remains of a parenchymatous pith1 p1 made up of isodiametric and sinuous hypha-like elements like those in the middle cortex of ,lepidodendron shoots4 ,on the inner edge of the primary xylem1 x1 occur several isodiametric tracheae with fine scalariform and reticulate thickening bands like those in the central region of the stele of ,lepidodendron vasculare3 it is probable that these elements are vestiges of conducting tissue which in ancestral forms formed a solid and not a medullated stele4 ,illustration3 ,,fig4 #aha4 ,lepidodendron ,wnschianum4 ,calciferous ,sandstone1 ,dalmeny4 7,a1 ,sedgwick ,museum1 ,cambridge4 ,b-,f1 ,botany ,school1 ,cambridge47 ,illustration3 ,,fig4 #ahb4 ,lepidodendron ,wnschianum4 ,the stele of the stem shown in fig4 #aha1 ,a4 7,cambridge ,botany ,school47 ,the primary xylem is limited externally by an unequally fluted surface with exarch protoxylem elements2 it is1 however1 noteworthy that there is not always a very clearly defined difference between the small protoxylem and the large centripetally developed tracheae4 ,immediately beyond the primary xylem occur numerous thin-walled parenchymatous cells with spiral and reticulate pitting2 beyond these is the broad zone of secondary xylem1 x1 composed of scalariform tracheae and numerous medullary rays consisting of one1 two1 or several rows of radially elongated elements with spiral and reticulate pitting4 ,in tangential sections the rays are seen to vary considerably in size1 some being made up of a single row of cells while others are longer and broader2 through the latter leaf-traces pass horizontally4 ,portions of medullary rays are seen at mr in fig4 #aha1 ,c and ,e4 ,the leaf-traces given off from projecting ridges on the outer edge of the primary xylem pass upwards for a short distance and then bend outwards through a broad medullary ray2 on reaching the limit of the secondary xylem they again bend sharply upwards1 appearing in transverse section at lt fig4 #aha1 ,b4 ,each leaf-trace consists at first of long tracheae accompanied by numerous thin-walled spiral and reticulate parenchymatous cells derived from the tissue in contact with the outer edge of the primary wood4 ,fig4 #aha1 ,b1 shows a leaf-trace near the edge of the secondary xylem2 it consists of a group of primary tracheae1 with narrower protoxylem elements1 px1 near the outer margin1 almost completely enclosed by radially disposed series of smaller and more delicate tracheae4 ,these secondary elements of the leaf-trace are apparently added during its passage through the medullary ray1 but additions are also made to this tissue by the meristematic zone1 m1 fig4 #aha1 ,b and ,e4 ,in contact with the outermost tracheae of normal size at the edge of the secondary xylem there are some smaller lignified elements1 as at a1 fig4 #aha1 ,e1 and at ,t1 fig4 #ahc2 this juxtaposition of large and small tracheae has been referred to in the description of ,l4 vasculare4 ,prof4 ,williamson#ceh1 in his account of the ,arran specimens of this species1 expressed the opinion that the trees probably perished 8in consequence of the mephitic vapours which filled the atmosphere02 it maybe that in the striking difference in the diameter of the conducting elements on the margin of the wood we have evidence of approaching death4 ,beyond the most recently formed tracheae we have a band of delicate parenchymatous cells 7m1 figs4 ,b and ,e1 #aha2 ,c1 figs4 #ahc1 #ahd7 forming the meristematic zone#cei4 ,the longitudinal section represented in fig4 #ahd shows some recently formed narrow tracheae1 ,t1 and beyond these the meristematic zone composed of thin-walled short cells1 ,c1 arranged in horizontal rows4 ,it is this small-celled tissue to which the name phloem has been applied by some authors#cfj1 a term which seems to me to be misleading and inappropriate4 ,in passing through this zone of dividing cells the leaf-traces become surrounded by an arc of meristem from which elements are added to the radially placed rows of secondary tracheae4 ,beyond the meristematic region portions of the secretory zone are preserved1 consisting of large sacs or spaces and small dark cells as seen in figs4 #aha1 ,b1 ,e1 sc1 ,f2 #ahc1 #ahd4 ,this tissue has the same structure as in ,l4 vasculare and in ,l4 fuliginosum3 it is a striking fact that there are no indications of any additions to the secretory zone even in stems with such a large amount of secondary xylem as in the ,dalmeny specimen 7fig4 #ahb1 x74 ,if the secretory zone were of the nature of phloem we should expect to see signs of additions made to it in the course of growth4 ,in this connexion it is worth mentioning that in the recent fern ,botrychium 7,ophioglossaceae7 secondary xylem is formed in the stem1 but apparently no additions are made to the phloem4 ,the structure of the secretory zone tissue as seen in the longitudinal section fig4 #ahd1 ,s1 is also a serious difficulty in the way of accepting the designation phloem as employed by ,scott and ,weiss4 ,between the secretory zone and the outer cortical region1 no tissues have been preserved4 ,the shell of bark consists chiefly of radial rows of elongated cells with rather thick walls characterised by the occurrence of small intercellular spaces and by tangentially placed bands of secretory cells and sacs 7fig4 #aha1 ,d1 s74 ,immediately internal to the secondary cortex or phelloderm occur groups of secretory tissue as shown in the section of ,l4 ,harcourtii 7fig4 #agi1 ,b74 ,illustration3 ,,fig4 #ahc4 ,lepidodendron ,wnschianum4 ,from the specimen shown in fig4 #aha1 ,s1 secretory zone2 ,c1 meristem2 ,t1 immature tracheae4 ,illustration3 ,,fig4 #ahd4 ,lepidodendron ,wnschianum4 ,longitudinal section of the specimen represented in transverse section in fig4 #ahc4 ,the large tree shown in transverse section in fig4 #aha1 ,a1 has lost its leaf-cushions2 the bark1 as seen in the lower part of the photograph1 presents a fissured appearance like that with which we are familiar on an old ,oak or ,elm stem4 ,a radial longitudinal section through the phelloderm revealed the existence of a crushed leaf-trace passing outwards in an approximately horizontal course accompanied by a strand of parenchymatous tissue#cfa having the characteristic structure of a parichnos4 ,it is probable that the surface of this partially decorticated stem differed in appearance from that of an old ,sigillaria 7cf4 fig4 #aih7 in the much smaller and less conspicuous parichnos strands4 ,in addition to the large stems of ,l4 ,wnschianum from ,arran and ,dalmeny numerous examples of smaller axes from the former locality are represented in the ,williamson collection 7,british ,museum74 ,some of the twigs are characterised by a solid stele 7protostele7 giving off numerous leaf-traces accompanied by short spirally thickened tracheids like those which occur at the outer edge of the primary xylem in the larger stem3 these extend into the leaf where they are arranged round the vascular bundle like the transfusion tracheids#cfb in many recent conifers4 ,the surface of these smaller shoots bears large leaf-cushions which are seen in longitudinal section to have the form characteristic of ,lepidophloios4 ,it is worthy of note that a section of a bifurcating axis of this species from the ,calciferous ,sandstone of ,craigleith 7,british ,museum ,collection#cfc71 although its diameter is #ai #ad cm41 shows no signs of secondary wood4 ,this late appearance of secondary xylem and other anatomical features suggest the possibility of the specific identity of ,l4 ,wnschianum and ,l4 ,harcourtii#cfd4 ,in #ahga ,binney#cfe described a specimen of a heterosporous cone1 ,lepidostrobus ,wnschianus1 from ,arran exhibiting the ordinary features of lepidodendroid strobili2 this was probably borne by ,lepidodendron ,wnschianum4 #g4 ,lepidodendron macrophyllum 7,williamson74 ,fig4 #ahf1 ,c4 ,the diagrammatic sketch reproduced in fig4 #ahf1 ,c1 was made from the transverse section of a small twig1 slightly less than #b cm4 in its longest diameter1 originally figured by ,williamson#cff in #ahgb4 ,earlier in the same year ,carruthers#cfg published a short account of the same form based on specimens collected by ,mr ,butterworth from the ,coal-,measures of ,lancashire near ,oldham1 but both authors refrained from instituting a new specific name4 ,in a later publication ,williamson spoke of the type as ,lepidodendron macrophyllum#cfh4 ,williamson's species has nothing to do with ,lycopodites macrophyllus of ,goldenberg#cfi4 ,the most striking feature of this rare form is the large size of the leaf-cushions1 which are of the ,lepidophloios type1 in proportion to the diameter of the shoot4 ,the stele consists of a ring of xylem1 all of which is primary in the sections so far described1 enclosing a parenchymatous pith3 a ,stigmarian rootlet is shown at s4 #h4 ,lepidodendron ,veltheimianum ,sternb4 7,general account74 ,figs4 #aeg1 #ahe1 #ahf1 ,a1 ,b4 #ahbj4 8,schuppenpflanze10 ,rhode1 ,beit4 zur ,pflanzenkunde der ,vorwelt1 ,pl4 ,,iii4 fig4 #a4 #ahbe4 ,lepidodendron ,veltheimianum1 ,sternberg1 ,flora der ,vorwelt1 ,pl4 ,,lii4 fig4 #e4 #ahcf4 ,pachyphloeus tetragonus1 ,goeppert1 ,die fossilen ,farnkruter1 ,pl4 ,,xliii4 fig4 #e4 #aheb4 ,sagenaria ,veltheimiana1 ,goeppert1 ,foss4 ,flora des bergangsgebirges1 ,pls4 ,,xvii-,,xxiv4 #ahge4 ,lepidodendron ,veltheimianum1 ,stur1 ,culm ,flora1 p4 #bfi1 ,pls4 ,,xviii-,,xxii4 #ahhf4 ,lepidodendron ,veltheimianum1 ,kidston1 ,catalogue of ,palaeozoic plants1 ,british ,museum1 p4 #afj4 #aija4 ,lepidodendron ,veltheimianum1 ,potoni1 ,silur und ,culm ,flora1 p4 #aaf1 figs4 #gb-gf4 #aijd4 ,lepidodendron ,veltheimianum1 ,zalessky1 ,mm4 ,com4 ,gol4 ,russie1 ,pl4 ,,iv4 figs4 #d1 #e4 #aijf4 ,lepidodendron ,veltheimi1 ,potoni1 ,knigl4 ,preuss4 geol4 ,landesanstalt1 ,lief4 ,,iii4 ,the above list may serve to call attention to a few synonyms#cgj of this plant1 and to a selection of sources from which full information may be obtained as to the history of our knowledge of this characteristic and widely spread ,lower ,carboniferous type4 ,lepidodendron ,veltheimianum is represented by casts of stems1 the largest of which hitherto described reaches a length of #ebb metres with a maximum diameter of #fc cm42 this specimen1 figured by ,stur#cga1 consists of a tapered main axis giving off smaller lateral shoots1 some of which exhibit dichotomous branching4 ,fig4 #ahe1 ,c and ,d1 represent the external features of a well-preserved cast and impression respectively4 ,oblique rows of prominent cushions wind round the surface of the stem and branches3 each cushion is prolonged upwards and downwards in the form of a narrow ridge with sloping sides which connects adjacent cushions by an ogee curve4 ,at the upper limit of the broader kite-shaped portion of the cushion the ligular pit forms a conspicuous feature2 immediately below this is the leaf-scar with its three small scars1--the lateral parichnos strands and the central leaf-trace4 ,the two oval areas shown in fig4 #ahe1 ,d1 just below the lower edge of the leaf-scars1 represent the parichnos arms which impinge on the surface of the cushions on their way to the leaves1 as explained on a previous page4 ,it is possible that these areas were visible on the living stem as strands of loose parenchyma comparable with the lenticel-like pits on the stipules of ,angiopteris#cgb and the leaf-bases of ,cyatheaceous ferns1 or it may be that their prominence in the specimen before us is the result of the decay of a thin layer of superficial cortex which hid them on the living tree4 ,fig4 #ahe1 ,b1 illustrates the appearance of a stem in a partially decorticated condition 7,bergeria state74 ,a further degree of decortication is seen in fig4 #ahe1 ,a1 which represents the ,knorria condition4 ,illustration3 ,,fig4 #ahe4 ,lepidodendron ,veltheimianum4 ,from specimens in ,dr ,kidston's ,collection4 7,approximately nat4 size47 ,fig4 #aeg shows a ,ulodendron axis of this species2 in the lower part the specimen illustrates the partial obliteration of the surface features as the result of the splitting of the outer bark consequent on growth in thickness of the tree4 ,by an extension of the cracks1 shown in an early stage in fig4 #aeg1 the leaf-cushions would be entirely destroyed and the surface of the bark would be characterised by longitudinal fissures simulating the vertical grooves and ridges of a ,sigillarian stem4 ,the large stumps of trees shown in the frontispiece to ,volume ,i4 are probably1 as ,kidston#cgc suggests1 trunks of ,l4 ,veltheimianum in which the leaf-cushions have been replaced by irregular longitudinal fissures4 ,in old stems of ,sigillaria the enlarged parichnos areas constitute a characteristic feature 7p4 #bje71 but it does not follow that the absence of large parichnos scars is a distinguishing feature of all ,lepidodendra4 ,in this species1 as in others1 the form of the leaf-cushion exhibits a considerable range of variation dependent on the thickness of the shoot2 the contiguous cushions of young branches become stretched apart as the result of increasing girth of the whole organ1 and casts of still older branches may exhibit very different surface-features#cgd4 ,the leaves as seen on impressions of slender branches are comparatively short1 reaching a length of #a-b cm4 ,it is important to notice that leafy twigs of this species may bear terminal cones#cge resembling in form those of ,picea excelsa and other recent conifers1 though differing essentially in their morphological features4 ,the fossil stumps of trees represented in the frontispiece to ,volume ,i4 bear horizontally spreading and dichotomously branched root-like organs having the characters of ,stigmaria ficoides#cgf4 ,geinitz has suggested that ,stigmaria inaequalis ,gpp4 may be the underground portion of ,lepidodendron ,veltheimianum4 ,it is unfortunately seldom possible to connect petrified ,lepidodendron cones with particular species of the genus based on purely vegetative characters1 but it is practically certain that we are justified in recognising certain strobili described by ,williamson#cgg from the ,calciferous ,sandstone series of ,burntisland on the ,firth of ,forth as those of ,lepidodendron ,veltheimianum4 ,williamson believed that the cone which he described belonged to the plant with shoots characterised by the anatomical features of his species ,lepidodendron brevifolium 7 ,l4 ,veltheimianum71 a conclusion which is confirmed by ,kidston#cgh4 ,the cone of ,l4 ,veltheimianum1 which reached a diameter of at least #a cm4 and a length of #d cm41 agrees in essentials with other species of ,lepidostrobus2 the axis has a single medullated stele of the same general type as that of the vegetative shoots of ,lepidodendron fuliginosum and ,l4 ,harcourtii4 ,the sporophylls are described by ,williamson as spirally disposed1 and ,scott notices that in some specimens they are arranged in alternate whorls2 as in recent ,lycopods both forms of phyllotaxis may occur in the same species4 ,the heterosporous nature of this strobilus1 to which ,scott first applied the name ,lepidostrobus ,veltheimianus1 is clearly demonstrated by the two longitudinal sections contributed by ,mr ,carruthers and figured by ,williamson in #ahiccgi4 ,each sporophyll1 attached almost at right angles to the cone-axis1 bears a radially elongated sporangium seated on the median line of its upper face2 its margins are laterally expanded as a thin lamina2 from the middle of the lower face a narrow keel extends downwards between two sporangia belonging to a lower series4 ,from the base of a sporangium a mass of sterile tissue penetrates into the spore-producing region as in the large sporangia of ,isoetes 7cf4 fig4 #aia1 ,h1 a1 and fig4 #acc1 ,h74 ,the distal and free portion of the sporophylls is bent upwards as a protecting bract4 ,some of the sporangia in the upper part of the cone produced numerous microspores1 while #h-af megaspores occur in the lower sporangia4 ,the megaspores1 having a mean diameter of #jh mm4 8quite #dj times the size of the microspores#chj10 are characterised by tubular capitate appendages1 and by a conspicuous three-lobed projection 7fig4 #aia1 ,e7#cha which1 as ,scott suggests1 may represent the outer spore-wall which has split as the result of germination4 ,it is not improbable1 as shown in fig4 #aia1 ,i1 that this cap was present before germination4 ,the megaspores represented in fig4 #aia1 ,i1 illustrate their characteristic form as seen in a section of a megasporangium1 ,sm2 the open beak-like portion of the larger spore is probably the apical region which has split along the three-rayed lines4 ,these lines form a characteristic feature of both recent and extinct spores and denote their origin in tetrads4 ,the spore shown in fig4 #aia1 ,e#chb1 illustrates the external features4 ,the apical region of the prothallus of a megaspore of ,lepidodendron ,veltheimianum described by ,mr ,gordon#chc consists of smaller cells than those occupying the greater part of the spore-cavity1 a differentiation which he compares with that of the prothallus of ,selaginella4 ,illustration3 ,,fig4 #ahf4 ,a1 ,b4 ,lepidodendron ,veltheimianum4 7,botany ,school1 ,cambridge47 ,c4 ,lepidodendron macrophyllum4 7,british ,museum4 ,no4 #cgg47 x1 ,primary xylem2 x1 secondary xylem2 s1 ,stigmarian rootlet4 ,there can be little doubt that the petrified shoots described by ,williamson#chd from the ,calciferous ,sandstone beds of ,burntisland as ,lepidodendron brevifolium are identical with specimens possessing the external features of ,l4 ,veltheimianum4 ,in #ahgb ,dawson expressed the opinion that ,williamson's species should be referred to ,l4 ,veltheimianum1 and evidence subsequently obtained confirms this view4 ,the stele of this species is of the medullated type1 differing from that of ,l4 fuliginosum and ,l4 ,harcourtii in the absence of prominent ridges on the external surface of the primary xylem1 and from ,l4 vasculare in the possession of a parenchymatous pith4 ,in younger twigs the cortex consists of fairly homogeneous tissue1 but in older branches there is a greater distinction between a delicate middle cortex and a stronger outer cortex4 ,fig4 #ahf1 ,a1 represents a stem in which the vascular cylinder is composed of a primary xylem ring1 x1 #ae mm4 broad1 succeeded by a zone of secondary wood #ab cm4 in breadth4 ,the junction between the primary and secondary xylem is shown on a larger scale in fig4 #ahf1 ,b4 ,the tissues abutting on the secondary xylem have not been preserved2 the outer cortex1 which consists chiefly of secondary elements1 is divided superficially into unequal ridges corresponding to the leaf-cushions which have been more or less obliterated as the result of growth in thickness of the stem4 #i4 ,lepidodendron ,pedroanum 7,carruthers74 ,in #ahfi ,mr ,carruthers described some specimens of vegetative stems and isolated sporangia1 collected by ,mr ,plant in ,brazil1 as ,flemingites ,pedroanus#che4 ,from a more recent account published by ,zeiller#chf it is clear that ,carruthers' species is a true ,lepidodendron2 an examination of the type-specimens in the ,british ,museum confirms this determination4 ,the contiguous leaf-cushions have rounded angles similar in form to those of ,lepidodendron ,veltheimianum and ,l4 dichotomum1 but it is not unlikely that the ,brazilian plant is specifically distinct from ,european species4 ,a figure of one of the specimens on which ,carruthers founded the species is given by ,arber#chg in his ,glossopteris ,flora4 ,the ,brazilian plant is chiefly interesting as affording proof of the existence of ,lepidodendron in the southern hemisphere2 the species has also been recognised in ,south ,africa from material collected by ,mr ,leslie at ,vereeniging#chh4 ,as ,zeiller#chi has suggested1 it is not improbable that the fossils described by ,renault#cij from ,brazil as ,lycopodiopsis ,derbyi may be the petrified stems of ,lepidodendron ,pedroanum4 ,the structure of the central cylinder of ,renault's species is of the type represented by ,l4 ,harcourtii2 the xylem forms a continuous ring and does not consist of separate strands of tracheae as ,renault believed4 #aj4 ,lepidodendron australe 7,m',coy74 ,figs4 #ahg1 ,a-,c4 ,specimens described under this name are interesting rather on account of their extended geographical range and geological antiquity than on botanical grounds4 ,the drawings reproduced in fig4 #ahg illustrate the characteristic appearance of this ,lower ,carboniferous and ,upper ,devonian type1 as represented by a specimen recently described#cia from the ,lower ,karroo 7,dwyka7 series1 which is probably of ,carboniferous age1 near ,orange ,river ,station1 ,south ,africa4 ,the surface is divided into polygonal or rhomboidal areas 7figs4 ,a and ,b7 #h-i mm4 long and #g-h mm4 broad1 arranged in regular series and representing leaf-scars1 comparable with those of ,sigillaria ,brardi and other species1 or possibly partially decorticated leaf-cushions4 ,a short distance below the apex of each area there is a more or less circular prominence or depression 7fig4 #ahg1 ,b7 and on a few of the areas there are indications of a groove 7fig4 ,a1 g7 extending from the raised scar to the pointed base1 as at g1 g4 ,illustration3 ,,fig4 #ahg4 ,lepidodendron australe4 ,fig4 ,a1 nat4 size4 ,in examining the graphitic layer on the surface of the ,south ,african specimen shown in fig4 #ahg1 ,a1 use was made of a method recently described by ,professor ,nathorst#cib4 ,a few drops of collodion were placed on the surface1 and after a short interval the film was removed and mounted on a slide4 ,the addition of a stain facilitated the microscopic examination and the drawing of the collodion film4 ,the cell-outlines 7fig4 #ahg1 ,c7 on the surface of the polygonal areas may be those of the epidermis1 but they were more probably formed by a subepidermal tissue2 the scar1 which interrupts the continuity of the flat surface1 may mark the position of a leaf-base1 or1 assuming a partial decortication to have occurred prior to fossilisation1 it may represent a gap in the cortical tissue caused by the decay of delicate tissue which surrounded the vascular bundle of each leaf in its course through the cortex of the stem4 ,if the impression were that of the actual surface of a ,lepidodendron or a ,sigillaria1 we should expect to find traces of the parichnos appearing on the leaf-scar as two small scars1 one on each side of the leaf-bundle4 ,in specimens from ,vereeniging described in #ahigcic as ,sigillaria ,brardi1 which bear a superficial resemblance to that shown in fig4 ,a1 the parichnos is clearly shown4 ,on the other hand1 an impression of a partially decorticated ,lepidodendroid stem need not necessarily show the parichnos as a distinct feature3 owing to its close association with the leaf-trace in the outer cortex1 before its separation in the form of two diverging arms1 it would not appear as a distinct gap apart from that representing the leaf-bundle4 ,the absence of the parichnos may be regarded as a point in favour of the view that the impression is that of a partially decorticated stem4 ,similarly1 the absence of any demarcation between a leaf-cushion and a true leaf-scar such as characterises the stems of ,lepidodendra and many ,sigillariae is also favourable to the same interpretation4 ,in #ahgb ,mr ,carruthers#cid described some fossils from ,queensland1 some of which appear to be identical with that shown in fig4 #ahg under the name ,lepidodendron nothum1 ,unger#cie1 a species founded on ,upper ,devonian specimens from ,thuringia4 ,the ,queensland plant is probably identical with ,dawson's ,canadian species1 ,leptophloeum rhombicum#cif4 ,in #ahgd ,m',coy#cig instituted the name ,lepidodendron australe for some ,lower ,carboniferous specimens from ,victoria1 ,australia3 these are in all probability identical with the ,queensland fossils referred by ,carruthers to ,unger's species1 but as the identity of the ,german and ,australian plants is very doubtful#cih it is better to adopt ,m',coy's specific designation4 ,krasser#cii has described a similar1 but probably not specifically identical1 type from ,china2 from ,devonian rocks of ,spitzbergen ,nathorst#djj has figured1 under the name ,bergeria1 an example of this form of stem1 and ,szajnocha#dja has described other specimens from ,lower ,carboniferous strata in the ,argentine4 ,lepidodendron australe has been recorded from several ,australian localities#djb from strata below those containing the genus ,glossopteris and other members of the ,glossopteris1 or1 as it has recently been re-christened1 the ,gangamopteris#djc ,flora4 viii4 ,fertile shoots of ,lepidodendron4 ,a4 ,lepidostrobus4 ,the generic name ,lepidostrobus was first used by ,brongniart#djd for the cones of ,lepidodendron1 the type-species of the genus being ,lepidostrobus ornatus1 the designation given by the author of the genus to a ,lepidostrobus previously figured by ,parkinson#dje in his ,organic ,remains of a ,former ,world4 ,the generic name ,flemingites proposed by ,carruthers#djf in #ahfe1 under a misapprehension as to the nature of spores which he identified as sporangia1 was applied to specimens of true ,lepidostrobi4 ,brongniart also instituted the generic name ,lepidophyllum for detached leaves of ,lepidodendron1 both vegetative and fertile2 the specimen figured by him in #ahbb as ,filicites 7,glossopteris7 dubius#djg1 and which was afterwards made the type-species of the genus1 was recognised as being a portion of the lanceolate limb of a large single-veined sporophyll belonging to a species of ,lepidostrobus4 ,in an unusually large ,lepidophyllum1 or detached sporophyll of ,lepidostrobus1 in the ,manchester ,university ,museum1 the free laminar portion reaches a length of #h cm4 ,it is not uncommon to find ,lepidodendron preserved in the form of a shell of outer cortex1 which has become separated along the phellogen from the rest of the stem2 as the result of compression the cylinder of bark may assume the appearance of a flattened stem covered with leaf-cushions4 ,a specimen preserved in this way was described by ,e4 ,weiss as a cone of ,lomatophloios macrolepidotus ,gold41 and is quoted by ,solms-,laubach and other authors#djh as an example of an unusually large ,lepidostrobus4 ,an examination of the type-specimen in the ,bergakademie of ,berlin convinced me that ,weiss had mistaken the partially destroyed leaf-cushions for sporophylls1 and ,stigmarian rootlets1 which had invaded the empty space1 for sporangia#dji4 ,in external appearance some species of ,lepidostrobus bear a superficial resemblance to the cone of a ,spruce ,fir 7,picea excelsa71 but the surface of a lycopodiaceous strobilus is usually covered by the overlapping and upturned laminae which terminate the more or less horizontal sporangium-bearing portion of the sporophyll4 ,fig4 #ahh affords a good example of a long and narrow ,lepidostrobus4 ,this specimen from the ,middle ,coal-,measures of ,lancashire has a length of #bc cm42 like other ,lepidostrobi it is borne at the tip of a slender shoot4 ,the fossil is sufficiently well preserved to show the characteristic radially elongated form of the large sporangia and the long and upturned distal portions of the sporophylls4 ,we may briefly describe ,lepidostrobus as follows3--,cylindrical strobili consisting of an axis containing a single cylindrical stele which agrees generally with that of the vegetative shoots of ,l4 ,harcourtii and other species4 ,the amount of parenchymatous pith varies in different forms2 in some the primary xylem is almost solid4 ,the middle cortical region1 which has usually been destroyed before fossilisation1 possesses the loose lacunar structure characteristic of this region in the vegetative branches4 ,the thicker walled outer cortex is continued at the periphery into crowded1 usually spirally disposed sporophylls1 each of which consists of a more or less horizontal pedicel1 which may be characterised by a keel-like median ridge on its lower surface1 while to the central region of the upper face is attached a large radially elongated sporangium4 ,one of the chief differences between a ,lepidodendron cone and those of the recent genus ,lycopodium is the greater radial elongation of the sporangia in the former4 ,some species of ,lepidostrobus may have been homosporous2 some are known to be heterosporous4 ,in the latter the megasporangia borne on the lower sporophylls usually contain several megaspores as in ,isoetes 7cf4 fig4 #acc1 ,e74 ,beyond the distal end of the sporangium the sporophyll becomes broader in a horizontal plane and is bent upwards as a lanceolate limb2 it may also be prolonged a short distance downwards as a bluntly triangular expansion4 ,illustration3 ,,fig4 #ahh4 ,lepidostrobus4 ,middle ,coal-,measures1 ,bardsley1 ,lancashire4 ,from a specimen in the ,manchester ,museum4 7 nat4 size47 ,there can be little doubt that the ,palaeozoic ,lepidodendra1 like ,lycopodium cernuum 7fig4 #abc7 and other recent ,lycopods1 usually bore their cones at the tips of slender shoots4 ,the fertile shoot of ,lepidophloios scoticus shown in fig4 #afj1 ,b1 affords one of several instances supporting this statement2 similar examples are figured by ,brongniart#daj1 ,morris#daa1 and by more recent writers4 ,the apparently sessile cone figured by ,williamson#dab from a specimen in the ,manchester ,museum is certainly not in situ1 but is accidentally associated with the stem4 ,the general absence of secondary wood in the steles of ,lepidostrobi is1 as ,dr ,kidston#dac points out1 consistent with the view that the cones were shed on maturity and that fertilisation probably took place on the ground1 or perhaps on the surface of the water where the slender hairs of the megaspores 7fig4 #aia1 ,f1 ,i7 may have served to catch the microspores4 ,illustration3 ,,fig4 #ahi4 ,lepidostrobus4 ,section through the apical region of a cone above the axis4 7,manchester ,university ,collection47 ,fig4 #ahi is an accurate representation of a transverse section1 #f mm4 in diameter1 of what is no doubt the apical portion of a ,lepidostrobus from the ,coal-,measures of ,shore1 ,lancashire4 ,the section cuts across the upturned free laminae above the level of the apex of the cone-axis4 ,each lamina contains a small vascular bundle composed of a few tracheae and some thin-walled cells surrounded by delicate mesophyll tissue4 ,immediately in front of the distal end of a sporangium a small ligule is borne on the upper face of the sporophyll 7fig4 #aia1 ,a1 ,b1 l7 occupying the same position as in ,selaginella 7cf4 fig4 #aca1 ,f74 ,strands of vascular tissue pass in a steeply ascending course from the xylem to the pedicels of sporophylls1 finally curving upwards and ending in the upper limb4 ,each vascular bundle consists of a strand of xylem1 apparently of mesarch structure1 accompanied by a few layers of parenchyma on its outer face and by a group of cambiform elements1 the whole being enclosed in a sheath of parenchyma continuous with the inner cortex of the cone axis4 ,the vascular bundle is accompanied by a parichnos in the outer cortex and in the sporophyll4 ,reference has already been made to the belief on the part of some palaeobotanists that the large scars of ,ulodendron represent attachment-surfaces of sessile cones1 and reasons have been given against the acceptance of this view4 ,there is considerable range in the size of ,lepidostrobi4 ,an incomplete specimen1 #cc cm4 long and #f cm4 broad1 which may have been #ej cm4 in length1 is described by ,renault and ,zeiller#dad from the ,commentry ,coal-field4 ,the larger cones afford a striking demonstration of the enormous spore-output of some species of ,lepidodendron4 ,among the earliest accounts of the anatomy of ,lepidostrobus are those by ,hooker#dae and ,binney#daf4 ,one of the specimens described by the former author 7fig4 #aij7 affords an interesting example of an unusual manner of fossilisation2 a hollow stem or ,lepidodendron is filled with sedimentary material containing several pieces of ,lepidostrobi in an approximately vertical position4 ,illustration3 ,,fig4 #aij4 ,lepidodendron stem with ,lepidostrobi4 7,after ,hooker47 ,a4 ,side-view showing leaf-cushions on the left-hand side and the ,knorria condition on the right4 ,b4 ,view of transverse section2 s1 sections of ,lepidostrobi4 ,the fact that ,lepidostrobi usually occur as isolated specimens renders it impossible in most cases to refer them to particular species of ,lepidodendron4 ,neither external features nor anatomical characters afford satisfactory criteria by which to correlate vegetative and fertile shoots2 in some measure this is due to the imperfection of our knowledge as regards the range of structure within the limits of species2 it is also due to lack of information as to the extent to which the transition from sterile to fertile portions of a shoot is accompanied by anatomical differences4 ,prof4 ,williamson wrote3 8,i have for many years endeavoured to discover some specific characters by which different ,lepidostrobi can be distinguished and identified1 but thus far my efforts have been unsuccessful#dag40 ,in a few cases1 such as those mentioned in the description of ,lepidodendron ,veltheimianum and ,l4 ,wnschianum1 it has been possible to correlate cones and vegetative shoots4 ,the most complete account we possess of the anatomy of ,lepidodendron cones is that by ,mr ,maslen#dah1 who first demonstrated the occurrence of a ligule on the sporophylls1 and thus supplied a missing piece of evidence in support of the generally accepted view as to the homology of the sporangium-bearing members and foliage leaves4 i4 ,lepidostrobus variabilis 7,lindley and ,hutton74 #ahaa4 8,strobilus10 ,parkinson1 ,organic ,remains1 ,vol4 ,i4 p4 #dbh1 ,pl4 ,,ix4 fig4 #a4 #ahbh4 ,lepidostrobus ornatus1 ,brongniart1 ,prodrome1 p4 #hg4 #ahca4 ,l4 variabilis1 ,lindley and ,hutton1 ,foss4 ,flora1 ,pls4 ,x4 ,,xi4 #ahca4 ,l4 ornatus1 ,lindley and ,hutton1 ,foss4 ,flora1 ,pl4 ,,xxvi4 #ahcg4 ,l4 ornatus var4 didymus1 ,ibid4 ,pl4 ,,clxiii4 #ahej4 ,arancarites ,cordai1 ,unger1 ,genera et ,spec4 ,plant4 foss4 p4 #chb4 #ahge4 ,lepidostrobus variabilis1 ,feistmantel1 ,palaeontographica1 ,vol4 ,,lxiii4 ,pl4 ,,xliv4 #ahhf4 ,l4 variabilis1 ,kidston1 ,cat4 ,palaeozoic ,plants1 p4 #aig4 #ahij4 ,l4 ornatus1 ,zeiller1 ,flor4 ,valenciennes1 p4 #dig1 ,pl4 ,,lxxvi4 figs4 #e1 #f4 ---- ,l4 variabilis1 ,zeiller1 ,flor4 ,valenciennes1 p4 #dii1 ,pl4 ,,lxxvi4 figs4 #c1 #d4 ,under this specific name are included strobili from ,upper ,carboniferous rocks which1 in spite of minor differences1 may be considered as one type4 ,the cylindrical cones vary considerably in size1 some reaching a length of #ej cm4 or more4 ,the sporophylls are attached by a pedicel1 #d-h mm4 long1 at right angles to the axis1 while the distal portion forms an oval lanceolate limb #aj-bj mm4 in length4 ,the sporangia are #d-h mm4 long4 ,the branched example figured by ,lindley and ,hutton#dai as a variety 7,l4 ornatus var4 didymus7 illustrates a phenomenon not uncommon in both ,palaeozoic and recent lycopodiaceous strobili4 ,illustration3 ,,fig4 #aia4 ,lepidostrobus4 ,a-,d4 ,l4 oldhamius4 ,b1 ,c1 ,d4 ,from sections in the ,binney ,collection1 ,cambridge4 ,e4 ,megaspore4 7,after ,kidston47 ,f4 ,megaspore 7,coal-,measures1 ,halifax74 7,after ,williamson47 ,g4 ,megaspore of ,lepidostrobus foliaceus4 7,after ,mrs ,scott47 ,h4 ,tangential section of sporangium4 7,after ,bower47 ,i4 ,part of sporangium wall1 ,sm1 of the cone of ,lepidodendron ,veltheimianum1 enclosing two megaspores4 7,cambridge ,botany ,school47 ii4 ,lepidostrobus oldhamius ,williamson#dbj4 ,fig4 #aia1 ,a-,d4 ,williamson#dba instituted this term for strobili previously described by ,binney#dbb1 without adequate evidence1 as the cones of ,lepidodendron ,harcourtii4 ,in shape and in the main morphological features this type resembles ,l4 variabilis1 which is however known only in the form of casts and impressions4 ,a cone of ,l4 oldhamius1 #b-c cm4 in diameter1 possesses a medullated stele consisting of a ring of primary xylem 7fig4 #aia1 ,d1 x7 with exarch protoxylem and no secondary elements4 ,maslen found several short tracheae at the periphery of the xylem and states that these led him to compare the cone with the vegetative shoots of ,lepidodendron vasculare1 but the common occurrence of such elements in different types of shoot renders them of little or no specific value4 ,the inner cortex is like that of vegetative shoots of ,lepidodendron and the middle cortex1 which was no doubt of the type described in ,lepidostrobus ,brownii1 is represented by a gap in the sections1 beyond which is the stronger outer cortex 7fig4 #aia1 ,d7 passing into the horizontal pedicels of the sporophylls4 ,the section of the axis reproduced in fig4 #aia1 ,d1 was figured by ,binney#dbc as ,lepidodendron vasculare4 ,the leaf-traces1 several of which are seen in the middle cortical region in fig4 ,d1 lt1 consist of a strand of scalariform tracheae1 with a mesarch protoxylem1 succeeded by a few parenchymatous cells2 beyond these there is usually a small gap which was originally occupied by a strand of thin-walled cells4 ,it is important to note that in one sporophyll-trace figured by ,maslen#dbd there is a strand of thin-walled elongated elements abutting on the xylem1 which he describes as phloem4 ,this tissue is certainly more like true phloem than any which has hitherto been described in the leaf-traces of vegetative shoots4 ,the state of preservation is not1 however1 sufficiently good to enable us to recognise undoubted phloem features4 ,in such cones as ,i have examined no tissue has been seen which shows the histological features characteristic of the secretory zone of vegetative shoots3 the 8phloem0 7,maslen7 occupies the position in the sporophyll bundle which in the vascular bundles of foliage leaves is occupied by a dark-celled and partially disorganised tissue in continuity with the secretory zone of the main stele4 ,it may be that in the strobili this tissue occurred in a modified form1 but even assuming that the section figured by ,maslen shows true phloem1 an assumption based on slender evidence1 this is not sufficient justification for the application of the term phloem to a tissue occupying a corresponding position in vegetative shoots and distinguished by well-marked histological features4 ,the sporophyll-traces1 as seen in the outer cortex in fig4 #aia1 ,d1 are partially surrounded by a large crescentic space1 p1 which was originally occupied by the parichnos4 ,the sporangia are attached along the middle line of the sporophyll and1 as in ,lepidostrobus ,brownii1 a cushion of parenchyma projects into the lower part of the sporangial cavity 7fig4 #aia1 ,a1 a2 ,c1 a74 ,the diagrammatic sketch of part of a section in the ,binney ,collection reproduced in fig4 #aia1 ,b1 shows the position of the ligule1 l4 ,no megaspores have been discovered in any specimens of this type2 the microspores1 which occur both singly and in tetrads1 have a length of #jjb-jjc mm4 ,the drawing shown in fig4 #aia1 ,a1 based on a section in the ,binney ,collection1 illustrates the general arrangement of the parts of a typical ,lepidostrobus4 ,i have made use of this sketch instead of that given by ,maslen1 as his figure conveys the idea that the sporophylls are superposed1 whereas1 whether they are verticillate or spiral1 a radial longitudinal section would not cut successive sporangia in the same plane4 iii4 ,lepidostrobus ,brownii 7,brongn474 ,in #ahdc a specimen of a portion of a petrified cone was purchased by the ,british ,museum1 assisted by the ,marquis of ,northampton and ,robert ,brown1 for #cj from a ,french dealer4 ,this fossil1 from an unknown locality1 was briefly described by ,brown in #aheadbe and named by him ,triplosporites1 but in a note added to his paper he expressed the opinion that the generic designation ,lepidostrobus would be more appropriate4 ,brongniart afterwards named the cone ,triplosporites ,brownii#dbf1 and ,schimper#dbg described it in his ,trait as ,lepidostrobus ,brownii4 ,the type-specimen is preserved in the ,british ,museum and the ,paris ,museum possesses a piece of the same fossil4 ,the central axis of the cone has a stele of the type characteristic of ,lepidodendron fuliginosum and ,l4 ,harcourtii1 and the xylem is surrounded by a thin-walled tissue described by ,bower#dbh as possibly phloem2 but in the absence of longitudinal sections it is impossible to say how far the tissue external to the xylem agrees with that in ,lepidodendron stems4 ,the sporophylls consist of a horizontal portion1 to the upper face of which the radially elongated sporangia are attached1 one to each sporophyll2 beyond the distal end of the sporangium the sporophyll bends sharply upwards as a fairly stout lamina4 ,the wall of the sporangium is composed of several layers of cells1 as shown in a drawing published by ,bower#dbi2 in the interior occur groups of microspores1 and from a ridge of tissue which extends along the whole length of the sporangium irregular trabeculae of sterile tissue project into the sporangial cavity1 as in ,isoetes 7fig4 #aia1 ,h3 cf4 fig4 #acc1 ,h74 ,further information in regard to ,lepidostrobus ,brownii has recently been supplied by ,prof4 ,zeiller#dcj1 who recognises the existence of a ligule1 and draws attention to some interesting histological features in the tissue of the sporophylls#dca4 ,spores of ,palaeozoic ,lycopodiales4 ,the calcareous nodules from the ,coal seams of ,yorkshire and ,lancashire are rich in isolated spores1 many of which are undoubtedly those of ,lepidostrobi4 ,examples of spores were figured by ,morris#dcb in #ahdj1 and their occurrence in coal has been described by several authors1 one of the earliest accounts being by ,balfour#dcc4 ,the drawings of ,palaeozoic and recent spores published by ,kidston and ,bennie#dcd demonstrate a striking similarity between the megaspores of existing and extinct ,lycopods1 the chief difference being the larger size of the fossils4 ,the general generic name ,triletes1 originally used by ,reinsch#dce1 is a convenient term by which to designate ,pteridophytic spores which cannot be referred to definite types4 ,it is usual to find more than four megaspores in each megasporangium in ,palaeozoic and not infrequently1 as we have seen1 in ,mesozoic lycopodiaceous strobili1 but in some ,palaeozoic cones1 e4g4 ,bothrostrobus 7fig4 #baf7 and ,lepidostrobus foliaceus#dcf1 a single tetrad only appears to have reached maturity4 ,the occurrence of long simple or branched and sometimes capitate hairs is a common feature of ,carboniferous megaspores 7fig4 #aia1 ,e1 ,f1 ,i74 ,it is possible that these appendages served to catch the microspores1 thus facilitating fertilisation4 ,a peculiar form of megaspore has been described by ,mrs ,scott#dcg1 and assigned by her to ,lepidostrobus foliaceus1 the megasporangium of which apparently contained only four spores4 ,as shown in fig4 #aia1 ,g1 a large bladder-like appendage characterised by radiating veins is attached to the thick spore-coat2 it is suggested that this excrescence may be compared with the 8swimming0 apparatus of the recent water-fern ,azolla4 ,the epithet swimming which it is customary to apply to the appendages of ,azolla megaspores would seem to be inappropriate if ,campbell#dch is correct in stating that spores of ,azolla are incapable of floating4 ,b4 ,spencerites4 ,spencerites insignis 7,williamson74 ,fig4 #aib4 #ahgh4 ,lepidostrobus sp41 ,williamson1 ,phil4 ,trans4 ,r4 ,soc41 p4 #cdj1 ,pl4 ,,xxii4 #ahhj4 ,lepidostrobus insignis1 ,williamson1 ,phil4 ,trans4 ,r4 ,soc41 p4 #ejb1 ,pl4 ,,xv4 figs4 #h-ab4 #ahhi4 ,lepidodendron ,spenceri1 ,williamson1 ,phil4 ,trans4 ,r4 ,soc41 p4 #aii1 ,pl4 ,,vii4 figs4 #bj-bb2 ,pl4 ,,viii4 fig4 #ai4 #ahig4 ,spencerites insignis1 ,scott1 ,phil4 ,trans4 p4 #hc1 ,pls4 ,,xii-,,xv4 ,another type of lycopodiaceous strobilus1 differing sufficiently from ,lepidostrobus to deserve a special generic designation1 is that originally described by ,williamson#dci1 from the ,lower ,coal-,measures of ,yorkshire1 as a type of ,lepidostrobus1 ,l4 insignis1 but afterwards#ddj more fully investigated and assigned to a new genus by ,scott#dda4 ,it should be pointed out that in a later publication ,williamson spoke of the lycopodiaceous axis1 which he suspected might belong to his ,l4 insignis1 as possibly worthy of recognition as a distinct generic type4 ,illustration3 ,,fig4 #aib4 ,spencerites insignis 7,williamson74 7,after ,miss ,berridge47 ,of the two species included by ,scott in his genus ,spencerites only one1 ,s4 insignis1 need be considered4 ,since the publication of ,scott's paper our knowledge of this type has been extended by ,miss ,berridge#ddb and by ,prof4 ,lang#ddc4 ,the axis of the strobilus has a stele characterised by a pith of elongated elements1 most of which have thin walls2 the xylem cylinder possesses about twenty protoxylem strands forming more or less prominent exarch ridges4 ,the cortex exhibits a differentiation comparable with that in the shoots of ,lepidodendron4 ,the sporophylls are arranged in alternating verticils1 each whorl consisting of ten members3 the narrow horizontal pedicel of a sporophyll1 containing a single vascular bundle1 as shown in fig4 #aib1 is expanded distally into a prominent upper lobe bearing a cushion of small and delicate cells1 to which the sporangium is attached1 and prolonged obliquely upwards as a free leaf-like lamina4 ,the lower blunt prolongation of the sporophylls appears to form a thick dorsal lobe1 but1 as ,lang has pointed out1 it is highly probable that the present form of the dorsal lobe is of secondary origin1 and is 8due to the disappearance of a mucilage cavity from a large sporophyll base#ddd40 ,as ,miss ,berridge remarks1 the vascular bundle of the sporophyll does not give off a branch to the ventral lobe and sporangium4 ,in attachment1 in shape1 and in the structure of the wall the sporangia differ markedly from those of ,lepidostrobi4 ,the spores1 which also constitute a characteristic feature of the genus1 have a maximum diameter of #jad mm42 they are described as oblate spheroids with a broad hollow wing running round the equator 7fig4 #aib7 comparable with the air-sacs of the pollen of ,pinus4 ,scott points out that the spores of ,spencerites are intermediate in size between the microspores of ,lepidodendron and the megaspores of ,lycopodium2 it is difficult therefore to decide to which category they should be referred4 ,spencerites is clearly distinct from ,lepidostrobus2 the absence of a ligule1 the manner of attachment of the sporangia1 and the form and size of the spores1 are characteristic features4 ,a comparison of ,spencerites with the strobili of ,lycopodium cernuum 7figs4 #abc1 #abf-abi7 has recently been made by ,lang1 who draws attention to the striking agreement as regards general plan and even detailed structural features between the ,palaeozoic and the recent type of strobilus4 ,it is interesting to find1 as ,lang points out1 that in the original account of the fossil cone by ,williamson1 the view is expressed that the sporangiophores were confluent4 ,an examination of the section figured by ,williamson#dde led ,lang to confirm this opinion4 ,it would be out of place to enter here into a detailed comparison of ,spencerites insignis and the cone of ,lycopodium1 but the resemblances are considered by ,lang to be sufficiently close to suggest that the striking similarity may be indicative of relationship#ddf4 ,it is worthy of notice that the radial section of ,spencerites 7fig4 #aib7 presents a fairly close resemblance to a corresponding section through a cone-scale of ,agathis 7,kauri ,pine7#ddg4 ,in each case the megasporangium is attached by a narrow pedicel to the sporophyll and the latter has a similar form in the two plants1 though the extent of the resemblance is somewhat lessened by ,lang's more complete account of the ,palaeozoic type4 ,if the ,spencerites sporangia possessed an integument the similarity with the ,agathis ovule would of course be much closer3 recent palaeobotanical investigations have shown that ovules and sporangia are not separated by impassable barriers4 ,since this ,chapter was set up in type a paper has appeared by ,dr ,bruno ,kubart on a new species of ,spencerites spore1 ,s4 membranaceus1 from the ,ostrau-,karwiner ,coal-basin 7,austria74 ,the spores are larger than those of ,s4 insignis and in some the cells of a prothallus are preserved4 ,kubart figures a section of a spore containing a group of seven cells1 a central cell1 which he regards as an antheridial mother-cell1 surrounded by six wall-cells4 ,kubart 7#ij74 ,,chapter ,,xvi4 ,sigillaria4 i4 ,general4 ,in view of the close resemblance between ,lepidodendron and ,sigillaria1 another lycopodiaceous plant characteristic of ,carboniferous and ,permian floras1 a comparatively brief description of the latter genus must suffice1 more particularly as ,lepidodendron has received rather an undue share of attention4 ,sigillaria1 though abundantly represented among the relics of ,palaeozoic floras1 especially those preserved in the ,coal-,measures1 is rare in a petrified state1 and our knowledge of its anatomy is far from complete4 ,in external form as in internal structure the difference between the two genera are not such as enable us to draw in all cases a clearly defined line of separation4 ,in the ,antediluvian ,phytology1 ,artis#ddh figured a fossil from the ,carboniferous sandstones of ,yorkshire which he called ,euphorbites vulgaris on account of a superficial resemblance to the stems of existing succulent ,euphorbias4 ,rhode#ddi also compared ,sigillarian stems with those of recent ,cacti4 ,the specimen described by ,artis is characterised by regular vertical and slightly convex ribs bearing rows of leaf-scars in spiral series1 like those on the cushions of ,lepidodendron4 ,a few years earlier ,brongniart#dej had instituted the genus ,sigillaria#dea for plants with ribbed but not jointed stems bearing 8disc-like impressions0 7leaf-scars7 disposed in quincunx2 the type-species named by the author of the genus ,sigillaria scutellata is identical1 as ,kidston#deb points out1 with ,euphorbites vulgaris of ,artis and with the plant afterwards figured by ,brongniart as ,s4 pachyderma#dec4 ,brongniart in #ahbb figured another type of stem characterised by the absence of ribs and by prominent spirally arranged cushions bearing relatively large leaf-scars like the upper part of the specimen shown in fig4 #bjc2 this he named ,clathraria ,brardii1 a well-known and widely distributed ,carboniferous and ,permian species now spoken of as ,sigillaria ,brardi 7figs4 #aif1 ,a-,c2 #bjc74 ,a third type of stem figured by ,brongniart as ,syringodendron striatum#ded agrees with ,sigillaria scutellata in having ribs1 but differs in the substitution of narrow oval ridges or depressions for leaf-scars2 this is now recognised as a partially decorticated ,sigillaria1 in which the vascular bundle of each leaf is represented by a narrow ridge or depression4 ,the name ,syringodendron1 originally used by ,sternberg1 is conveniently applied to certain forms of ,sigillarian stems which have lost their superficial tissues4 ,a fourth generic name1 ,favularia1 was instituted by ,sternberg#dee for ,sigillarian stems with ribs covered with contiguous leaf-scars of hexagonal form and prominent lateral angles 7fig4 #aic1 ,a2 fig4 #bjj1 ,g74 ,illustration3 ,,fig4 #aic4 ,a4 ,sigillaria elegans ,brongn4 ,b4 ,sigillaria rugosa ,brongn4 ,middle ,coal-,measures4 ,c4 ,omphalophloios anglicus ,kidst4 ,barnsley4 ,d4 ,sigillaria elegans ,brongn4 ,e4 ,sigillaria tessellata ,brongn4 7,a1 ,b1 ,c1 ,e1 about nat4 size4 ,dr ,kidston's ,collection47 ,the generic or sub-generic title ,rhytidolepis1 also instituted by ,sternberg1 is applied to ribbed ,sigillarian stems such as ,s4 scutellata1 ,s4 rugosa 7fig4 #aic1 ,b71 ,s4 mammillaris 7fig4 #aie71 or ,s4 laevigata 7fig4 #aif1 ,d74 ,goldenberg#def proposed the name ,leiodermaria for smooth ,sigillarian stems with leaf-scars not in contact with one another 7fig4 #aif1 ,c74 ,the shoot system of ,sigillaria consisted of a stout stem tapering upwards to a height of #ajj feet#deg or more as an unbranched column1 with its dome-shaped apex#deh covered with linear grass-like leaves or1 in some species1 such as ,sigillaria ,brardi#dei1 ,s4 ,eugenii#dfj1 etc41 the main trunk was occasionally divided by apparently equal dichotomy4 ,the younger portions of the stem or branches were in some species clothed with leaves separated by a narrow zigzag groove surrounding their hexagonal bases1 while in other forms each leaf was seated on a more or less prominent cushion having the form illustrated by ,sigillaria ,mc,murtriei 7fig4 #aid7 or by the example represented in fig4 #bjj1 ,h2 or as in the ribbed species shown in figs4 #aic1 ,b1 and #aie1 the leaves in vertical series were separated from one another by longer portions of the ribs4 ,as in ,lepidodendron the cushions are frequently characterised by irregular transverse wrinklings and other#dfa surface-ornamentation which in some instances at least may have been produced as the result of post-mortem shrinkage of superficial tissue4 ,from the rarity of shoots with the foliage attached1 it would seem that the leaves persisted for a comparatively short time and were cut off by an absciss-layer leaving behind a well-marked leaf-scar area4 ,the linear leaves1 reaching in rare cases a length of one metre 7e4g4 ,s4 lepidodendrifolia7 but usually much shorter1 possessed a single median bundle1 and the lower face was characterised by two stomatal grooves and a median keel4 ,it is not uncommon to find leaf-bases of ,sigillaria detached from the stem and preserved as separate impressions4 ,the term ,sigillariophyllum used by ,grand',eury#dfb may be applied to detached leaves1 though it is by no means easy to distinguish between the foliage of ,sigillaria and ,lepidodendron4 ,a comparison of a typical species of ,sigillaria1 such as ,s4 rugosa 7fig4 #aic1 ,b7 or ,s4 ,brardi 7fig4 #aif1 ,a-,c7 with a typical ,lepidodendron reveals obvious differences in the form of the leaf-cushion1 but in some cases the distinction becomes purely arbitrary4 ,illustration3 ,,fig4 #aid4 ,sigillaria ,mc,murtriei ,kidst4 ,from a specimen from the ,upper ,coal-,measures of ,radstock1 in the ,british ,museum 7,v4 #ieb74 ,nat4 size4 ,illustration3 ,,fig4 #aie4 ,sigillaria mammillaris4 7,rhytidolepis form47 ,from a specimen in the ,manchester ,museum4 p1 parichnos2 l1 ligule-pit2 t1 leaf-trace2 c1 cushion2 s1 leaf-scar4 ,illustration3 ,,fig4 #aif4 ,a-,c4 ,sigillaria ,brardi4 7,a after ,germar2 ,b1 ,c after ,zeiller47 ,d4 ,sigillaria laevigata4 ,e4 ,lepidodendron ,wortheni 7,d and ,e after ,zeiller74 ,immediately above the centre of the upper boundary of a ,sigillarian leaf-scar a ligule pit may often be detected1 as shown in fig4 #aie1 l1 and in some cases1 e4g4 a specimen figured by ,germar#dfc 7fig4 #aif1 ,a7 as ,sigillaria spinulosa 7identical with ,s4 ,brardi71 some circular scars with a central pit surrounded by a raised rim occur on the surface of the stem1 either singly or in pairs1 near the leaf-scars2 these1 it is suggested1 may represent the position of adventitious roots or1 as ,germar thought1 of some deciduous spinous processes4 ,the leaf-scars are frequently hexagonal in shape1 with the lateral angles either rounded 7fig4 #bjj1 ,f7 or sharply pointed 7fig4 #bjj1 ,g1 ,h72 each scar bears three smaller scars as in ,lepidodendron1 a central circular1 oval or crescentic leaf-trace scar and larger oval or slightly curved scars formed by the two parichnos arms 7fig4 #aie1 p74 ,the larger size of the parichnos arms1 the individual cells of which may often be detected as a fine punctation1 is a distinguishing feature of the genus1 but otherwise the structure is very similar to that in ,lepidodendron4 ,as shown in figs4 #aie1 #bjj1 ,f1 ,g1 the three scars may occur nearer the upper than the lower margin of the leaf-base area4 ,lepidodendron ,wortheni#dfd 7fig4 #aif1 ,e71 described from ,north ,america by ,lesquereux#dfe1 by ,zeiller#dff from ,france1 and by ,kidston#dfg from the ,upper and ,middle ,coal-,measures of ,england1 may be quoted as a ,lepidodendron bearing a close resemblance to ,sigillaria4 ,the shoots bear cushions two or three times as long as broad and without the usual median division1 but with numerous irregular and discontinuous transverse wrinklings4 ,lepidodendron ,peachii ,kidston#dfh affords another example of a form agreeing both with ,sigillaria and with ,lepidodendron4 ,an ,upper ,devonian type described by ,white#dfi as ,archaeosigillaria primaeva affords a striking instance of the combination on one stem of ,sigillarian and ,lepidodendroid leaf-cushions4 ,the difference between the original surface of a ,sigillaria stem and that of partially decorticated specimens is seen in figs4 #aif1 ,c and ,d2 in fig4 ,c the bark of ,sigillaria ,brardi shows the characteristic wrinklings of the superficial tissue1 while at a slightly lower level the leaf-scars are replaced by the parichnos casts1 a1 and fine longitudinal striations represent the elongated phelloderm cells laid bare by the exfoliation of the surface-layers4 ,similarly1 in the rib of ,sigillaria laevigata 7fig4 #aif1 ,d7 the parichnos arms1 p1 and the longitudinal striations are exposed at the lower level1 while the surface is smooth and bears rows of widely separated leaf-scars4 ,illustration3 ,,fig4 #aig4 ,carica sp4 ,from the ,royal ,gardens1 ,kew4 7,much reduced47 ,m4,s4 ,the older part of a ,sigillarian stem may present an appearance very different from that of the younger shoots4 ,the leaf-cushions may be stretched apart as the result of elongation and increase in girth1 while in some cases the arrangement of the leaf-scars may vary on the same axis as the result of inequalities in growth or changing climatic conditions4 ,the contiguous arrangement of the leaf-scars and narrow cushions characteristic of the ,clathrarian form of stem1 as was first demonstrated by ,weiss#dgj1 and afterwards illustrated by ,zeiller#dga and ,kidston1 may be gradually replaced 7on the same specimen7 by a more distant disposition of the leaf-scars separated by a smooth intervening surface of bark4 ,the specimen of ,s4 ,brardi reproduced in part in fig4 #bjc1 and first figured by ,kidston1 affords an example of three 8species0 on one piece of stem1 ,s4 ,brardi ,brongn41 ,s4 denudata ,goepp4 and ,s4 rhomboidea ,brongn4#dgb ,the piece of ,carica stem1 represented in fig4 #aig1 illustrates the danger of trusting to the disposition of leaves as a specific criterion4 ,similarly1 in the ribbed forms the degree of separation of the leaf-scars is by no means uniform in a single species#dgc4 ,some authors have adopted a two-fold classification of ,sigillarian stems proposed by the late ,prof4 ,weiss#dgd of ,berlin1 who divided the ,sigillariae into 7,a7 ,sub-,sigillariae1 comprising ,leiodermariae and ,cancellatae1 and 7,b7 ,eu-,sigillariae1 including ,favulariae and ,rhytidolepis4 ,grand',eury#dge adopts the terms ,rhytidolepis and ,leiodermaria for ribbed and smooth stems respectively1 the type to which the name ,clathraria was applied by ,brongniart being in some cases at least the young form of ,leiodermarian stems4 ,while recognising the artificial distinction implied by such terms as ,rhytidolepis1 ,leiodermaria1 and other sub-generic titles1 we may conveniently speak of the two main types of ,sigillaria stems as ribbed and smooth4 ,still older stems of ,sigillaria are not uncommon from which the leaf-scars and other superficial tissues have been exfoliated1 leaving exposed a longitudinally fissured surface of secondary cortex characterised by pairs of considerably enlarged parichnos strands 7fig4 #aih7 which are sometimes partially or wholly fused into one 7,syringodendron state of ,sigillaria74 ,the single or double nature of the elliptical or circular parichnos areas is doubtless due to the degree of exfoliation1 which may extend sufficiently deep into the cortex to reach the level of the parichnos before the single strand has bifurcated 7cf4 ,lepidodendron1 p4 #ajj74 ,in the ,museums of ,manchester1 ,newcastle1 and other places casts of large ,sigillaria stems may be seen1 which illustrate the differences in breadth and regularity of the vertical ribs1 and in the size and shape of the parichnos areas in different regions of a partially decorticated stem4 ,a cast of a ribbed species in the ,manchester ,museum1 having a length of #ahe cm4 and a breadth of #ef cm41 shows in the upper portion straight vertical grooves and broad ribs bearing pairs of parichnos scars #aa mm4 long2 in the lower portion the ribs tend to become obliterated and the parichnos scars1 #b cm4 in length1 may be partially fused and arranged in much less regular vertical series4 ,a feature of these older ribbed ,sigillarian stems is the increase in the number of the ribs from below upwards4 ,kidston#dgf has described a specimen in the ,sunderland ,museum1 #f feet #f inches long1 with a circumference at the slightly bottle-shaped base of #e feet4 ,on the lower portion of the stem there are #bi broad ribs2 about one-third the height many of these bifurcate1 producing as many as #dj ribs in the upper part where the cast has a circumference of #c feet4 ,the increase in number of the ribs is due in part to bifurcation1 but also to the intercalation of new ones4 ,as ,kidston points out1 this example shows that as a stem grew in length additional leaves were developed at the apex4 ,a similar stem1 which illustrates very clearly the increase in the number of ribs from below upwards1 may be seen in the ,newcastle ,museum4 ,grand',eury#dgg has described an example of an old stem of a ribless species of ,sigillaria1 ,syringodendron bioculatum1 bearing single and double parichnos areas of nearly circular form and with a diameter of #a-b cm4 ,in a specimen figured by ,renault and ,roche#dgh 7,syringodendron esnostense7 from the ,culm strata in ,france1 the parichnos scars reach a length of #c cm4 ,as seen in the fragment of a ribbed ,sigillaria represented in fig4 #aih1 the large parichnos areas exhibit a distinct surface pitting in contrast to the fine longitudinal striation of the rib2 the difference in surface-appearance is due to the nature of the tissue1 which in the parichnos consists of fairly large parenchymatous elements with groups of secretory cells#dgi1 and in the exposed cortex of elongated elements4 ,the vertical line in the middle of fig4 #aih1 which occurs in the middle of the rib1 has probably been formed by splitting of the bark4 ,illustration3 ,,fig4 #aih4 ,sigillaria with large parichnos areas4 7 nat4 size47 ,m4,s4 ,grand',eury's description of fossil forests of ,sigillariae in the rocks of the ,st tienne#dhj district affords a striking picture of these arborescent ,pteridophytes2 he speaks of the stems of some of the trees as swollen like a bottle at the base1 characterised by the ,syringodendron features and terminating below in short repeatedly forked roots of the type known as ,stigmariopsis4 ,other specimens of ,sigillaria stumps show a marked decrease in girth towards the base2 this tapered form is regarded by ,grand',eury as the result of the development of aerial columnar stems from underground rhizomes4 ,the nature of the root-like organs of ,sigillaria is dealt with in the sequel3 a brief reference may1 however1 be made to the occurrence of stumps of vertical trunks which pass downwards into regularly forked and spreading arms4 ,these arms lie almost horizontally in the sand or mud like the underground rhizomes of ,phragmites and other recent plants growing in swampy situations where water is abundant and where deeper penetration of the soil would expose them to an insufficient supply of oxygen#dha4 ,it is certain that ,sigillaria had no tap-root1 but was supported on spreading subterranean organs bearing spirally disposed long and slender rootlets which absorbed water from a swampy soil4 ,illustration3 ,,fig4 #aii4 ,partially decorticated stem of ,sigillaria showing two zones of cone-scars4 ,from a cast in the ,sedgwick ,museum1 ,cambridge4 ,m4,s4 7 nat4 size47 ,the regularity of the leaf-scar series on a ,sigillarian stem may be interrupted by the occurrence of oval scars with a central scar and surrounding groove 7fig4 #aic1 ,e72 these occur in zones at more or less regular intervals on the stem1 as seen in the partially decorticated cast represented in fig4 #aii4 ,zeiller has pointed out that the rows of oval or circular scars1 which mark the position of caducous stalked strobili1 may occur between the leaf-scars in vertical series1 each of which may include as many as #bj scars1 while in other cases a single series of such cone-scars may encircle the stem#dhb4 ,the zones are usually of uneven breadth1 as in ,s4 ,brardi1 and their occurrence produces some deformation of the adjacent leaf-scars4 ,by the earlier writers ,sigillaria was compared with succulent ,euphorbias1 ,cacti1 and ,palms2 ,brongniart#dhc at first included undoubted ,sigillarian stems among ,ferns1 but after investigating an agatized stem from ,autun1 he referred ,sigillaria to the ,gymnosperms#dhd on the ground that it had the power of producing secondary wood4 ,it was then supposed that ,lepidodendron possessed only primary xylem1 and that the presence of a vascular meristem in ,sigillaria necessitated its separation from the lycopodiaceous genus ,lepidodendron and its inclusion in the higher plants4 ,by slow degrees it was recognised1 as in the parallel case of the genus ,calamites1 that the presence or absence of secondary vascular tissue is a character of small importance4 ,williamson1 whose anatomical researches played the most important part in ridding the minds of palaeobotanists of the superstition that secondary growth in thickness is a monopoly of the ,phanerogams1 spoke in #ahhc of the conflict as to the affinities of ,lepidodendron and ,sigillaria as virtually over but leaving here and there 8the ground-swell of a stormy past#dhe40 ,in #ahgb the same author had written3 8,if then ,i am correct in thus bringing the ,lepidodendra and ,sigillariae into such close affinity1 there is an end of ,m4 ,brongniart's theory1 that the latter were gymnospermous exogens1 because the cryptogamic character of the former is disputed by no one2 we must rather conclude as ,i have done that the entire series represents1 along with the ,calamites1 an exogenous group of ,cryptogams in which the woody zone separated a medullary from a cortical portion#dhf40 ,in #ahgi ,renault#dhg expressed the opinion that ,brongniart by his investigation of the anatomy of ,sigillaria elegans had established in a manner 8presque irrfutable0 that ,sigillaria must be classed as a ,gymnosperm showing affinity with the ,cycads4 ,in #ahee ,goldenberg#dhh described some strobili which he regarded as those of ,sigillaria and recognised their close resemblance to a fertile plant of ,isoetes4 ,he was led to the conclusion1 which had little influence on contemporary opinion1 that ,sigillaria is related to ,isoetes and must be classed among ,pteridophytes4 ,to these long and narrow strobili ,schimper gave the name ,sigillariostrobus#dhi4 ,in #ahhd ,zeiller#dij supplied confirmation of ,goldenberg's view by the discovery of cones borne on pedicels with ,sigillarian leaf-scars1 thus demonstrating the generic identity of cones and vegetative shoots1 which ,goldenberg had connected on the evidence of association4 ,zeiller's more recent work#dia and the still later researches of ,kidston#dib have added considerably to our knowledge of the morphology of ,sigillarian cones4 ,grand',eury's remark made so recently as #ahijdic that opinion in regard to the ,gymnospermous nature of ,sigillaria is losing ground every day1 bears striking testimony to the pertinacity with which old beliefs linger even in the face of overwhelming proof of their falsity4 ,it is remarkable1 in view of the abundance of vegetative shoots1 how rarely undoubted ,sigillarian strobili have been found2 this may1 however1 be in part due to a confusion with ,lepidostrobi which so far as we know do not differ in important respects from ,sigillariostrobi#did4 ,there can be no doubt that ,sigillaria usually produced its cones on slender pedicels which bore a few leaves or bracts in irregular verticils1 or in short vertical series on comparatively stout stems1 an arrangement reminding us of the occurrence of flowers on old stems of ,theobroma and other recent ,dicotyledons4 ,as ,renault#die pointed out the fertile shoots are axillary in origin4 ,dr ,kidston#dif is of opinion that certain species of ,sigillaria bore cones sessile on large vegetative shoots characterised by two opposite rows of cup-like depressions like those in the ,ulodendron form of ,lepidodendron ,veltheimianum 7fig4 #aeg74 ,he has described the ,ulodendron condition of two species1 ,sigillaria discophora 7,knig7 and ,s4 ,taylori 7,carr472 the cup-like depressions may have a diameter of several centimetres and are distinguished from those of ,bothrodendron by the almost central position of the umbilicus4 ,the specimens which he figures as ,s4 discophora are identified by him with the stem figured by ,knig as ,lepidodendron discophorum and by ,lindley and ,hutton#dig as ,ulodendron minus4 ,we have already dealt with the nature of ,ulodendron shoots1 expressing the opinion that in spite of the often quoted specimen described by ,d',arcy ,thompson#dih1 in which a supposed cone occurs in one of the cups1 there is no satisfactory case of any undoubted cone having been found attached to the large ,ulodendron scars4 ,it is more probable that the ,ulodendron depressions represent the scars of branches1 either elongated axes1 or possibly in some cases deciduous tuberous shoots which served as organs of vegetative reproduction4 ,a specimen figured by ,kidston as ,sigillaria ,taylori from the ,calciferous sandstone of ,scotland#dii bears a row of slightly projecting 8appendicular organs0 attached to a ,ulodendron axis2 but these furnish no proof of their strobiloid nature4 ,the main question is1 are these ,ulodendron shoots correctly identified by ,kidston as ,sigillarian8 ,the surface of the specimens shows crowded rhomboidal scars surrounded in some cases by a very narrow border or cushion2 the general appearance is1 as ,kidston maintains1 like that of ,sigillaria ,brardi in which the leaf-scars are contiguous 7e4g4 fig4 #bjc1 upper part74 ,none of the leaf-scars exhibit the three characteristic features1 the leaf-trace and parichnos scars1 but only one small scar appears on each leaf-base area4 ,in a more recent paper ,kidston figures a small piece of a stem from ,kilmarnock1 which he identifies as ,sigillaria discophora1 showing the three characteristic scars on the leaf-base area4 ,there is no doubt as to the ,sigillarian nature of this specimen1 but it is not clear if the piece figured is part of a ,ulodendron shoot#ejj4 ,prof4 ,zeiller#eja retains the older name ,ulodendron minus ,lind4 and ,hutt4 in place of ,knig's specific designation and dissents from ,kidston's identification of ,ulodendron minus and ,u4 majus of ,lindley and ,hutton as one species2 he is also inclined to refer these ,ulodendron axes to ,lepidodendron4 ,in spite of the superficial resemblance to ,sigillaria of the specimens described by ,kidston1 and which ,i have had an opportunity of examining1 ,i venture to regard their reference to that genus as by no means definitely established4 ,we must recognise the difficulty in certain cases of drawing any satisfactory distinction between ,sigillaria and ,lepidodendron based on external features1 and while giving due weight to the conclusions of so experienced a palaeobotanist as my friend ,dr ,kidston1 ,i venture to think we are not in a position to state with confidence that ,sigillaria possessed ,ulodendron shoots4 ii4 ,leaves4 ,the leaves of ,sigillaria agree closely with those of ,lepidodendron2 they are either acicular 7fig4 #bjj1 ,d7 like ,pine needles or broader and flatter like the leaves of ,podocarpus4 ,their attachment to comparatively thick branches#ejb shows that they persisted1 in some cases at least1 for several years as in ,araucaria imbricata4 ,the lower surface of the lamina was characterised by a prominent keel 7fig4 #adb1 ,a and ,c7 which dies out towards the apex2 on either side of it are well-defined stomatal grooves 7figs4 #adb1 g1 g2 #adc1 ,a2 #bjj1 ,d1 g74 ,the upper face may be characterised by another groove 7fig4 #adb1 ,b7 but without stomata4 ,the occurrence of the stomatal grooves1 the abundance of transfusion tracheae 7fig4 #adb1 t7 surrounding the vascular bundle1 and the presence of strengthening hypodermal tissue suggest that the leaves of ,sigillaria were of a more or less pronounced xerophilous type and had a fairly strong and leathery lamina4 ,the mesophyll tissue consists either of short parenchymatous cells or of radially elongated palisade-like elements and has the loose or lacunar arrangement characteristic of the aerating system in recent leaves2 the slight development or absence of palisade-tissue may indicate exposure to diffuse light of no great intensity4 ,in most species there is a single vein1 but in others the xylem forms a double strand 7fig4 #adb1 ,b74 ,sections of the lamina near the apical region present a more circular form1 owing to the gradual obliteration of the upper groove and lower keel and to the dying out of the stomatal grooves4 ,the transverse section of the leaf diagrammatically represented in fig4 #adb1 ,a1 ,a1 shows the two stomatal grooves1 g1 and a prominent keel2 the single vein consists of a small group of primary tracheae1 x1 some delicate parenchyma1 and a brown patch of imperfectly preserved tissues1 a1 resembling the secretory zone tissue of a ,lepidodendron4 ,the whole is surrounded by a sheath of rather wide and short thinner-walled spiral or reticulate tracheids1 which may be spoken of as transfusion tracheae1 t1 and compared with similar elements in the leaves of many recent ,conifers4 ,to this tissue ,renault applies the epithet 8water-bearing0 and it is very likely that this may have been its function4 ,the shaded portions of the lamina1 in fig4 #adb1 ,a1 represent the distribution of thicker-walled hypodermal tissue4 ,the section of a leaf #c mm4 wide shown in fig4 #adb1 ,c1 shows an almost identical structure2 the transfusion tracheae are richly developed especially on the sides and lower surface of the vascular strand4 ,this leaf occurs in association with a petrified stem of ,sigillaria scutellata#ejc4 ,illustration3 ,,fig4 #bjj4 ,a4 ,sigillaria ,brardi ,s4 elegans ,brongn4 7#ci74 ,transverse section of stem4 ,b4 ,sigillaria ,brardi ,s4 spinulosa1 ,renault and ,grand',eury 7#ge73 c1 outer cortex2 x1 x1 xylem4 7,after ,renault and ,grand',eury47 ,c4 ,s4 ,brardi1 primary xylem element4 7,a and ,c after ,brongniart47 ,d4 ,leaf of ,sigillaria ,brardi3 g1 g1 stomatal grooves2 ep1 piece of epidermis of stem4 7,after ,renault47 ,e4 ,sigillaria ,brardi4 ,tangential section of leaf-bases3 p1 parichnos4 7,after ,renault47 ,f1 ,g1 ,h4 ,sigillaria leaf-scars and cushions4 7,after ,weiss47 ,renault#ejd has shown that the leaf-traces of ,sigillaria spinulosa 7 ,s4 ,brardi7 are accompanied in the outer cortical region of the stem by a fairly large amount of secondary xylem2 in sections of the free lamina which he figures the secondary elements are much less obvious and represented by a few tracheae only4 ,similarly1 in the leaf-base of ,s4 ,brardi 7fig4 #bjj1 ,e7 the xylem consists of both primary and secondary elements 7x1 x71 but in the lamina the latter is poorly if at all represented4 ,in the lamina of the leaves of ,s4 ,brardi the primary xylem forms a narrow slightly curved band with two lateral groups of narrower1 presumably protoxylem elements2 this is surrounded by delicate parenchyma styled by ,renault1 on very slender evidence1 phloem 78liber074 ,some dark cells below the xylem are described as sclerous tissue1 and surrounding the bundle is a sheath of transfusion tracheae 7dotted area in fig4 #bjj1 ,e74 ,it is possible that the elements spoken of with hesitation by ,renault as secondary xylem are transfusion tracheae4 ,there has probably been some confusion in the minds of authors between sclerous tissue and dark secretory tissue in ,sigillarian leaves2 the crescentic band1 a1 shown in fig4 #adb1 ,b1 which corresponds in position with the sclerous tissue of ,renault in ,s4 ,brardi leaves1 appears to be of the nature of secretory tissue4 ,the diagram shown in fig4 #adb1 ,b1 illustrates a type of leaf very like those already described1 except that there are two xylem strands1 x4 ,the difference between the double strand and the single bundle seen in figs4 #adb1 ,a1 ,c and #bjj ,e1 is comparatively small1 but it is a real distinction4 ,this type of leaf 7fig4 #adb1 ,b7 was originally described by ,renault#eje under the generic title ,sigillariopsis4 ,the genus was founded on a ,french petrified specimen consisting of part of a ribbed stem possessing a stele of the ,sigillarian type and characterised by separate primary xylem strands1 like those of ,s4 ,brardi described by ,brongniart in #ahci4 ,renault considered the presence of two xylem strands in the leaf a sufficient reason for the institution of a new genus and named the specimen ,sigillariopsis ,decaisnei4 ,prof4 ,bertrand of ,lille kindly photographed for me ,renault's type-specimen and sent several prints with explanatory notes4 ,the transverse section of the leaves shows very clearly the two xylem strands2 each strand consists of a triangular group of primary tracheae with the protoxylem apex pointing towards the lower surface of the lamina4 ,below each primary strand of centripetal xylem is an arc composed of a few small tracheae which ,renault and ,bertrand describe as secondary xylem2 it is1 however1 not clear from the photomicrographs that these are of secondary origin1 their position and appearance reminding one of the primary centrifugal xylem of a cycadean foliar bundle4 ,below this centrifugal xylem is another arc of imperfectly preserved elements described by ,renault as a protective sheath and by ,bertrand as glandular tissue2 the latter term is probably the more correct as the tissue may well correspond to the secretory-zone tissue of ,lepidodendron stems4 ,fairly large groups of transfusion tracheids occur on the flanks of the xylem4 ,prof4 ,bertrand points out that one of his sections1 cut nearer the apex of a leaf than that figured by ,renault with a single xylem strand1 contains a double strand and thus shows the latter's description to be an incorrect interpretation of the imperfectly preserved tissues4 ,the ,sigillariopsis type of leaf was recognised by ,scott#ejf in ,english material on which he founded the species ,sigillariopsis sulcata4 ,in a section which he has recently figured#ejg a lacuna below the two xylem strands is described as 8representing secretory tissue02 a band of transfusion tracheae almost encircles the pair of bundles4 ,in a note published in #aijg1 ,kidston#ejh demonstrated the association of ,sigillariopsis leaves with an undoubted ,sigillarian stem of the ,rhytidolepis type and expressed his conviction that ,renault's genus is identical with ,sigillaria4 ,the correctness of ,kidston's conclusion has been proved by ,arber and ,thomas#eji who found that the leaf-traces of ,sigillaria scutellata bifurcate during their course through the outer region of the cortex and enter the leaf as two distinct strands of primary xylem4 ,in the section from ,dr ,kidston's collection shown in fig4 #adb1 ,b1 the lamina1 #d mm4 wide1 consists mainly of thin-walled assimilating tissue composed of radially elongated cells abutting at the periphery on hypodermal mechanical tissue1 except at the edges of the stomatal grooves which are bounded by the small-celled epidermis4 ,a broad sheath of thicker-walled elements1 s1 surrounds numerous scattered transfusion tracheae1 t1 and below the two xylem strands1 x1 which are embedded in delicate parenchyma there is a crescentic band of dark tissue1 a1 resembling the smaller strand1 a1 in fig4 #adb1 ,a1 and the secretory zone tissue of a ,lepidodendron stem4 iii4 ,fertile shoots of ,sigillaria4 ,reference has already been made to the manner of occurrence of strobili on ,sigillarian stems2 it remains to describe the structure of these reproductive shoots4 ,sigillariostrobus1 the name given to ,sigillarian strobili1 may be defined in general terms as follows3 ,cylindrical cones1 rarely dichotomously branched#eaj as in species of ,lycopodium and ,selaginella1 which may reach a length of #cj cm4 7e4g4 ,sigillariostrobus nobilis ,zeill4#eaa7 and a diameter #b-e cm42 peduncle long and slender1 sometimes bearing acicular bracts or1 after leaf-fall1 characterised by leaf-cushions and leaf-scars like those on vegetative shoots 7fig4 #bja1 ,e74 ,the stalked cones are borne in irregular verticils and in some species in vertical series1 the fertile zones being separated by comparatively long sterile portions of the stem 7fig4 #aii74 ,the cones were deciduous and1 in certain cases if not in all1 the individual sporophylls became detached from the cone-axis on maturity4 ,the slender axis bore spiral or verticillate imbricate sporophylls attached at right angles or more or less obliquely4 ,the basal rhomboidal portion bore spores on its upper surface 7fig4 #bja1 ,f71 presumably enclosed in a somewhat radially elongated sporangium 7fig4 ,b7 and was prolonged distally into a narrow lanceolate free portion1 in some species with a ciliate border 7fig4 ,d74 ,the sporangia probably produced megaspores and microspores1 but such spores as have been recognised appear to belong to the former category4 ,the designation ,triletes is applied to isolated spores of ,sigillaria or to those of ,lepidodendron4 ,sigillariostrobus ,tieghemi ,zeiller#eab 7figs4 #bja1 ,e1 ,f74 ,in this species1 from the ,coal-field of ,valenciennes1 the pedicel bore acicular leaves or bracts attached to the upper portion of leaf-cushions arranged in vertical series 7fig4 ,e74 ,the cones reached a length of #af cm4 and a breadth of #be-e cm42 the sporophylls are borne in alternating verticils with #h-aj in each whorl4 ,several megaspores 7#b mm4 in diameter7 appear to have been produced in tetrads in each sporangium4 ,illustration3 ,,fig4 #bja4 ,sigillariostrobus4 ,a1 ,c4 ,sigillariostrobus rhombibracteatus ,kidst4 7,after ,kidston47 ,a4 ,portion of strobilus4 ,c4 ,megaspore4 ,b1 ,d4 ,sigillariostrobus ciliatus ,kidst4 7,after ,kidston47 ,e1 ,f4 ,sigillariostrobus ,tieghemi ,zeill4 7,after ,zeiller47 ,sigillariostrobus rhombibracteatus ,kidston#eac4 ,fig4 #bja1 ,a1 ,c4 ,kidston described this species from the ,middle ,coal-,measures of ,england3 it is similar in habit and in the form of the sporophylls to ,s4 ,tieghemi1 but rather smaller1 and the more definitely rhomboidal sporophylls have a ciliate margin4 ,the cone was probably heterosporous1 but megaspores alone have so far been discovered4 ,the sporophylls bear a close resemblance to those of ,lycopodium cernuum 7fig4 #abf1 ,c74 ,in some of the illustrations of this type given by ,kidston the naked cone-axis with its numerous sporophyll-scars is clearly shown1 reminding one of the naked axes of the cones of the ,silver ,fir 7,abies pectinata7 or ,cedar after the fall of the scales4 ,our knowledge of ,sigillarian cones is too incomplete to admit of a detailed comparison with the strobili of ,lepidodendron or with those of recent ,pteridophytes4 ,there can1 however1 be little doubt that ,goldenberg#ead was correct in his selection of ,isoetes as the most nearly allied recent plant so far as the fertile leaves are concerned4 ,it would seem that the sporangia were comparatively delicate structures which have left no clearly defined remains of their walls in the carbonised specimens2 ,kidston1 indeed1 speaks of the hollow bases of the sporophylls as holding the spores1 but this is hardly likely to have been the case4 ,our knowledge of the anatomy of ,sigillariostrobus is practically nil1 but in one specimen of a ,sigillaria elegans stem ,kidston#eae describes the structure of the tissues as seen in a transverse section of a scar of a fertile shoot2 from this we learn that the stele was composed exclusively of primary tracheids forming a solid strand without a pith4 ,it is probable that the cones of ,sigillaria were heterosporous1 but in no instance have undoubted microspores been discovered2 the megaspores in each megasporangium were fairly numerous as in ,isoetes 7fig4 #acc1 ,e74 ,in one species1 ,sigillariostrobus major 7,germar71 from ,permian rocks of ,france and ,germany1 ,zeiller#eaf states that the whole of a single cone bore megaspores 7#jh-a mm4 in diameter7 only2 this is1 however1 not opposed to the idea of heterospory1 as we find instances in ,selaginella of strobili bearing one kind of spore only 7cf4 p4 #ef74 ,in a few instances1 it has been possible to correlate cones with certain species of ,sigillaria1 but in most cases the strobili occur as isolated fossils4 iv4 ,the structure of ,sigillarian stems4 ,the first account of the anatomy of ,sigillaria we owe to ,brongniart#eag who published a description of the internal structure of an agatised stem1 about #d cm4 in diameter1 from ,autun1 which he referred to ,sigillaria elegans4 ,it has1 however1 been shown by ,zeiller#eah and by ,renault that this petrified fragment belongs to ,brongniart's species ,s4 ,menardi1 which is probably a young form of ,s4 ,brardi4 ,brongniart's specimen1 now preserved in the ,paris ,natural ,history ,museum1 is a very beautiful example of a silicified plant3 on part of the surface are preserved the hexagonal contiguous leaf-scars1 like those shown in fig4 #aic1 ,a1 and on the polished transverse section is seen a relatively large stele consisting of a ring of secondary xylem surrounding a series of crescentic groups of primary xylem 7fig4 #bjj1 ,a7 enclosing a wide pith occupied by concentric layers of silica4 ,a portion of the outer cortex is preserved1 and this is separated from the stele by a broad space filled with siliceous rock4 ,the main features of this type may be described in a few words4 ,the primary xylem differs from that of such ,lepidodendron stems as have been described in being made up of groups of scalariform and occasionally reticulate 7fig4 #bjj1 ,c7 tracheae1 having a plano-convex or more or less crescentic form as seen in transverse section4 ,these primary strands1 in contact with one another laterally1 have their narrowest elements on the outer edge4 ,the leaf-traces are given off from the middle of the abaxial face of each xylem strand 7fig4 #bjb1 ,c1 lt72 these pass obliquely outwards through medullary rays and then1 as in ,lepidodendron1 turn sharply upwards before bending outwards again on their way to the leaves4 ,each leaf-trace consists of a group of primary tracheae to which a few secondary tracheae are added during the passage through the secondary wood4 ,the secondary xylem forms a continuous cylinder of tracheae with scalariform bands on both radial and tangential walls2 the medullary rays are numerous and consist of long and narrow series1 usually one cell broad1 of parenchymatous cells with occasional short rays one or more cells in depth4 ,the slightly greater breadth of the rays between each primary xylem strand tends to divide the secondary wood into bundles corresponding in breadth to the primary groups4 ,the outer cortex closely resembles that of ,lepidodendron2 it consists internally of radial series of secondary1 elongated and rather stout1 elements abutting on the parenchymatous tissue of the leaf-cushions4 ,the next contribution to our knowledge of the anatomy of ,sigillaria was made by ,renault and ,grand',eury#eai who described the structure of ,sigillaria spinulosa ,germar#ebj1 a species now recognised as the ,leiodermarian condition of ,s4 ,brardi1 and probably1 therefore1 not specially distinct from the specimen described by ,brongniart in #ahci as ,s4 elegans4 ,in ,brongniart's fossil the leaf-cushions are in contact 7,clathrarian form of ,s4 ,brardi3 fig4 #bjc1 upper part7 whereas in the specimen now under consideration the leaf-scars are further apart 7,leiodermarian form of ,s4 ,brardi1 fig4 #bjc1 lower part1 and fig4 #aif1 ,c74 ,it may be1 as ,scott suggests1 that these two specimens are not specifically identical but closely allied1 an opinion based on certain anatomical differences#eba2 we may1 however1 include both under the comprehensive name ,s4 ,brardi4 ,the primary xylem 7fig4 #bjj1 ,b1 x71 is in some regions separated into distinct strands1 in others it forms a continuous band equal in length to several of the separate groups4 ,this type of stele1 in which the primary xylem consists in part of separate strands and in part of a continuous cylinder1 forms a transition between that represented in fig4 #bjj1 ,a1 and the steles of ,sigillaria elegans 7fig4 #bjb1 ,a7 and most species of ,lepidodendron4 ,the tendency of the primary xylem strands to become united laterally1 forming broader bands1 was first described by ,solms-,laubach#ebb in a ,french specimen of ,sigillaria spinulosa in the ,williamson collection4 ,the leaf-traces arise from the middle of the concave outer face of the primary xylem groups4 ,the inner cortex is composed of small parenchymatous cells as in ,lepidodendron1 and it is noteworthy that traces of partially disorganised tissue1 described as large canals1 in the region external to the secondary wood1 bear a resemblance#ebc to the secretory tissue of ,lepidodendron4 ,other interesting features are presented by the structure of the outer cortex and the parichnos4 ,the outer cortex in the leaf-scar region is composed of parenchyma1 but for the most part it consists of radially elongated groups of thin-walled parenchyma enclosed in a framework of thicker-walled and elongated elements 7fig4 #bjj1 ,b1 c74 ,this type of cortex1 to which ,brongniart applied the name ,dictyoxylon1 would produce a cast in the case of a partially decorticated stem characterised by a surface formed of irregularly oval and raised areas bounded by narrow grooves2 the greater prominence of the former being due to the more rapid decay of the softer tissue1 which would produce depressions on the exposed face of the dead stem4 ,casts of this type are not uncommon in ,carboniferous rocks1 and while some may belong to the ,pteridosperm ,lyginodendron1 others may be those of ,sigillarian stems4 ,illustration3 ,,fig4 #bjb4 ,a4 ,sigillaria elegans ,brongn4 7,section in ,dr ,kidston's ,collection cut from the specimen shown in fig4 #aic1 ,d47 ,b1 ,c4 ,sigillaria elongata ,brongn4 lt1 leaf-trace4 7,from specimens in the collection of ,prof4 ,bertrand47 ,the large parichnos-strands1 produced as in ,lepidodendron1 by the forking of a single strand arising in the middle cortical region1 consist in part of tissue containing secretory canals1 a structure like that recently described by ,miss ,coward#ebd in the large parichnos strands of ,syringodendron stems4 ,an example of a decorticated specimen is described by ,renault#ebe as ,sigillaria xylina4 ,this stem is presumably referred to ,sigillaria because the primary xylem consists of separate strands4 ,it is characterised by the unusually large development of secondary wood and by the relatively small size of the pith4 ,the xylem cylinder has a diameter of #d-e cm4 and the pith is only #d-e mm4 in breadth4 ,another example of a petrified ,sigillaria stem has been described by ,kidston#ebf as ,s4 elegans ,brongn4#ebg 7fig4 #aic1 ,d71 a species characterised by vertical rows of sub-hexagonal and contiguous leaf-scars and by the presence of verticils of cone-scars4 ,fig4 #aic1 ,d1 represents ,kidston's specimen in surface-view2 one row of leaf-scars is shown1 but most of the superficial tissues have been destroyed4 ,the crushed stele1 #ac mm4 in its longest diameter1 has a continuous cylinder of primary xylem1 7fig4 #bjb1 ,a1 x7 characterised by a regularly crenulate outer margin with the smallest elements at the edge2 the prominent ridges separating the sinuses are rounded4 ,the leaf-traces arise from the bottom of each sinus2 the leaf-bundles are mesarch1 and consist exclusively of primary elements4 ,the secondary xylem1 x1 like that of the primary xylem1 has a crenulate outer edge4 ,the most interesting feature of the outer cortex is afforded by a tangential section which1 in addition to the leaf-scars1 cuts through a cone-scar showing a solid primary stele surrounded by the cortex of the cone-peduncle4 ,another type of ,sigillaria1 probably ,s4 elongata ,brongn4 7fig4 #bjb1 ,b1 ,c71 which is very similar to ,s4 scutellata has been briefly described by ,prof4 ,bertrand#ebh1 to whom my thanks are due for the two photographs reproduced in fig4 #bjb1 ,b41 ,c4 ,his specimen1 from the ,pas de ,calais ,coal-field1 shows a ribbed ,rhytidolepis form of surface 7fig4 #bjb1 ,b74 ,the stele 7fig4 #bjb1 ,c7 agrees closely with that of ,s4 elegans as described by ,kidston1 but the ridges on the fluted surface of the primary xylem are more pointed4 8,in the immediate neighbourhood of the origin of a leaf-trace1 the spiral elements form a median band in the middle of a sinus0 and from this the leaf-traces are given off4 ,no secondary xylem was found in the leaf-traces at any part of their course4 ,bertrand compares the stele of ,s4 elongata with that of the type of ,lepidodendron represented by the ,burntisland species named by ,williamson ,l4 brevifolium 7fig4 #ahf7 and now usually referred to ,l4 ,veltheimianum2 the chief distinguishing features are the greater prominence in the ,french species of the surface-ridges or teeth of the primary xylem1 a feature which occurs in ,l4 ,wnschianum1 and the detachment of the leaf-traces from the bottom of each sinus 7fig4 #bjb1 ,c1 lt7 instead of from the sides of the sinus4 ,it is1 however1 not clear how far this latter distinction is a real one2 in ,lepidodendron ,wnschianum the leaf-traces appear to arise1 as in ,sigillaria1 from the middle of each sinus4 ,other types of ribbed ,sigillaria stems have been briefly described by ,scott#ebi1 ,kidston#ecj1 and more recently1 by ,arber and ,thomas#eca4 ,the specimen described by ,scott agrees in the main with ,s4 elegans of ,kidston and with ,s4 elongata of ,bertrand4 ,kidston's sections of ,s4 scutellata show a continuous primary xylem cylinder with a slightly and irregularly crenulate outer margin4 ,it would seem that one important diagnostic character in ,sigillarian stems is afforded by the degree and form of the crenulations on the outer surface of the primary xylem4 ,s4 scutellata has been described also by ,arber and ,thomas2 these authors were the first to demonstrate the presence of a ligule and ligular pit on the leaf-base in a petrified stem1 and they also contribute the important fact that the leaf-traces in passing through the phelloderm bifurcate and enter the leaf as two distinct vascular strands4 ,this double bundle has been referred to in the description of ,sigillaria leaves4 7,page #bad47 ,although our knowledge of the anatomy of ,sigillaria has been considerably extended since ,williamson#ecb drew attention to our comparative ignorance of the subject1 there are several points on which information is either lacking or very meagre4 ,as regards the stele1 it is in all types so far investigated1 of the medullated type and constructed on the same plan as that of ,lepidodendron ,wnschianum1 ,l4 ,veltheimianum1 and other species4 ,secondary xylem was developed at an early stage of growth1 and its relation to the primary xylem1 from which as ,kidston points out in his description of ,s4 elegans1 it may be separated by a few parenchymatous elements1 is like that in ,lepidodendron4 ,the tendency of the outer face of the secondary xylem to present a crenulate appearance in transverse sections may1 as ,scott thinks#ecc1 be a feature of some diagnostic importance1 but this is not a constant character in the genus4 ,in origin and in their mesarch structure1 the leaf-traces closely resemble those of ,lepidodendron4 ,the earlier account of the structure of the leaf-traces of ,sigillaria1 which were described as possessing both centrifugal and centripetal wood1 led ,mettenius#ecd to draw attention to an important anatomical resemblance between this genus and modern ,cycads4 ,this comparison was1 however1 based on a misconception2 the ,cycadean leaf-trace1 consisting solely of primary wood1 is not strictly comparable with those of some species of ,sigillaria1 in which one part of the xylem is primary and another secondary4 ,the occasional presence of secondary xylem in ,sigillarian leaf-traces is matched in some ,lepidodendra#ece1 and cannot be accepted as a distinguishing feature4 ,the origin of the leaf-traces from the middle of the sinuses on the edge of the primary xylem is regarded as a difference2 in ,lepidodendron the leaf-traces are said to arise in some species from the sides of the crenulations2 but1 as already pointed out1 this is a distinction of doubtful value4 ,the division of the primary xylem into separate strands in some stems of ,sigillaria of the ,clathrarian and ,leiodermarian forms is a characteristic peculiarity2 but ,s4 spinulosa forms a connecting link between this type and the continuous arrangement of the xylem in ,s4 elongata and ,s4 elegans4 ,kidston#ecf has shown that the discontinuous primary xylem occurs in ,lower ,permian species1 a fact consistent with the view that the greater abundance of the centripetally developed wood1 characteristic of the older species1 represents a more primitive feature4 ,this is not merely a conclusion drawn from a consideration of geological age1 but it is in harmony with the view expressed by ,scott#ecg that as plants achieved greater success in producing secondary centrifugal wood1 the retention of any considerable quantity of primary xylem became superfluous4 ,as yet we know very little of the structure of the perixylic tissues of ,sigillaria1 but there is no sufficient reason for supposing that these differ in essentials from those in ,lepidodendron4 ,the middle and outer cortical tissues are practically identical in the two genera4 ,the parichnos is of the same type1 except that in ,sigillaria it reached greater dimensions in the outer part of its course4 ,v4 ,sigillaria ,brardi#ech ,brongniart4 ,figs4 #aif1 ,a-,c2 #bjj2 #bjc4 #ahbb4 ,clathraria ,brardi1 ,brongniart1 ,classif4 ,vg4 foss41 ,pl4 ,,xii4 fig4 #e4 #ahbh4 ,sigillaria ,brardi1 ,brongniart1 ,hist4 ,vg4 foss4 p4 #dcj1 ,pl4 ,,clviii4 fig4 #d4 ,s4 ,menardi1 ibid4 ,pl4 ,,clviii4 #ahcf4 ,lepidodendron ,ottonis1 ,goeppert1 ,fossil ,farnkr4 ,pl4 ,,xlii4 #ahci4 ,s4 elegans1 ,brongniart1 ,arch4 ,mus4 ,nat4 ,hist4 ,paris1 ,vol4 ,i4 p4 #djf1 ,pl4 ,,xxv4 #ahdi4 ,s4 spinulosa1 ,germar1 ,verstein4 ,wettin und ,lbejn1 p4 #ei1 ,pl4 ,,xxv4 #ahic4 ,s4 mutans1 ,weiss1 ,abhand4 ,preuss4 ,geol4 ,anst4 ,n4,f4 ,heft #b1 ,pl4 ,,viii4 ,illustration3 ,,fig4 #bjc4 ,sigillaria ,brardi ,brongn4 7 nat4 size74 ,from a photograph of a specimen in ,dr ,kidston's collection1 from the ,upper ,transition ,series of ,staffordshire4 ,published by ,kidston 7#jb7 ,pl4 ,,lix4 fig4 #a4 ,the aerial shoots of this species are occasionally branched dichotomously#eci1 the apical portions bearing short crowded leaves#edj2 the surface of the bark is either completely covered with contiguous leaf-scars without definite leaf-cushions or with projecting cushions forming a narrow sloping surface surrounding each leaf-scar4 ,other parts of the plant may possess cushions similar in their kite-shaped form to those of ,lepidodendron1 but without a median vertical groove1 or the leaf-scars may be spirally disposed at varying distances apart on a comparatively smooth and longitudinally wrinkled bark4 ,the species exhibits striking instances of a transition between the ,favularian1 ,clathrarian1 and ,leiodermarian forms of stems4 ,the leaf-scars1 which are hexagonal in outline1--the lateral angles pointed and transversely elongated1 the upper and lower angles rounded1--bear three scars1 the central leaf-trace and two straight or curved lateral parichnos scars2 a ligular pit occurs immediately above the centre of the upper edge of the leaf-scar and occasionally circular elevations with a central pit occur singly or in pairs below a leaf-scar 7fig4 #aif1 ,a74 ,the linear leaves1 which may persist on shoots having a fairly large diameter#eda1 have a single median vein and two stomatal grooves on the lower surface#edb 7fig4 #bjj1 ,d74 ,partially decorticated and younger shoots are characterised by the occurrence of pairs of elliptical parichnos areas and a smaller median leaf-trace scar4 ,the surface of older stems1 which may show signs of longitudinal splitting 7,syringodendron state71 bears pairs of parichnos scars reaching a length of #b-be cm4 and a breadth of #aj-ac mm4 ,the regularity of the leaf-scar arrangement is interrupted at intervals by the occurrence of more or less regular verticils of scars marking the position of deciduous shoots4 ,grand',eury#edc has figured cones which he believes to be those of this species1 and ,zeiller refers the large strobili1 ,sigillariostrobus major1 to ,sigillaria ,brardi#edd4 ,the subterranean axes were characterised by spirally disposed rootlet-scars like those of ,stigmaria ficoides 7figs4 #bjd1 #bje7 and by a cortical surface with the features of ,stigmaria rimosa ,gold4#ede ,the anatomy of the stele and leaves has already been described 7p4 #bai74 ,the stele of the ,stigmarian portion of the plant consists of a band of centripetal primary xylem and a cylinder of centrifugally formed secondary wood with medullary rays containing vascular bundles passing out to the rootlets#edf4 ,sigillaria ,brardi occurs not uncommonly in ,permian rocks2 it is recorded from ,france#edg1 ,germany#edh1 ,pennsylvania#edi1 and elsewhere4 ,it is found in the ,upper1 ,middle1 and ,lower ,coal-,measures of ,england#eej and in ,permo-,carboniferous strata in ,africa#eea and ,brazil#eeb4 ,,chapter ,,xvii4 ,,underground ,,rhizomes ,,and ,,roots ,,of ,,palaeozoic ,,lycopodiaceous ,,plants4 ,stigmaria4 ,stigmaria ficoides is the name given to cylindrical casts met with in ,palaeozoic rocks1 from the ,devonian#eec to the ,permian#eed1 characterised by a smooth or irregularly wrinkled surface bearing spirally disposed circular scars bounded by a raised rim and containing a small central pit4 ,it is not uncommon to find evidence of a partial collapse of the substance of the plant as seen in fig4 #bjd2 this is doubtless the expression of a shrinkage of the middle cortical region1 which was composed of a delicate and lacunar system of cells4 ,there can be no reasonable doubt that ,stigmaria grew in water or in swampy ground4 ,specimens are occasionally met with in which the cast terminates in a bluntly rounded apex2 such are1 perhaps1 young branches which have not grown far from the base of the aerial stem from which they arose 7cf4 fig4 #bjg1 ,b1 ,c74 ,other examples occur1 such as ,goeppert#eee figured and ,gresley#eef has more recently described1 which are twisted and distorted as though obstacles had been encountered in the ground in which they grew4 ,illustration3 ,,fig4 #bjd4 ,stigmaria ficoides ,brongn4 ,m4,s4 7,see ,vol4 ,i4 p4 #gc47 ,illustration3 ,,fig4 #bje4 ,stigmaria ficoides4 ,from a specimen in the ,york ,museum1 from ,bishop ,auckland4 a1 base of rootlet showing vascular bundle scar4 ,m4,s4 ,the circular scars mark the bases of long single and occasionally forked appendages 7rootlets7 which spread on all sides into the surrounding medium 7figs4 #bje1 #bjh74 ,the occurrence of rootlets radiating through the shale or sandstone affords proof that the ,stigmarias are often preserved in their position of growth4 ,this was recognised by ,steinhauer#eeg and ,logan#eeh1 and has been more recently emphasised by ,potoni#eei as an argument in favour of the view that the beds containing such specimens are old surface-soils4 ,stigmaria usually shows regular dichotomous branching1 the arms spreading horizontally or slightly downwards and always arising from four main branches in the form of a cross 7fig4 #bjg74 ,the most remarkable specimens found in ,england are described by ,williamson#efj in his monograph of ,stigmaria4 ,one of two large casts found near ,bradford in ,yorkshire1 and now in the ,manchester ,museum1 shows four large primary arms radiating from the base of an erect stump #d feet in diameter4 ,each arm divides a short distance from its base into two1 and the smaller branches extend almost horizontally for several feet#efa4 ,an illustration published by ,martin in #ahjiefb shows a characteristic feature of ,stigmarian casts1 namely the presence of a smaller axis1 usually occupying an eccentric position inside the larger4 ,this represents the cast of the fairly broad parenchymatous pith which1 on decay1 left a space subsequently filled by sand or mud3 at a later stage the surrounding wood and cortex were removed and the cavity so formed was similarly filled4 ,a thin layer of coal formed by the carbonisation of some of the tissues frequently surrounds the medullary cast1 and ,steinhauer1 whose account of the genus is much fuller and more scientific than those of other earlier and many later writers1 recognised the true nature of this internal cast4 ,artis#efc regarded it as the remains of a young plant1 which he described as 8perforating its parent10 at length bursting it and assuming its place1 a gratuitously drastic interpretation4 ,in #ahchefd ,lindley and ,hutton figured a partially petrified specimen of ,stigmaria obtained by ,prestwich from ,carboniferous rock of ,shropshire4 ,this example showed a fairly broad cylinder of secondary wood penetrated by medullary rays4 ,the medullated stele consisted of a pith surrounded by a small amount of primary xylem and by a cylinder of secondary scalariform tracheae4 ,the preservation of the tissues abutting on the edge of the wood is usually very imperfect1 and the middle cortex of lacunar parenchyma has practically in every case eluded the action of mineralising agents2 the outer cortex1 on the other hand1 consists of more resistant elements and is frequently well preserved4 ,as in ,lepidodendron and ,sigillaria stems1 meristematic activity produced a broad band of secondary cortex2 and beyond this were attached to cushion-like pads the numerous appendages1 each supplied with a single vascular bundle which arose from the primary xylem and passed outwards through a medullary ray4 ,there is abundant evidence that the appendages were hollow1 a fact in striking accord with the aquatic and semi-aquatic habitat 7cf4 ,isoetes root1 fig4 #acc1 ,g74 ,illustration3 ,,fig4 #bjf4 ,cyperus papyrus4 ,piece of rhizome showing rootlet-scars4 ,nat4 size4 ,m4,s4 ,the piece of dried rhizome of ,cyperus papyrus shown in fig4 #bjf is an almost exact counterpart of ,stigmaria ficoides2 the wrinkled and shrivelled surface and the circular root-scars containing the remains of a vascular bundle are striking features in common and1 it may be added1 the two plants1 though very different in structure and in systematic position1 illustrate anatomical adaptations to a similar environment4 ,stigmaria ficoides ,brongniart#efe4 ,figs4 #bjd1 #bje1 #bjg1 #bjh4 #ahji4 ,phytolithus verrucosus1 ,martin1 ,petrifact4 ,derb4 ,pls4 ,,xi-,,xiv4 #ahah4 ,phytolithus verrucosus1 ,steinhauer1 ,trans4 ,phil4 ,soc4 ,america1 ,n4,s4 ,vol4 ,i4 p4 #bfh1 ,pl4 ,,iv4 #ahbj4 ,variolaria ficoides1 ,sternberg1 ,flora der ,vorwelt1 p4 #bb1 ,pl4 ,,xii4 #ahbb4 ,stigmaria ficoides1 ,brongniart1 ,mem4 ,mus4 d'hist4 nat4 ,paris1 ,pl4 ,,xii4 fig4 #g1 p4 #bbh4 #ahbe4 ,ficoidites verrucosus1 ,artis1 ,antediluvian ,phytology1 ,pl4 ,x4 #ahdj4 ,stigmaria anabathra1 ,corda1 ,flor4 der ,vorwelt1 ,pl4 ,,xiv4 ,the first figure of ,stigmaria is said to be by ,petver in #agjd2 ,volkmann published illustrations of this common fossil in #agbj and ,parkinson in #ahjdeff4 ,binney1 whose researches may be said to have inaugurated a new era in the investigation of fossil plants1 wrote in #ahdd3 8,probably no fossil plant has excited more discussion among botanists than the ,stigmaria4 ,it is the most common of the whole number of plants found in the ,coal-,measures1 but there has hitherto been the greatest uncertainty as to its real nature#efg40 ,this uncertainty still exists1 at least in the minds of some who know enough of the available data to realise that our knowledge is imperfect4 ,to pass to the questions of the affinity and nature of ,stigmaria3 ,brongniart#efh at first compared his genus with recent ,aroideae1 but he afterwards#efi spoke of it as probably the root of ,sigillaria4 ,other writers regarded ,stigmaria as a dicotyledonous plant comparable with ,cacti and succulent ,euphorbias4 ,for many years opinion was divided as to whether ,stigmaria represents an independent and complete plant or the underground system of ,sigillaria4 ,artis#egj1 ,lindley and ,hutton#ega1 as well as ,goldenberg#egb1 believed it to be a prostrate plant unconnected with any erect aerial stem4 ,goldenberg figured one of the slender rootlets terminating in an oval body described as a reproductive organ4 ,this seed-like impression is either some extraneous body or an abnormal development at the end of a rootlet4 ,in #ahdb ,logan drew attention to the almost complete monopolisation by ,stigmaria of the underclays1 the rock which as a general rule occurs below a seam of coal4 ,he wrote3 8,the grand distinguishing feature of the underclays is the peculiar character of the vegetable organic remains2 they are always of one kind 7,stigmaria ficoides7 and are so diffused throughout every part of the bed1 that by their uniform effect alone the clay is readily recognised by the eye of the miner#egc40 ,this fact1 which has played a very conspicuous part in the perennial discussions on the origin of coal1 led to the almost general recognition of the underclays as surface-soils of the ,coal period forests4 ,the next step was the discovery of ,stigmaria in the ,coal-,measures of ,lancashire and in the ,carboniferous rocks of ,cape ,breton1 ,nova ,scotia1 forming the basal branches of erect stems identified by ,binney#egd1 ,bowman#ege and ,richard ,brown#egf as undoubted ,sigillariae4 ,in one case ,brown found what he considered to be convincing evidence of the continuity between ,stigmaria and ,lepidodendron4 ,in #ahdb ,hawkshaw#egg described certain fossil trees1 the largest of which had a circumference at the base of #ae ft41 discovered1 in the course of excavations for a railway in ,lancashire1 in soft shale at right angles to the bedding4 ,the surface features were not sufficiently clear to enable him to decide with certainty between ,sigillaria and ,lepidodendron1 but while inclining to the former1 it is interesting to note that the occurrence of numerous ,lepidostrobi near the root led him to recognise the possibility of a connexion between the ,stigmarian roots and ,lepidodendron stems4 ,in #ahdf ,binney gave an account of similar trees found at ,dukinfield near ,manchester3 he spoke of one stem as unquestionably a ,sigillaria with vertical ribs1 furrows1 and scars1 about #ae inches high and #d ft4 #aj inches in circumference4 ,he expressed his conviction that 8,sigillaria was a plant of an aquatic nature#egh40 ,similar descriptions of rooted stems in the ,coal-,measures of ,nova ,scotia were published by ,brown in #ahde1 #ahdf and #ahdi2 in the last paper he figured a specimen1 which has become famous1 showing a ,syringodendron stem terminating in branching ,stigmarian 7or possibly ,stigmariopsis7 roots bearing on the lower surface a series of what he called conical tap roots#egi4 ,a similar specimen discovered in ,central ,france nearly fifty years later demonstrated the accuracy of ,brown's description4 ,despite these discoveries the root-like nature of ,stigmaria was not universally accepted4 ,it was1 however1 generally agreed that ,stigmaria formed the roots of ,sigillaria2 it was1 moreover1 held by some that ,lepidodendron stems also possessed this type of root1 an opinion based on ,brown's record and on the occurrence of ,stigmaria in beds containing ,lepidodendron but no ,sigillaria stems1 as in the volcanic beds of ,arran and elsewhere1 and on observations of ,geinitz and others#ehj4 ,there is now general agreement that ,lepidodendron and ,sigillaria had the same type of 8root10 though the connexion of ,stigmaria with the former was not so readily admitted1 and indeed the evidence in support of it is still very meagre4 ,goeppert and other authors were unable to believe that the numerous species of ,sigillaria possessed roots of so uniform a type1 but ,goeppert1 by his recognition of several varieties of ,stigmaria1 supplied a partial answer to this objection4 ,messrs ,mellor and ,leslie#eha have described and figured some large casts of roots exposed in ,permo-,carboniferous rocks in the bed of the ,vaal river at ,vereeniging 7,transvaal7 which exhibit certain features suggesting comparison with ,stigmaria4 ,some of these reach a length of #dj-ej feet and1 when complete1 were probably not less than #ajj feet long3 in some of them the centre of the cast from which forked arms spread almost horizontally shows a depression in the form of a cross indicating a regular dichotomous branching like that of ,stigmaria4 ,the authors incline to the belief that the roots belong to ,noeggerathiopsis and not to a lycopodiaceous plant1 though ,lepidodendroid stems are abundant in the sandstone a few feet higher in the series4 ,despite the absence of any ,stigmarian scars on the surface of the fossil it is probable that these fine specimens are the rhizomes of some lycopodiaceous plant1 possibly ,bothrodendron1 which is not uncommon in the ,vereeniging beds4 ,admitting that ,stigmaria is part of ,sigillaria1 the next question is1 is ,stigmaria a root in the ordinary sense1 the underground system formed on germination of the spore and of equal age with the shoot1 or did it bear a different relation to the ,sigillarian stems8 ,to this question different answers would still be given4 ,goeppert#ehb discussed evidence in favour of the view that aerial ,sigillarian shoots were produced as vegetative buds on pre-existing ,stigmarian axes1 like young moss plants on a protonema4 ,at a later date ,renault#ehc developed a similar view as regards ,sigillaria2 but we may pass on to consider the more recent and complete observations of ,grand',eury#ehd and ,solms-,laubach#ehe4 ,the recognition of two distinct types of ,stigmariae in the ,coal-,measures of ,central ,france led ,grand',eury#ehf to institute a new genus1 ,stigmariopsis4 ,this type1 which is characterised by a difference in habit as well as by other distinguishing features1 is represented by such specimens as those figured by ,goldenberg as ,stigmaria abbreviata1 bearing lenticular scars spirally disposed on a cortical surface characterised by irregular longitudinal wrinklings4 ,stigmariopsis has frequently been found in direct continuity with ,sigillarian stems of the ,leiodermarian-,clathrarian type1 spreading obliquely downwards in the form of rapidly narrowing arms clothed with slender and usually simple appendages2 and from the under surface of these arms short conical outgrowths are given off4 ,it is probable1 as ,solms-,laubach believes1 that ,stigmariopsis was represented also by long horizontally creeping rhizomes#ehg of uniform breadth from which ribless ,sigillarian aerial shoots arose as bud-like outgrowths4 ,grand',eury1 the author of the genus1 confined the term to the shorter and more rapidly tapered organs spreading from the base of erect stems2 the horizontal rhizomes of all ,sigillarian stems he refers to ,stigmaria4 ,the pith-casts of ,sigillariopsis may be recognised by their long vertical ridges and grooves1 a feature readily understood by reference to the stem structure4 ,the ,stigmariopsis rhizomes though rare in ,england have been recognised by ,dr ,kidston#ehh in the ,middle ,coal-,measures of ,yorkshire2 he has figured a pith-cast very like that illustrated in ,solms-,laubach's ,memoir as ,stigmariopsis anglica4 ,the surface-features of a ,stigmariopsis pith-cast are clearly shown on a specimen from ,st tienne in the ,williamson collection#ehi4 ,sidenote3 ,,stigmariopsis ,the most complete account of ,grand',eury's views in regard to the anchoring and absorbing organs of ,sigillaria is given in his monograph on the ,coal-field of ,gard#eij1 ,st tienne1 and these are clearly stated also by ,solms-,laubach#eia who confirms the conclusions of the ,french author as to the manner of development of the aerial shoots4 ,grand',eury believes that both ,stigmaria and ,stigmariopsis are rhizomes and not true roots4 ,the surface-features of ,stigmaria have already been described4 ,this type ,grand',eury speaks of as characterised by the uniform diameter and considerable horizontal elongation of the bifurcated axes2 he thinks they grew both as floating rhizomes and on the ground3 they may frequently be traced for a considerable distance without showing any signs of connexion with aerial shoots1 but occasionally they have been seen in organic union with ,sigillarian stems4 ,he believes that these rhizomes were produced as the result of germination under water of the spores of ,sigillaria or ,lepidodendron and developed as long and branched aquatic rhizomes capable of independent existence4 ,under certain conditions1 as he thinks in shallower water1 the rhizomes produced bulb-like outgrowths which grew into erect stems having the surface-features of ,sigillaria4 ,this method of origin is practically the same as that described by ,goeppert in #ahfe4 ,the vascular medullated cylinder of these erect branches was in direct continuity with that of the ,stigmarian rhizomes4 ,illustration3 ,,fig4 #bjg4 ,an early stage in the development of ,sigillaria4 ,a4 ,surface-features enlarged4 7,after ,grand',eury47 ,illustration3 ,,fig4 #bjh4 ,later stage in the development of ,sigillaria2 ,syringodendron with ,stigmariopsis4 7,after ,grand',eury47 ,the next stage is that in which the undifferentiated bulb becomes swollen at the base and develops four primary roots 7fig4 #bjg ,b1 ,c7 which grow obliquely downwards and produce numerous rootlets4 ,meanwhile the parent rhizome gradually decays1 finally setting free the aerial stems which are now provided with spreading and forked roots 7fig4 #bjh7 such as we are familiar with in ,english specimens as ,stigmaria ficoides1 but which in the ,french specimens show the features of ,stigmariopsis4 ,at this later stage conical outgrowths are formed from the under surface of the ,stigmariopsis arranged in a more or less regular series surrounding the centre of the forked and spreading roots 7fig4 #bji74 ,these conical and positively geotropic organs were long ago described by ,richard ,brown as tap-roots4 ,grand',eury's conclusions are briefly as follows3 ,sigillaria1 and we may add ,lepidodendron1 had no true roots and in this respect are comparable with ,psilotum 7fig4 #aah73 the organs which are described by ,grand',eury as roots are correctly so named in a physiological sense1 but morphologically they do not strictly conform1 either in origin or in the arrangement of their appendages1 to true roots4 ,the question as to whether they are entitled to the designation root is one which it is needless and indeed futile to discuss in detail2 it would be conceding too much to a formal academic standpoint to refrain from applying to them the term root1 as that best describes their share in the life of the ,sigillarian stems4 ,the horizontal ,stigmarian axes are rhizomes in the ordinary sense of the term and from these were developed ,sigillarian shoots1 characterised in the lower portions by large parichnos strands4 ,from the base of the young bulbous shoots roots were formed3 these roots being1 in the ,french specimens1 of the ,stigmariopsis type4 ,illustration3 ,,fig4 #bji4 ,stigmariopsis and 8tap-roots40 7,after ,grand',eury47 ,these conclusions require some modification when applied to ,british representatives of the arborescent ,lycopodiales4 ,the long spreading and dichotomously branched root-like organs attached to the base of ,sigillarian and ,lepidodendron stems are true examples of ,stigmaria ficoides or other species4 ,stigmariopsis occurs but rarely4 ,this marked difference between ,french and ,english specimens may be explained if we adopt the opinion of ,solms-,laubach1 who believes that the true ,stigmaria represents both the parent rhizome and the later-formed roots of the ,rhytidolepis ,sigillarian species and of ,lepidodendron1 the ,stigmariopsis form having the corresponding relation to the ,leiodermarian-,clathrarian species4 ,the opinion expressed by ,williamson#eib in #ahib that ,grand',eury's hypothesis 8appears to be identical with the vague and speculative guesses that were prevalent among us in the early years of the present nineteenth century0 illustrates the strength of conviction based on ,english specimens as to the root-nature of ,stigmaria4 ,there is undoubtedly considerable confusion1 which can be cleared up only by further research1 as to the precise relation between ,stigmaria and ,stigmariopsis on the one hand and the different types of ,sigillariae on the other4 ,the main contention1 and this is the most important point1 of ,renault1 ,grand',eury and ,solms-,laubach as to the manner of formation of the aerial shoots from rhizomes and the subsequent production of forked roots and their ultimate separation from the parent rhizome is1 as ,i believe1 correct4 ,williamson held that ,stigmaria must be regarded as a true root2 he found no evidence to support the view that the large rooted stem discovered by ,hawshaw1 ,binney1 and others had been originally produced from aquatic rhizomes4 ,it must1 however1 be remembered that ,grand',eury's opinion is based on evidence afforded by the exceptionally well displayed ,sigillarian forests of ,st tienne1 on a scale such as ,english strata have not as yet afforded4 ,moreover1 the absence of any parent-rhizome in association with the rooted stumps described by ,williamson and by others is not a serious argument against their rhizome origin4 ,the specimen represented in fig4 #bji1 which was examined in situ by ,solms-,laubach and ,grand',eury1 shows a ,sigillarian stem in the ,syringodendron condition bearing rows of paired parichnos scars2 from the base forked and rapidly tapering arms radiate through the surrounding rock and1 as shown by other specimens1 these bear numerous appendages like those of the ,english ,stigmarias4 ,the surface-features of the arms are those of ,stigmariopsis and the centre of each1 as seen on the broken face1 is occupied by a pith-cast characterised by parallel longitudinal ridges resembling those on the medullary casts of ,calamites4 ,it is noteworthy that the petrified rhizome originally described by ,renault as ,stigmaria flexuosa1 and afterwards identified by him as the subterranean system of ,sigillaria ,brardi1 possesses a vascular cylinder composed of primary xylem strands of crescentic transverse section lining the pith2 a cast of the pith1 after the removal by decay of its delicate parenchymatous tissue1 would exhibit the surface-features of ,stigmariopsis4 ,stigmaria flexuosa no doubt represents a true ,stigmariopsis rhizome4 ,on the other hand1 as ,williamson has shown1 the inner surface of the wood of ,stigmaria ficoides consists of a reticulum of xylem with meshes of medullary-ray tissue2 a cast of such a surface presents a very different appearance from that of ,stigmariopsis4 ,returning to fig4 #bji3 from the lower surface of the ,stigmariopsis arms numerous conical outgrowths1 reaching a length of several centimetres1 project vertically downwards2 these also possess ,stigmariopsis pith-casts and are identical with the 8tap-roots0 of ,richard ,brown4 ,the stump seen in fig4 #bji shows the characteristic hollow base of the erect stem3 this is the region which1 it is believed1 represents the position of the ,stigmarian rhizome from which the aerial shoot was developed4 ,although no remains of the parent rhizome were found1 traces of the rootlets which probably belonged to it were found in the neighbourhood4 ,the absence of the actual rhizome is1 however1 not surprising as it would not persist after its aerial ,sigillarian branches had attained independence by the development of their own dichotomously branched absorbing and holdfast organs4 ,the ,stigmarian axes of ,palaeozoic ,lycopods are compared by ,miss ,thomas#eic with the prop-roots of certain recent flowering plants which grow in tropical tidal swamps2 their roots grow downwards from the stem at an angle of #ej-fj before spreading out horizontally4 ,this author also makes some interesting suggestions in regard to the evidence afforded by anatomical structure as to the habitat of ,sigillaria and ,lepidodendron4 ,anatomy4 ,the more important anatomical features of ,stigmaria must be dealt with briefly4 ,williamson's monograph1 published in #ahhgeid1 is considerably in advance of the work of that of any of the numerous writers who had previously dealt with the subject4 ,the diagrammatic transverse section reproduced in fig4 #baj1 ,h1 illustrates the general arrangement of the tissues4 ,the medullated stele was described by ,williamson as consisting entirely of centrifugally developed secondary xylem and distinguished1 therefore1 from the stele of a ,lepidodendron or ,sigillaria by the absence of a centripetally produced primary xylem zone4 ,the secondary xylem tracheae are characterised by scalariform pits on both radial and tangential walls and1 as shown in a figure given by ,solms-,laubach#eie1 the spaces between the transverse bars are bridged across by fine threads1 as in the tracheae of ,lepidodendron4 ,one of the largest specimens of a petrified ,stigmaria which ,i have seen is one lent to me by ,mr ,lomax from the ,coal-,measures of ,halifax in which the flattened transverse section measures #ah cm4 #ce cm41 the cylinder of wood being #aa cm4 #g mm4 in diameter4 ,in ,french examples of ,stigmaria or ,stigmariopsis it has been demonstrated by ,renault#eif that primary xylem strands occur very like those in the stem of some species of ,sigillariae 7see p4 #bai74 ,if a well-preserved section of an ,english ,stigmaria is examined it will be seen that the edge of the secondary wood consists of a few narrower elements which do not exhibit the radial seriation characteristic of secondary elements4 ,a type of ,stigmaria characterised by centripetal primary wood has been described by ,weiss#eig and referred by him to ,bothrodendron mundum2 the main results of his observations are stated in the account of ,bothrodendron on a subsequent page4 ,this discovery is of considerable interest not only as rendering our knowledge of ,bothrodendron remarkably complete but as confirmatory of ,renault's account of ,french ,stigmarian axes in which centripetal primary wood is well developed between the secondary xylem and the centre of the stele4 ,the ,stigmarian axis of ,bothrodendron was originally figured by ,williamson as ,lepidodendron mundum#eih4 ,the chief difference between ,weiss's specimen and those described by ,renault#eii as the ,stigmarian axes of ,sigillaria ,brardi1 is that in the ,english plant the centripetal wood forms a cylinder of uniform breadth instead of a band with a crenulated inner margin as figured by ,renault4 ,sidenote3 ,,stigmaria ,illustration3 ,,fig4 #baj4 ,stigmaria4 ,a4 ,transverse section of vascular bundle of rootlet and part of outer cortex4 t1 tracheae4 7,after ,f4 ,e4 ,weiss47 ,b1 ,c4 ,vascular bundle of rootlet2 in ,c a series of small tracheae are shown extending from the protoxylem4 ,d4 ,rootlets from the outer cortex of ,e4 ,e4 ,part of a large ,stigmaria3 ,st1 stele2 s1 intruded rootlet4 ,f4 ,vascular bundle and tracheae passing obliquely towards the outer cortex1 c4 ,g4 ,outer cortex of ,stigmaria4 ,h4 ,diagrammatic section of ,stigmaria3 p1 phelloderm2 r1 rootlets4 ,an interesting agreement between the ,french and ,english specimens is the occurrence in the cortex of groups of reticulate elements3 in ,weiss's section these are short and wide and occur in the middle cortex2 in ,renault's plant they are more fusiform and occur in the secondary cortical tissue4 ,these elements appear to have been arranged as an interlacing network in the middle cortex and were in close connexion with the rootlet-bundles1 comparable1 as ,weiss points out1 with the transfusion tracheids accompanying ,lepidodendron leaf-traces4 ,it is probable that these short and wide tracheal elements served for water-storage and thus afford another indication of the xerophilous character of the ,carboniferous ,lycopods1 a feature possibly connected with a salt-marsh habitat4 ,the presence of conspicuous medullary rays gives the secondary xylem of ,stigmaria the appearance of being divided into several more or less distinct groups 7fig4 #baj1 ,e1 ,st74 ,in tangential longitudinal section the xylem assumes the form of a broad reticulum with lenticular meshes filled with medullary-ray tissue through which strands of xylem are cut across in a transverse direction as they pass outwards from the inner edge of the wood to supply the rootlets4 ,in addition to these broader or primary medullary rays1 there were numerous secondary rays composed of narrow plates of parenchymatous cells one or several elements in depth4 ,as ,williamson pointed out1 the medullary-ray tissue consists in part of radially elongated tracheal elements with spiral or scalariform thickening bands like those described in the same position in ,lepidodendron stems4 ,our knowledge of the minute structure of the tissues abutting on the secondary xylem is far from complete4 ,the xylem is succeeded by a zone of delicate cells which was the seat of meristematic activity4 ,it is noteworthy that in a section figured by ,williamson#fjj there is the same disparity in size between the outermost elements of the xylem and the adjacent cells of the meristematic zone as in ,lepidodendron stems4 ,beyond this region an imperfectly preserved lacunar tissue occurs like that which ,i have called the secretory zone in ,lepidodendron stems2 but information as to the structure of this part of ,stigmaria is much more incomplete than in the case of the aerial shoots4 ,the middle cortex was of the same lacunar type as in the stems1 and the fact that it is never well preserved in large ,stigmarian axes suggests that it may have been even more richly supplied than in the aerial stems with an aerating system of spaces4 ,the outer cortex1 consisting in young examples of large-celled parenchyma1 became at an early stage of growth the seat of cambial activity which resulted in the production of radially placed series of secondary elements 7fig4 #baj1 ,h1 p74 ,the outer and older elements of this secondary cortex are more tangentially stretched than the inner cells1 a necessary result of the position of the phellogen on the internal edge of the tissue and of the increasing girth of the axis4 ,in comparatively young ,stigmarian axes the outer cortex already possesses a band of secondary radially disposed cells characterised by the greater tangential extension of the more external elements2 usually this tissue terminates abruptly on the inner edge and the line of separation no doubt marks the position of the phellogen4 ,occasionally some delicate secondary elements are preserved internal to the phellogen1 and these in young specimens form a narrow cylinder composed in part of radially elongated cells showing signs of recent tangential divisions4 ,in its earlier stage of activity the phellogen seems to form a greater amount of secondary tissue on the outside1 but this is clearly not of the nature of cork1 the tissue which occupies a corresponding position in recent plants4 ,the primary cortex shows no signs of shrinkage or collapse as would be the case were it cut off from the vascular system by a zone of impermeable cork4 ,fig4 #baj1 ,g1 represents a piece of the external tissue of a specimen in which the slightly flattened xylem cylinder measures #ad #a cm42 the inner cortex has disappeared and fragments only of the middle cortex are preserved4 ,the outer cortex1 with an average breadth of #b mm41 consists superficially of primary parenchyma with a somewhat uneven surface and with a rootlet attached here and there2 a short distance below the surface is a band of conspicuous cells1 b1 characterised by dark contents suggesting very imperfectly preserved fungal hyphae1 but the nature of the substance filling the cells cannot be made out with certainty4 ,it is1 however1 interesting to find that this dark band constitutes an obvious feature 7fig4 #baj ,h1 b72 its position is comparable with that of the dark-walled cells in the outer cortex of rootlets4 ,a short distance internal to this dark band tangentially elongated cells form the outermost elements of the secondary cortex2 these become gradually narrower towards the interior and pass into radial series of smaller cells of uniform size1 as seen on the inner edge of fig4 #baj1 ,g4 ,at the inner boundary of this tissue1 just below the region shown at the bottom of the drawing1 was situated the phellogen4 ,such traces of tissue as occur on the inner side of the line where splitting has usually occurred1 consist of thinner elements with recently formed tangential walls and probably represent an early stage in the development of phelloderm4 ,a much older section is shown in part in fig4 #baj1 ,e4 ,the secondary xylem cylinder1 ,st1 is shown in the lower part of the section2 beyond this is a band of secondary tissue which reaches in some places a breadth of #f cm4 ,the greater part of this tissue consists of phelloderm of very uniform structure made up of radial series of cells3 this is interrupted in most parts of the section by a gap crowded with intruded rootlets 7a portion of this is enlarged in fig4 #baj1 ,d74 ,beyond this gap the secondary tissue consists of radial series of cells characterised by the considerable tangential elongation of many of the elements1 precisely like the tissue figured by ,williamson4 ,in all probability the gap represents a line of weakness due to the phellogen1 and if this is the case it is clear that in an old ,stigmaria the phelloderm exceeded in amount the tissue formed external to the phellogen4 ,the secondary tissue on the inner side of the phellogen is characterised by numerous irregular concentric lines superficially resembling rings of growth in the wood of a ,conifer3 these are1 however1 not the result of any periodic change in external conditions1 but are apparently due to crushing of the tissue and are possibly1 to some extent1 the result of the presence of secretory strands like those in the phelloderm of ,lepidodendron4 ,the surface of this older rhizome retains patches of primary tissue1 and an occasional rootlet1 as at r1 fig4 #baj1 ,e1 is seen in connexion with the cortex2 the cortex has been vertically fissured as the result of secondary growth and presents an appearance like that shown in ,lepidodendron ,wnschianum and ,l4 ,veltheimianum 7figs4 #aha1 ,a1 and #ahf1 ,a74 ,the form in which a ,stigmarian rootlet is usually preserved is shown in fig4 #baj1 ,d2 the single vascular bundle strand with its endarch protoxylem 7fig4 #baj1 ,b1 px7 is enclosed by a ring of inner cortical parenchyma 7fig4 #baj1 ,f1 c72 the cells in immediate contact with the xylem having usually disappeared4 ,beyond the middle cortical space a second cylinder of parenchyma represents the outer cortex 7,f1 c7 in which a layer of dark-walled cells 7b1 fig4 #baj1 ,f7 may be compared with the hypodermal band in the main ,stigmarian axis 7,g1 b74 ,these ,stigmarian rootlets1 usually less than #a cm4 in diameter1 are the commonest objects in sections of the calcareous nodules from ,english coal-seams4 ,a good example of their abundance is shown in fig4 #baj1 ,d and ,e2 here they have invaded the space formed by the splitting of the secondary cortical tissues along the line of the phellogen and a few are seen here and there in the deeper layers of the phelloderm 7s1 fig4 #baj1 ,e74 ,not infrequently the close contact of these ubiquitous rootlets with the tissues of the plant which they have invaded leads to confusion between invader and invaded4 ,partially decayed tissues lying1 probably1 under water were penetrated by ,stigmarian rootlets in exactly the same way as the roots of recent plants bore through vegetable substances which happen to be in their path4 ,the rootlet bundles are in the first instance composed of the primary tracheae which line the inner edge of the secondary xylem2 these receive additions from the meristematic zone1 and thus1 when seen in the cortex outside the stelar region1 are found to consist in part of primary and in part of a fan-shaped group of secondary tracheae4 ,on the other hand1 the monarch bundle as it appears in a free rootlet is usually composed entirely of primary elements 7fig4 #baj1 ,a-,c1 ,f74 ,it has been shown by ,weiss#fja that in the ,stigmarian rhizome of what is probably ,lepidodendron fuliginosum1 the rootlet bundle is accompanied by a parichnos strand1 but this has not been detected in the ordinary ,stigmaria ficoides4 ,when free from the parent axis a rootlet usually consists of an outer cylinder of cortex enclosing a broad space in which remnants of lacunar tissue are sometimes seen4 ,the relation of the external features of a well-preserved ,stigmarian rootlet-scar to the internal structure of a petrified rootlet is very clearly seen on comparing such sections as those represented in fig4 #baj1 ,d1 with the form of the scar on a ,stigmarian cast4 ,a specimen figured by ,hooker#fjb in #ahdh affords a good illustration of the structure of a rootlet-base as seen in an unusually complete cast2 this correlation of anatomical and surface features is clearly described also by ,williamson#fjc and by ,solms-,laubach#fjd4 ,it is probable that even during life the rootlets were hollow for a part at least of their length as are the roots of ,isoetes 7fig4 #acc1 ,g74 ,an interesting discovery was made a few years ago which confirmed a statement by ,renault which ,williamson was unable to accept1 namely that the xylem bundle of a rootlet occasionally gives off a delicate tracheal strand at right angles to the long axis of a rootlet4 ,in some rootlets ,weiss#fje found obliquely running delicate strands of xylem1 surrounded by a layer of parenchymatous tissue1 in the space between the vascular bundle and the outer cortical cylinder4 ,it is clear that a few spiral tracheids are occasionally given off from the protoxylem of a rootlet bundle3 these follow an oblique course to the outer cortex1 where in some cases they have been traced into connexion with short and spirally marked cells resembling transfusion tracheae 7fig4 #baj1 ,a74 ,this arrangement may serve as a means of facilitating the passage of water absorbed by the superficial cells into the xylem strand4 ,it should be noticed that1 like roots of recent water-plants1 the rootlets of ,stigmaria had no root-hairs4 ,fig4 #baj1 ,f1 shows a transverse section of part of a rootlet in which the outer cortical cylinder1 c1 is connected1 as in the roots of ,isoetes1 with the sheath surrounding the vascular bundle4 ,a few obliquely cut tracheae are seen in this section traversing the connecting band of parenchyma t1 fig4 #baj1 ,a4 ,a point of biological interest in connexion with ,stigmaria rootlets is the occasional presence of hypertrophied cells1 the large size of which is due to the attacks of a fungus named by ,weiss#fjf ,urophlyctites stigmariae4 ,in addition to ,stigmaria ficoides1 which is by far the commonest form1 a few other species have been founded on external characters4 ,one of these is represented by ,stigmaria stellata1 ,goepp4#fjg1 characterised by the presence of radially disposed ridges and small tubercles surrounding each rootlet-scar4 ,kidston refers to ,goeppert's species as a ,lower ,carboniferous type4 ,we have no evidence as to the meaning of the stellate ridges and tubercles1 nor have we any reason to suppose that this form differed essentially in structure from ,stigmaria ficoides4 ,,chapter ,,xviii4 ,bothrodendreae4 ,bothrodendron4 ,figs4 #baa-baf4 ,although in many respects the genus ,bothrodendron agrees very closely in habit and in its anatomical features with ,lepidodendron1 there are reasons for referring it to a distinct family of ,palaeozoic ,lycopods4 ,as the following description shows1 the external features do not differ in any essential points from those of certain types of the genus ,sigillaria1 particularly such a species as ,s4 rimosa1 ,gold4#fjh1 which has recently been refigured and described by ,nathorst#fji from ,goldenberg's type-specimen in the ,stockholm ,museum4 ,the small size of the leaf-scars is1 however1 a characteristic feature of ,bothrodendron 7fig4 #bab1 ,f72 but a more important point is the fact that in a recently described#faj ,english example of a cone of ,bothrodendron 7fig4 #baf71 the sporangia are very like those of recent ,lycopods1 and differ from the radially elongated sporangia of ,lepidostrobus4 ,on the other hand1 a ,french cone described by ,zeiller#faa as ,lepidostrobus ,olryi1 which is probably a strobilus of ,bothrodendron1 has the radially elongated type of sporangium 7fig4 #bab1 ,e74 ,the comparative abundance of ,bothrodendron in ,lower ,carboniferous and ,devonian rocks points to the greater antiquity of this member of the ,lycopodiales as compared with ,lepidodendron4 ,the name ,bothrodendron was instituted by ,lindley and ,hutton#fab for impressions of stems from the ,english ,coal-,measures1 characterised by two opposite rows of large depressions like those shown in fig4 #baa and1 in one of the specimens1 by 8a considerable number of minute dots1 arranged in a quincuncial manner40 ,the minute dots were recognised as leaf-scars and the cup-like cavities were described as probably connected with the occurrence of large cones4 ,on very slender evidence this ,palaeozoic plant1 which was named ,bothrodendron punctatum1 was considered by these authors as probably a member of the ,coniferales4 ,the large stem from the ,coal-,measures in the neighbourhood of ,mons1 ,belgium1 shown in fig4 #baa1 affords a good illustration of ,bothrodendron in a partially decorticated condition1 exhibiting a row of depressions similar to those on the ,ulodendron form of ,lepidodendron ,veltheimianum 7fig4 #aeg71 but distinguished by the eccentric position of the scar at the bottom of each cup-shaped cavity3 in the ,belgian specimen1 which is partially decorticated and shows the leaf-traces as small dots1 the depressions have a diameter of #i cm4 ,it is believed by some authors that these ,ulodendron shoots of ,bothrodendron and ,lepidodendron owe their characteristic appearance to the pressure of large cones1 but1 as ,i have already stated1 there are reasons for preferring the view that these crater-like hollows are the scars of deciduous branches4 ,our knowledge of the strobili borne by ,bothrodendron stems is still meagre1 but we have no reason to assume the existence of any cones large enough to produce by the pressure of their bases such depressions as those shown in fig4 #baa4 ,in one species at least the strobili were borne terminally on slender shoots 7fig4 #bac74 ,the ,ulodendron condition has so far been recognised in one species only1 ,b4 punctatum4 ,in his catalogue of ,palaeozoic plants1 ,kidston#fac included ,bothrodendron punctatum as a synonym of ,sigillaria discophora ,knig1 a mistake which he afterwards rectified#fad3 the generic name ,bothrodendron was generally ignored by authors in the belief that the specimens described by ,lindley and ,hutton were not generically distinct from the fossils originally figured by ,rhode as ,ulodendron4 ,it was ,prof4 ,zeiller who first demonstrated that the ,english authors were justified in their choice of a new designation for stems with large depressions in association with minute leaf-scars4 ,in #ahei ,haughton#fae proposed a new family name ,cyclostigmaceae for some ,upper ,devonian plants from ,county ,kilkenny1 ,ireland3 he described three species of his new genus ,cyclostigma1 ,cyclostigma kiltorkense1 ,c4 minutum1 and ,c4 ,griffithsi2 these are now generally recognised as a single species of ,bothrodendron1 though1 as ,nathorst suggests1 the ,irish plant should perhaps be separated as a sub-genus ,bothrodendron 7,cyclostigma7 by reason of certain minor differences which distinguish it from other species of the genus4 ,illustration3 ,,fig4 #baa4 ,bothrodendron punctatum4 ,part of a specimen from near ,mons 7,hainaut71 in the ,brussels ,museum4 7,reduced47 ,another generic name1 ,rhytidodendron1 was instituted by ,boulay in #ahgf for stems characterised by a finely wrinkled bark and small spirally disposed leaf-scars4 ,a short description of this type1 which occurs in the ,middle and ,lower ,coal-,measures1 may serve to illustrate the external features of the commonest ,british example of the genus4 a4 ,bothrodendron minutifolium 7,boulay47 ,figs4 #bab1 ,a1 ,c1 ,d2 #bac4 #ahge4 ,lycopodium carbonaceum 7,lycopodites carbonaceus71 ,feistmantel1 ,palaeontographica ,,xxxiii41 ,pl4 ,,xxx4 figs4 #a1 #b2 p4 #ahc4 #ahgf4 ,rhytidodendron minutifolium1 ,boulay1 ,terr4 ,houill4 ,nord ,france1 p4 #ci1 ,pl4 ,,iii4 fig4 #a4 #ahhf4 ,bothrodendron minutifolium1 ,zeiller1 ,bull4 ,soc4 ,gol4 ,france iii ,,xiv4 p4 #agf1 ,pl4 ,,ix4 figs4 #a1 #b4 #ahhh4 ,lepidostrobus ,olryi1 ,zeiller1 ,flor4 ,valenciennes1 p4 #ejb1 ,pl4 ,,lxxvii4 fig4 #a4 #ahhi4 ,bothrodendron minutifolium1 ,kidston1 ,trans4 ,r4 ,soc4 ,edinburgh1 ,vol4 ,,xxxv4 ,pt4 ii4 #ahic4 ,sigillaria 7,bothrodendron7 minutifolia1 ,weiss and ,sterzel1 ,k4 ,preuss4 ,geol4 ,landesanstalt1 ,heft #b1 p4 #di1 ,pl4 ,i4 figs4 #c and #d2 ,pl4 ,,ii4 figs4 #h and #i4 #aijd4 ,bothrodendron minutifolium1 ,zalessky1 ,mm4 ,com4 ,gol4 ,russie1 ,pl4 ,,vi4 fig4 #f4 ,illustration3 ,,fig4 #bab4 ,bothrodendron4 ,a4 ,bothrodendron minutifolium1 var4 rotundata ,weiss4 ,after ,weiss and ,sterzel4 ,b4 ,b4 punctatum4 ,after ,zeiller4 ,c4 ,b4 minutifolium4 ,after ,weiss and ,sterzel4 ,d4 ,b4 minutifolium4 ,after ,zeiller4 ,e4 ,lepidostrobus ,olryi4 ,after ,zeiller4 ,f4 ,bothrodendron punctatum4 ,after ,zeiller4 ,g1 ,h4 ,b4 kiltorkense4 ,g1 after ,nathorst2 ,h1 after ,weiss and ,sterzel4 ,in habit a plant of ,bothrodendron recalls ,lepidodendron and recent species of ,lycopodium2 the slender dichotomously branched twigs bearing numerous leaves 7fig4 #bab1 ,d71 have been mistaken for shoots of ,lycopodium1 and fragments of branches might well be identified as impressions of ,mosses4 ,the leaf-scars on the smaller shoots occur on elongated cushions 7fig4 #bab1 ,c1 ,d7 with a transversely wrinkled surface2 on the older branches the leaf-scars are separated by fairly large areas of bark characterised by sinuous transverse grooves and narrow ridges bearing numerous small pits1 as shown on an enlarged scale in fig4 #bab1 ,a4 ,the original surface-features are shown on the left of the drawing1 and a slightly deeper level in the cortex is represented on the right-hand side4 ,the absence of leaf-cushions on the older shoots is probably the result of secondary thickening1 which also alters the size and shape of the leaf-scars4 ,each scar has three pits on its surface1 as in ,lepidodendron2 a central leaf-trace scar and lateral parichnos scars4 ,the circular pit above the leaf-scars1 which occurs in most species1 marks the position of the ligule4 ,the relation of the short leaves1 #e mm4 long1 to the leaf-cushions is shown in fig4 #bab1 ,d4 ,the absence of leaves1 except in impressions of slender twigs1 may be interpreted as an indication that they were shed at an early stage and did not persist many years4 ,the leaf-cushions of the smaller shoots of ,bothrodendron minutifolium closely resemble those figured by ,weiss on a ,devonian plant1 ,lepidodendron ,losseni#faf4 ,one of the few examples so far discovered of a ,bothrodendron cone is shown in fig4 #bac2 this specimen1 at least #aj cm4 long1 was found by ,mr ,hemingway in the ,middle ,coal-,measures of ,yorkshire and described by ,dr ,kidston4 ,numerous sporophylls are attached at right angles to the axis1 the surface of which is protected by their upturned distal portions2 the arrangement of the parts appears to be the same as in ,lepidostrobus4 ,a specimen figured by ,zeiller as ,lepidostrobus ,olryi1 which ,kidston is probably correct in identifying with ,bothrodendron minutifolium1 shows that each sporophyll carries a horizontally elongated sporangium 7fig4 #bab1 ,e74 b4 ,bothrodendron punctatum ,lindley and ,hutton#fag4 ,figs4 #baa1 #bab ,b1 ,f4 ,this species1 which is less abundant than ,b4 minutifolium1 in ,british ,coal-,measures1 has been described by several authors as ,ulodendron on account of the occurrence of large depressions1 like those shown in fig4 #baa1 on certain branches of the plant4 ,at the suggestion of ,dr ,kidston1 ,prof4 ,zeiller#fah figured an ,english specimen of this species1 presented to the ,paris ,museum by ,mr ,hutton1 in which the leaf-scars are preserved on the bark of a stem with ,ulodendron scars4 ,the surface of the bark is characterised by numerous small pits and discontinuous vertical lines in contrast to the transverse lines of ,b4 minutifolium 7cf4 fig4 #bab1 ,a and ,f74 ,the leaf-scars on the smaller shoots may have a diameter of only #jc-je mm41 while on the larger branches they reach a breadth of #a mm4 ,the ligule-pit may be in contact with the upper edge 7fig4 #bab1 ,f7 of the leaf-scar or separated from it by a short distance4 ,illustration3 ,,fig4 #bac4 ,bothrodendron minutifolium ,cone4 ,from a specimen in ,dr ,kidston's ,collection4 7,slightly reduced4 ,kidston 7#jb7 ,pl4 ,,lix47 c4 ,bothrodendron kiltorkense 7,haughton74 ,fig4 #bab1 ,g1 ,h4 #ahei4 ,cyclostigma kiltorkense1 ,haughton1 ,journ4 ,r4 ,soc4 ,dublin1 ,vol4 ,,ii4 p4 #dah1 ,pls4 ,,xiv4-,,xvii4 ,c4 minutum1 ,haughton1 ,journ4 ,r4 ,soc4 ,dublin1 ,vol4 ,,ii4 p4 #dah1 ,pls4 ,,xiv4-,,xvii4 ,c4 ,griffithsi1 ,haughton1 ,journ4 ,r4 ,soc4 ,dublin1 ,vol4 ,,ii4 p4 #dah1 ,pls4 ,,xiv4-,,xvii4 #ahgj4 ,lepidodendron ,veltheimianum1 ,heer 7ex parte71 ,k4 ,svensk4 ,vet4 ,akad4 ,handl4 ,vol4 ,,ix4 ,pl4 ,,ix4 figs4 #b-d4 ,cyclostigma kiltorkense1 ibid4 ,pl4 ,,xi4 figs4 #a-e4 ,calamites radiatus 7ex parte71 ibid4 ,pl4 ,,iii4 fig4 #b;a3 ,pl4 ,,ix4 fig4 #b;b4 ,stigmaria ficoides minuta1 ibid4 ,pl4 ,,ix4 fig4 #b;c4 ,knorria imbricata1 ibid4 ,pl4 ,x4 fig4 #d4 #ahhi4 ,bothrodendron kiltorkense1 ,kidston1 ,ann4 ,mag4 ,nat4 ,hist4 ,,vi41 ,vol4 ,,iv4 p4 #ff4 #ahid4 ,bothrodendron kiltorkense1 ,nathorst1 ,k4 ,svensk4 ,vet4 ,akad4 ,handl4 ,vol4 ,,xxvi4 ,no4 #d1 p4 #fe1 ,pls4 ,,xiv4 ,,xv4 #aijb4 ,bothrodendron 7,cyclostigma7 kiltorkense1 ibid4 ,vol4 ,,xxxvi4 ,no4 #c1 p4 #ca1 ,pls4 ,x4-,,xiv4 ,the specimens from the ,upper ,devonian rocks of ,co4 ,kilkenny on which ,haughton founded this and two other species may be regarded as representing one specific type4 ,he described the circular leaf-scars as arranged in alternating whorls4 ,in habit the ,irish species agrees with ,bothrodendron minutifolium1 but the leaf-scars are more elliptical 7fig4 #bab1 ,h7 and the ligule-pit is usually absent4 ,the leaf-scar shown in fig4 ,h is #ab mm4 broad and #ad mm4 in height4 ,the large collection obtained during the visit of a ,swedish expedition to ,bear ,island in #ahih under the leadership of ,dr ,nathorst has materially increased our knowledge of this ancient type4 ,the form of the leaf-scars varies according to the age of the branch and their disposition is far from constant even on the same specimen2 in some cases the scars are in fairly regular whorls 7fig4 #bab1 ,g2 an ,irish specimen7 while in others they are in regular spirals4 ,this irregularity of arrangement1 which is well illustrated by ,nathorst's figures of ,bear ,island and ,irish specimens1 finds its counterpart1 though in a less marked form1 in recent species of ,lycopodium1 e4g4 ,l4 ,selago4 ,partially decorticated stems may present a superficial resemblance to ,calamites1 the fissured bark simulating the ribs of a ,calamitean cast4 ,such stems1 as ,nathorst has pointed out1 were mistaken by ,heer for ,calamites radiatus4 ,the smaller branches are characterised by a smooth surface1 and older shoots resemble ,bothrodendron minutifolium in the presence of fine vertical lines4 ,the preservation of only one pit on the leaf-scars of many examples led authors to conclude that the species is peculiar in this respect1 but ,nathorst has shown that in more perfectly preserved specimens each leaf-scar bears three small dots4 ,a specimen from ,ireland in the ,british ,museum#fai illustrates the dichotomous branching and the longitudinal wrinkling of the bark2 the leaf-scars are #b mm4 broad and #be mm4 deep4 ,nathorst#fbj has described some examples in which the leaf-scars occur on the lower instead of on the upper end of the leaf-cushions2 these and other specimens with obscure surface-features he suggests may be underground axes1 comparable in habit with ,stigmaria though not identical as regards details4 ,it is pointed out that the absence or scarcity of ,stigmaria in the ,bear ,island beds renders it unlikely that ,bothrodendron bore typical ,stigmaria branches4 ,f4 ,e4 ,weiss#fba has recently described root-bearing organs possessing primary xylem identical with that of ,bothrodendron mundum2 while closely resembling ,stigmaria ficoides in certain anatomical characters1 they clearly represent a distinct type4 ,this discovery of a ,stigmaria-like axis almost certainly belonging to ,bothrodendron is consistent with ,nathorst's views on some of the ,bothrodendron impressions from ,bear ,island4 ,information as to the cones of this species is restricted to a description by ,schimper#fbb of a specimen in the ,dublin ,museum as ,lepidostrobus ,bailyanus2 this has sporophylls with a subtriangular base bearing several megaspores and terminating distally in a slender lamina #ab cm4 in length4 ,an example of a ,bothrodendron with more prominent leaf-cushions than those already mentioned is afforded by a species from ,bear ,island described by ,heer#fbc as ,lepidodendron ,wkianum and afterwards referred by ,nathorst#fbd to ,bothrodendron4 ,the same type is recorded also by ,schmalhausen#fbe from ,lower ,carboniferous or ,devonian strata of ,siberia4 ,certain ,scotch specimens from the ,calciferous ,sandstone1 which ,kidston#fbf referred to ,heer's species1 are regarded by ,nathorst and1 in part at least1 by ,weiss#fbg and ,sterzel as representing a distinct species which these authors designate ,bothrodendron ,kidstoni#fbh4 ,without attempting the hopeless task of discriminating between the various ,carboniferous and ,devonian specimens described under the names ,cyclostigma or ,bothrodendron1 reference may be made to the following records as illustrating the wide distribution of the genus4 ,schmalhausen#fbi records ,cyclostigma kiltorkense from ,siberian rocks assigned to the ,ursa stage 7,devonian or ,lower ,carboniferous74 ,the fossil described by ,dawson#fcj from the ,devonian of ,gasp as ,cyclostigma densifolium probably represents a badly preserved example of ,bothrodendron3 ,weiss's species ,cyclostigma hercynium#fca from ,lower ,devonian rocks of the ,hartz district may be identical with ,bothrodendron kiltorkense4 ,the supposed identity of the latter species with ,dechenia ,roemeriana ,goepp41 as described by ,potoni#fcb1 appears to require confirmation#fcc1 but if this author is correct the connexion demonstrates the continuity of ,bothrodendron shoots and ,stigmaria-like subterranean organs4 ,the specimens described from ,south ,africa1 from strata which may be correlated with the ,upper or possibly with the ,lower ,carboniferous series of ,europe1 as ,bothrodendron ,leslei#fcd in all probability represents a species closely allied to the ,irish and ,bear ,island type4 ,bothrodendron ,leslei named after ,mr ,leslie whose discoveries in the ,carboniferous ,sandstone of ,vereeniging 7,transvaal7 have added considerably to our knowledge of the ,south ,african ,palaeozoic types1 is represented by imperfectly preserved casts characterised by more or less circular scars displaying the same irregularity of arrangement as in ,bothrodendron kiltorkense4 ,the leaf-scars appear to have only one small pit1 but this may not be an original feature4 ,the identification of this plant as ,bothrodendron receives support from the discovery of rather more satisfactory specimens at ,witteberg sent to me for examination by ,dr ,schwarz#fce4 ,these fossils bear a striking resemblance to ,b4 kiltorkense4 ,cydostigma australe#fcf ,feist4 described from the ,lower ,carboniferous rocks of ,new ,south ,wales1 though too imperfectly preserved to refer with confidence to ,b4 kiltorkense1 is no doubt a closely allied type4 ,illustration3 ,,fig4 #bad4 ,bothrodendron ,leslei ,seward4 b4 ,natural size4 a1 c4 ,slightly enlarged4 ,illustration3 ,,fig4 #bae4 ,bothrodendron mundum 7,will474 ,a1 ,b4 ,from a specimen 7,no4 #bf7 in the ,cambridge ,botany ,school4 ,c4 ,british ,museum1 ,williamson ,collection4 7,no4 #daf b47 ,d1 ,e4 ,from a section in ,dr ,kidston's ,collection4 ,reference was made in ,volume ,i4 7p4 #acc7 to the so-called paper coal of ,carboniferous age from ,central ,russia1 which consists of masses of thin strips of cuticle of ,bothrodendron stems4 ,the figures published by ,zeiller#fcg show that the plant possessed an epidermis consisting of polygonal cells interrupted by spirally disposed gaps marking the position of leaves2 the gaps measure #je-ae mm4 in breadth and agree1 therefore1 with the size of the leaf-scars of the smaller forms of ,bothrodendron4 ,the specimens from the ,russian mines were first figured by ,trautschold and ,auerbach#fch as ,lepidodendron tenerrimum and afterwards referred by ,zeiller to ,bothrodendron punctatum#fci4 ,nathorst#fdj1 however1 states that an examination of the ,russian material leads him to retain the name originally proposed2 he records the same type from ,upper ,devonian rocks of ,spitzbergen4 ,the chief interest of these ,russian specimens is their manner of preservation1 which ,renault has described as the result of bacterial action2 he claims to have recognised the actual bacteria associated with the cuticular membranes#fda4 ,anatomy of vegetative shoots of ,bothrodendron4 ,in #ahhi ,williamson#fdb described several specimens of petrified shoots from the ,coal-,measures of ,halifax which he named ,lepidodendron mundum3 these are now known to be branches of a ,bothrodendron4 ,the discovery was made by ,mr ,lomax#fdc who found specimens showing the external characters of ,bothrodendron and the anatomical characters of ,lepidodendron mundum4 ,in some of the smaller twigs1 the stele consists of a solid core of xylem with external protoxylem2 but in the majority of specimens the centre of the xylem is replaced by parenchymatous tissue1 either as a small axial strand or1 as in the specimen shown in fig4 #bae1 ,d1 a wide pith1 the elements of which are arranged in regular vertical series4 ,a diagrammatic section of a small axis is represented in fig4 #bae1 ,a3 this branch1 #b mm4 in diameter1 is composed of a broad outer cortex consisting exclusively of primary tissue the outer cells of which are smaller and have thicker walls than the more internal elements4 ,the leaf-traces1 lt1 are accompanied by a strand of delicate tissue1 the parichnos4 ,the stele is almost solid2 the tissues in contact with the xylem have not been preserved but the inner cortex is represented by a few layers of small parenchymatous cells1 c4 ,the larger section shown in fig4 #bae1 ,d1 was cut from a specimen from ,dulesgate of which the smooth surface exhibits the characteristic leaf-scars of ,bothrodendron4 ,the section measures #c cm4 in its longest diameter and the stele has a breadth of #c mm4 ,the outer cortex has a smooth surface and is composed of rather thick-walled cells succeeded by a zone of secondary elements4 ,the middle cortex has disappeared and the space is partially occupied by ,stigmarian rootlets1 s1 and crushed patches of cortical tissue4 ,the position of a leaf-scar is seen at a2 this is more clearly shown in the enlarged drawing fig4 ,e4 ,in his account of ,lepidodendron mundum1 ,williamson#fdd described a section in which the primary wood is surrounded by a considerable thickness of secondary xylem2 a diagram of this is shown in fig4 #bae1 ,c4 ,an examination of the section led me to compare the structure of the outer cortical cells1 characterised by radial rows of tangentially elongated elements1 with the outer cortex of ,stigmaria4 ,it has recently been shown by ,weiss#fde that this and other similar sections present several points of agreement with ,stigmaria1 particularly with ,stigmaria ,brardi as described by ,renault4 ,at s in fig4 #bae1 ,c1 a vascular strand is seen passing through the outer cortex2 this is almost certainly the bundle of a rootlet3 in the sections described by ,weiss rootlets are shown in a similar position4 ,the chief anatomical features of the ,stigmaria-like organs of ,bothrodendron are3--the considerable development of secondary xylem1 the structure of the outer cortex1 which is practically identical with that of ,stigmaria ficoides1 and the association of groups of short transfusion tracheids with the bundles of the rootlets4 ,it is very probable that the absence of secondary xylem in the vegetative shoots of ,bothrodendron is merely an accident and not a real distinction between the aerial and subterranean branches of the plant2 a supposition rendered probable by the occurrence of secondary xylem in the axis of the cone described by ,watson4 ,as ,weiss points out1 there are certain differences between the true ,stigmaria and the corresponding organ of ,bothrodendron2 the secondary xylem in ,bothrodendron is not broken up by broad medullary rays as in the common ,stigmaria1 and in ,bothrodendron the occurrence of a ring of primary xylem is another peculiarity4 ,in the vegetative shoots of ,bothrodendron mundum the stele differs from those of ,lepidodendron in the narrower primary xylem ring and in the large size of the metaxylem tracheae2 from ,lepidodendron ,harcourtii and ,l4 fuliginosum the xylem is distinguished by its smoother outer face which consists of numerous narrow xylem elements4 ,illustration3 ,,fig4 #baf4 ,bothrostrobus4 l1 ligule4 7,after ,watson47 ,cones of ,bothrodendron 7,bothrostrobus#fdf74 ,the long and narrow cones referred to ,bothrodendron minutifolium from ,english and ,french ,coal-,measures are known only as impressions and it is not possible to say whether they were heterosporous or homosporous2 the drawing given by ,zeiller 7,fig4 #bab1 ,e7 shows that the sporangia were of the same form as those in ,lepidostrobus1 but we have no more exact information as to their morphology4 ,a recently published description of a petrified strobilus by ,mr ,watson affords a welcome addition to our knowledge4 ,there is little doubt that this cone was borne by a species of ,bothrodendron2 the evidence for this conclusion is supplied by the agreement of the anatomical characters of the stele with that of the vegetative shoots originally described by ,williamson as ,lepidodendron mundum and by the constant association of the cones and vegetative shoots4 ,in #ahhj ,williamson described a crushed cone containing both megaspores and microspores which he spoke of as 8a diminutive organism1 reminding us more of the dwarfed fruits of many living ,selaginellas than of the large ,lepidostrobi#fdg40 ,watson's specimens enable us to give a more complete account of this type4 ,the axis of the strobilus bears short sporophylls bent upwards into a distal limb with a conspicuous ligule in a deep pit beyond the shortly stalked sporangium4 ,the length of the strobilus is estimated at #aj mm42 the stele is of the same type as that of ,bothrodendron mundum1 but it differs from the specimens of the vegetative shoots so far found in having some secondary xylem4 ,as shown in the sketch reproduced in fig4 #baf each sporophyll is characterised by two tangentially placed grooves1 g1 on the lower face1 and by numerous transfusion tracheids1 tr1 above the vascular bundle1 vb1 immediately below the ligule1 l4 ,megasporangia and microsporangia occur on the same cone1 the megasporangia being on the lower sporophylls and containing a single tetrad of megaspores4 ,fig4 #bai1 ,e1 shows a radial longitudinal section of a microsporophyll bearing a sporangium on the adaxial side of the ligule1 l1 below which is the single vascular bundle and a group of short tracheids at t4 ,the sporangia closely resemble those of species of ,selaginella and ,lycopodium and1 as pointed out by ,watson#fdh1 they also recall the sporangia of the ,palaeozoic genus ,spencerites4 ,bothrostrobus is distinguished from ,spencerites by the presence of a ligule1 by the structure of the axis1 and by the different form of the sporophylls4 ,the occurrence of four spores only in the megasporangia is another character in which the extinct type resembles recent ,lycopods4 ,it is impossible to decide whether ,watson's cone represents a more or a less primitive type than ,lepidostrobus3 if we accept ,professor ,bower's views in regard to the evolution of vegetative organs by the sterilisation of sporogenous tissue1 we should probably place ,lepidostrobus lower in the series than ,bothrostrobus2 but the greater resemblance between the fertile and vegetative shoots of ,bothrodendron1 as compared with the more pronounced difference in the case of ,lepidodendron1 may be regarded as an argument in favour of recognising ,bothrodendron as the more primitive type4 ,another possible example of a ,bothrodendron cone has been described by ,nathorst from ,spitzbergen as ,lepidostrobus ,zeilleri#fdi2 this appears to consist of an axis bearing spirally disposed sporangia without any indication of sporophylls4 ,this strobilus may belong to ,bothrodendron tenerrimum4 ,pinakodendron4 ,the name ,pinakodendron#fej was instituted by the late ,prof4 ,weiss for a type of stem closely resembling ,bothrodendron but differing in the presence of a fine reticulation on the outer bark and in the form of the leaf-scars4 ,weiss's genus has been recognised by ,kidston in ,dumfriesshire but our knowledge of the plant is as yet based solely on a few small specimens4 ,omphalophloios 7a genus of uncertain systematic position74 ,figs4 #aic1 ,c1 #bag4 ,this generic name was instituted by ,white#fea for certain specimens of large stems originally described by ,lesquereux from the ,coal-,measures of ,north ,america as ,lepidodendron mammillatum and ,l4 cyclostigma4 ,the photograph reproduced in fig4 #aic1 ,c1 for which ,i am indebted to ,dr ,kidston#feb1 represents a specimen described by him from the ,upper ,coal-,measures of ,somerset as ,omphalophloios anglicus1 and identified with ,lepidodendron anglicum of ,sternberg4 ,the surface of the impression shown in fig4 #aic1 ,c1 is characterised by clearly defined rhomboidal areas or cushions 7fig4 #bag1 ,e7 like those of ,lepidodendron1 except in the absence of a median keel1 and similar to those on some forms of ,sigillaria ,brardi4 ,a short distance above the centre of each cushion is an oval or subcordate region bounded by a rim-like margin and containing a small oval scar1 presumably that of a vascular strand4 ,a triangular elevation which also shows a small pit 7,fig4 #bag1 ,e1 a7 occurs below the oval area4 ,the appearance of the surface-features varies considerably on different parts of a single specimen4 ,fig4 #bag1 ,d1 represents one of the numerous figures published by ,white in his detailed account of the ,american material4 ,each cushion bears a widely open ,v-shaped ridge1 which is described as a leaf-scar2 above this is an oval area 7#be mm4 #age mm471 the surface of which is bounded by a narrow rim4 ,within the rim is a smaller concave oval region with a small pit near its upper end4 ,illustration3 ,,fig4 #bag4 ,omphalophloios4 ,d4 ,after ,white4 ,e4 ,after ,kidston4 ,we cannot1 in the absence of petrified material1 arrive at any satisfactory conclusion as to the meaning of these surface-features4 ,white considers that ,omphalophloios is probably a rhizome of one of the arborescent ,lycopods1 but whether or not this is its true nature must be left for future discoveries4 ,the fact that the rootlet bundles of some ,stigmarian axes are accompanied by a parichnos strand1 as ,weiss has shown1 may prepare us for the discovery of surface-features on ,stigmariae not unlike those of ,omphalophloios4 7,fig4 #aic1 ,c47 ,a possible comparison may be suggested also with ,sigillaria ,brardi as figured by ,germar 7fig4 #aif1 ,a7 in which circular scars1 which may be the scars of rootlets1 occur below the leaf-base areas4 ,it is not impossible that in the surface-features of ,omphalophloios we have both leaf and rootlet scars represented4 ,general considerations4 ,the solid xylem core characteristic of the stele of some species of ,palaeozoic ,lycopodiales 7e4g4 ,lepidodendron esnostense and ,l4 rhodumnense7 may probably1 as ,tansley and ,chick#fec point out1 be regarded as the lineal descendant of a primitive axial strand of water-conducting elements4 ,in the course of evolution the centre of the tracheal column became partially converted into parenchymatous tissue1 as in ,lepidodendron vasculare4 ,the arrangement of the short cells in regular vertical series is reminiscent of an early stage in the development of tracheae3 instead of forming tubular conducting elements the central part of the stelar meristem acquired the short-celled form2 some of the cells became lignified as isodiametric storage tracheae while others persisted as thin-walled parenchyma4 ,the production of secondary xylem and an increase in the girth of the whole stem led to reduction in the amount of centripetally developed conducting channels4 ,some of these assumed a new rle and a shape in harmony with their functions4 ,a later stage is represented by a further encroachment of the central parenchyma on the cylinder of centripetal xylem1 as seen in ,lepidodendron ,harcourtii and other species4 ,the next stage is afforded by ribless species of ,sigillaria in which the primary xylem is broken up into separate conducting strands4 ,as ,kidston#fed reminds us1 it is in the geologically more recent species of ,sigillaria1 such as ,s4 ,brardi1 which persist into the ,permian era1 that this more extreme case of reduction occurs4 ,the older genus ,lepidodendron seems to have retained to the last the complete cylinder of primary xylem4 ,in the stele of ,stigmaria1 the rhizome of ,sigillaria and of ,lepidodendron1 reduction of the centripetal xylem has passed beyond the stage represented by the broken cylinder of the ribless ,sigillarias4 ,with the exception of the examples described by ,renault#fee and by ,weiss#fef1 ,stigmaria is characterised by little or no centripetal primary xylem4 ,it is1 however1 noteworthy that ,renault's ,stigmaria1 in which centripetal xylem forms a prominent feature1 is attributed to ,sigillaria ,brardi1 a species in which the vascular cylinder of the aerial stem illustrates a later and not an earlier phase in the replacement of centripetal by centrifugal wood4 ,it would seem1 as ,lady ,isabel ,browne#feg says1 that most ,stigmarian axes had reached a more advanced stage in specialisation than is shown in the stelar structure of the aerial shoots4 ,the relatively greater and probably the more precocious development of secondary xylem in ,stigmaria than in ,lepidodendron or ,sigillaria may have some significance in relation to the smaller amount of 8old wood#feh0 7in a phylogenetic sense7 in their steles4 ,as is pointed out in a later chapter1 recent researches into the anatomy of extinct members of the ,osmundaceae by ,kidston and ,gwynne-,vaughan have brought to light a striking parallelism in evolutionary sequence between the ,lepidodendreae and the ancestors of ,osmunda and ,todea1 the two surviving genera of one of the most ancient families of ferns4 ,there can be little doubt as to a very close relationship between ,sigillaria1 ,lepidodendron1 and ,bothrodendron4 ,sigillaria seems to have outlived ,lepidodendron and ,bothrodendron4 ,the two latter genera are recorded from ,upper ,devonian rocks in several localities1 ,bothrodendron being particularly abundant in the pre-,carboniferous floras of ,bear ,island and other parts of the world4 ,a remarkable stem described by ,dr ,white#fei as ,archaeosigillaria primaeva from ,upper ,devonian shales of ,new ,york is spoken of by him as 8one of the most highly developed representatives of a fairly distinct archaic group foreshadowing the later genera ,bothrodendron1 ,sigillaria1 ,lepidodendron and ,lepidophloios40 ,the type-specimen1 when first discovered1 consisted of an apparently unbranched stem reaching a length of #e metres4 ,from the swollen basal part ,stigmaria-like rootlets spread into the surrounding shale4 ,at a higher level the fissured bark shows indistinctly defined leaf-cushions which pass gradually upwards into cushions and scars arranged in closer order on regular vertical ribs4 ,the surface-features in this region are practically those of a ribbed ,sigillaria4 ,traced farther upwards the vertical ribs die out and cushions of the ,lepidodendroid form cover the surface of the bark4 ,the leaf-scars1 with a supraposed ligular pit and two vertically elongated parichnos-scars1 are said to bear a closer resemblance to those of ,sigillaria and ,bothrodendron than to the leaf-areas of ,lepidodendron4 ,nothing is known as to the anatomy of this stem1 nor have fertile shoots been discovered4 ,in the absence of more trustworthy evidence than is available conclusions of a phylogenetic nature must be accepted at their true value4 ,it is however legitimate to describe ,archaeosigillaria primaeva as one of the oldest examples of a lycopodiaceous plant which shows well-preserved external features1 and these are of exceptional interest as indicating a combination of generic characters4 ,this ,devonian type lends support to the view that ,lepidodendron and ,sigillaria are offshoots1 differing from one another in comparatively unimportant points1 from a common ancestral type4 ,the generally accepted statement that arborescent ,palaeozoic ,lycopodiales bore their sporangia on specially modified leaves 7sporophylls7 grouped in cones which were usually produced at the tip of slender branches1 has recently shared the fate of most rules4 ,prof4 ,bower in his ,origin of a ,land ,flora mentions a ,belgian specimen of ,pinakodendron musivum ,weiss from the ,westphalian series 7,middle ,coal-,measures71 to be described by ,dr ,kidston1 which bore its sporangia 8associated with the leaves of certain portions of the stem1 without any cone-formation4 ,the fertile and sterile portions are distinguished only by the presence or absence of sporangia#ffj40 ,lepidodendron and ,sigillaria can hardly be claimed as the direct ancestors of any existing type of ,lycopodiales1 but while exhibiting points of contact with ,lycopodium1 ,selaginella1 and ,psilotum they are perhaps more closely allied to ,isoetes4 ,lady ,isabel ,browne#ffa1 who has recently published an excellent summary of the evidence on the relation of the ,lepidodendreae to ,isoetes1 concludes her examination of the arguments by expressing the opinion that there is a strong probability of the correctness of the view that ,isoetes may be derived 8from the ,lepidodendraceae in the widest sense of the word40 ,this decision seems to me to accord best with the facts4 ,the further question as to the relation of these ,palaeozoic genera to plants higher in the scale must be reserved for fuller consideration in another volume4 ,an attempt will also be made to consider how far anatomical structure may be used as a guide to the conditions under which ,lepidodendron and ,sigillaria as well as other members of the ,permo-,carboniferous floras passed their lives4 ,the secondary xylem of ,lepidodendron and ,sigillaria affords a striking example of water-conducting tissue of homogeneous structure comparable with the wood of ,conifers rather than with that of ,angiosperms4 ,it was presumably formed1 for the most part1 under uniform climatic conditions3 the absence of rings of growth points to uninterrupted supply to evergreen shoots exposed to no alternation of activity and arrested growth4 ,attention has already been called to the absence of any tissue corresponding to secondary phloem4 ,even in young shoots of ,lepidodendron1 no tissue has been found external to the meristematic zone agreeing in the form of its elements with the channels through which the elaborated food is conveyed from the leaves of recent plants to the regions of cell-building4 ,that the #8secretory zone' may have served this purpose1 at least in young stems1 is not improbable4 ,on the other hand1 it is difficult to understand why older ,lepidodendron stems show no indication of additions to the secretory zone4 ,if this tissue served for the transport of proteids we should expect to find provision made for its constant renewal pari passu with the secondary growth of the xylem4 ,the conclusion seems to me inevitable that the supply of building-material was otherwise provided for than in recent vascular plants4 ,the physiological division of labour may have been less complete in the tissue-systems of the ,palaeozoic ,lycopods than in the more highly specialised organs of such an extinct genus as ,lyginodendron or than in recent plants4 ,our knowledge of the anatomical structure of many extinct types has already reached a stage when we should take greater heed of the modus operandi of the complex machinery revealed by a study of petrified stems4 ,from the known we proceed to interpret the unknown2 but there is a danger of neglecting the possibilities of evolution during the countless ages which separate the forests of the ,coal period from those of the present era4 ,we may easily allow preconceived ideas to warp our judgment in attempting to distribute the manifold activities which made up the life of a ,lepidodendron among the structural units of the plant-body4 ,,chapter ,,xix4 ,seed-bearing plants closely allied to members of the ,lycopodiales4 i4 ,lepidocarpon4 ,in #ahgg ,williamson#ffb published an account of some fossil seeds which he referred to ,brongniart's genus ,cardiocarpon#ffc1 a generic title for certain ,gymnospermous seeds4 ,some of these he identified1 on the authority of the author of the species1 with ,cardiocarpon anomalum ,carruthers#ffd4 ,several years later ,wild and ,lomax described a new type of strobilus from the ,lower ,coal-,measures of ,lancashire#ffe4 ,the result of this discovery and of the subsequent examination by ,scott of additional material1 was to establish the fact that the seeds described by ,williamson and generally accepted as ,gymnospermous1 are in reality sporangia belonging to a ,lycopodiaceous cone4 ,the seeds to which ,carruthers gave the name ,cardiocarpon anomalum are1 however1 distinct from those described under the same name by ,williamson and are those of a true ,gymnosperm4 ,for this seed-bearing strobilus ,scott#fff instituted the generic name ,lepidocarpon1 which he thus defined3 8,strobili1 with the characters of ,lepidostrobus1 but each megasporangium was inclosed1 when mature1 in an integument1 growing up from the superior face of the sporophyll-pedicel4 ,integument1 together with the lamina of the sporophyll1 completely enveloping the megasporangium1 or nucellus1 leaving only an elongated1 slit-like micropyle above4 ,a single functional megaspore or embryo-sac developed in each megasporangium1 occupying almost the whole of its cavity4 ,megaspore ultimately filled by the prothallus or endosperm4 ,sporophyll1 together with the integumented megasporangium and its contents1 detached entire from the axis of the strobilus1 the whole forming a closed1 seed-like1 reproductive body4 ,seed-like organ horizontally elongated1 in the direction of the sporophyll-pedicel1 to which the micropylar crevice is parallel40 ,lepidocarpon ,lomaxi1 ,scott4 ,fig4 #bah4 ,an immature cone of ,l4 ,lomaxi is practically identical with a ,lepidostrobus2 its sporangia are naked and only acquire their integuments at a later stage4 ,a mature strobilus has a diameter of at least #c cm4 and is about #d cm4 in length4 ,as in typical ,lepidostrobi1 the axis bears spirally disposed sporophylls1 and each sporophyll has a long narrow pedicel approximately at right angles to the cone axis with its distal end expanded into a broad and thick lamina 7fig4 #bah1 ,b74 ,at the distal end the pedicel has a thin marginal wing 7fig4 #bah1 ,c1 right-hand half7 continuous with the upturned protective lamina4 ,to the upper face of each sporophyll is attached along the whole length as far as the ligule1 a single large sporangium2 on each side of the base of the sporangium the sporophyll forms a supporting cushion4 ,the relation of the sporangium to the ligule1 l1 is shown in fig4 #bah1 ,b1 and in the tangential section1 ,c1 which illustrates the triangular form of the sporangium near its distal end4 ,in mature cones1 the sporangia assumed the form of seeds1 the change being due to the growth of an investing integument from the upper face of the sporophylls on each side of the sporangia4 ,fig4 #bah1 ,a1 illustrates the form of a sporangium as shown in tangential sections2 the vascular bundle is seen below the base of the sporangium and the gaps right and left of it probably mark the position of parichnos strands4 ,on each side of the sporangium1 b1 a fairly thick wall of tissue has grown up from the sporophyll1 forming an integument which overtops the apical ridge of the sporangium1 leaving a narrow micropyle in the form of a long crevice 7m1 fig4 #bah1 ,b74 ,at the proximal end of the sporangium the integument forms an enclosing wall2 at the distal end it abuts on and is continuous with the upturned end of the sporophyll4 ,it is clearly established by ,scott that the tissue which invests the sporangia is not the upturned margins of the sporophyll1 but a new formation fully entitled to the designation integument4 ,it is noteworthy that the integument is not developed until a late stage in the ontogeny of the strobilus2 it is not formed until after the production of the prothallus#ffg4 ,the diagrammatic sketch1 fig4 #bah1 ,b1 shows the relation of the integument to the sporophyll and sporangium1 the outline of the latter being indicated by a broken line4 ,the columnar wall of the sporangium 7fig4 #bah1 ,a1 b7 forms a closed beak within the micropylar crevice1 and in the interior of the sporangial cavity the slightly shrivelled membrane1 a1 represents the single megaspore2 traces of the aborted sister-cells of the megaspore are occasionally met with4 ,scott describes a specimen in which the megaspore is filled with tissue agreeing in appearance with the prothallus in a megaspore of ,isoetes or ,selaginella2 no undoubted archegonia or female organs have been discovered1 nor has any spore been found containing an embryo4 ,illustration3 ,,fig4 #bah4 ,lepidocarpon ,lomaxi1 ,scott4 ,a and ,c4 ,after ,scott4 ,b4 ,diagram of a single sporophyll3 m1 micropyle2 ,st1 stele4 ,the axis of ,l4 ,lomaxi has a medullated stele constructed on the same plan as that of some species of ,lepidodendron and ,lepidostrobus2 the vascular bundles supplying the sporophylls pass obliquely upwards and outwards from the stele1 ,st1 fig4 #bah1 ,b1 and bend slightly downward just before entering the pedicel of a sporophyll4 ,dr ,scott has also described a strobilus containing microsporangia partially enclosed by a rudimentary integument4 ,it is1 however1 of considerable interest to find a partial development in the case of a male flower of an integumentary outgrowth1 which it would seem could only be of real functional importance in the female shoot4 ,it is important to notice that specimens of a second species of ,lepidocarpon1 ,l4 ,wildianum1 are recorded from ,lower ,carboniferous beds of ,scotland1 a fact which points to a considerable antiquity for this seed-bearing ,lycopodiaceous type#ffh4 ,the most important question to consider in regard to ,lepidocarpon is--are we justified in applying to the integumented sporangia the term seed8 ,the megaspore was not set free as it is in recent ,pteridophytes1 such as ,azolla and other genera with which ,lepidocarpon may be compared2 it was on the other hand retained in the sporangium1 as may sometimes happen even in recent species of ,selaginella 7cf4 fig4 #aca1 ,d74 ,moreover1 the megaspore is characterised by a thin enclosing membrane in contrast to the thick coat of a spore which is destined to be shed4 ,the peculiar slit-like form of the micropyle is a distinguishing feature1 but this may be readily explained as a convenient form in the case of a radially elongated sporangium4 ,the absence of an embryo1 though a distinguishing feature of ,lepidocarpon1 cannot be held to be a serious obstacle to the use of the term seed2 in recent ,cycads the embryo1 as ,scott points out1 may not begin to develope until the seed has been shed4 ,it is possible that the seeds of ,lepidocarpon were not pollinated on the parent plant4 ,the lesson which this extinct type teaches1 is that certain ,lycopodiaceous plants of the ,palaeozoic era had reached an important stage in the evolution of a seed4 ,the morphological essentials of true seeds had been acquired2 but we do not know the biological conditions under which pollination and fertilisation were effected4 ,another point of considerable interest is the value of this discovery as an argument in favour of the view that some ,gymnosperms are derived from ,lycopod ancestors4 ,leaving the general question until later1 it may at any rate be stated that in ,lepidocarpon we have a demonstration of the fact that the ,lycopodiales were not always distinguished from ,gymnosperms by the absence of seeds4 ,there are certain features in ,lepidocarpon shared by the seeds of ,araucarieae#ffi which may well mean something more than mere parallel development in two distinct phyla of the plant-kingdom#fgj4 ii4 ,miadesmia4 ,in #ahid ,prof4 ,bertrand#fga published an account of certain fragments of petrified leaves and twigs of a small herbaceous ,lycopodiaceous plant1 under the name ,miadesmia membranacea1 which he discovered in ,english material in association with ,lepidodendron ,harcourtii4 ,subsequently ,scott recognised the megasporophylls of the same plant1 and microsporophylls have also been discovered4 ,the most complete account of ,miadesmia so far published we owe to ,dr ,benson#fgb1 whose description is based on specimens from several sources4 ,miadesmia membranacea1 ,bertrand4 ,fig4 #bai1 ,a-,d4 ,illustration3 ,,fig4 #bai4 ,a-,d ,miadesmia2 ,e ,bothrodendron4 ,a4 ,radial section of megasporophyll3 s1 sporangium2 m1 megaspore2 l1 ligule4 7,from a drawing kindly lent by ,mrs ,d4 ,h4 ,scott47 ,b1 ,c4 ,leaf with ligule4 7,from a section in ,dr ,kidston's ,collection47 ,d4 ,transverse section of sporophyll4 7,after ,scott47 ,e4 ,radial section of microsporophyll of ,bothrodendron4 7,from a section in the ,manchester ,museum2 ,hick ,collection ,r4 #djf47 ,the slender stem1 characterised by unequal dichotomy1 has a single protostele composed of scalariform tracheids with #c-f peripheral protoxylem groups4 ,a zone of delicate tissue surrounds the xylem2 this is described as phloem1 but it is not clear whether the designation is based on histological characters or primarily on its position4 ,the cortex consists of an inner lacunar tissue and an outer region limited by a small-celled superficial layer sharply contrasted with the underlying layers of larger cells4 ,the stem of ,miadesmia is not uncommon in sections of the ,lancashire calcareous nodules1 and may be recognised by the delicate crushed tissue of which it mainly consists and by large hypodermal parenchyma4 ,the spirally disposed leaves bear a conspicuous and relatively large ligule1 #c mm4 long1 in a deep pit 7fig4 #bai1 ,b and ,c7 roofed over by a few layers of tissue corresponding to the velum in ,isoetes 7cf4 fig4 #acc1 ,e1 v74 ,the fairly thick central region of the lamina is expanded laterally into thin wings1 which in the living state probably bore delicate hairs4 ,these delicate leaves1 apparently without stomata1 were attached to the stem at an acute angle1 and ,miss ,benson suggests that their form and arrangement may have enabled them to hold water by surface-tension4 ,as seen in fig4 #bai1 ,b1 ,c1 which represents part of a transverse section near the leaf-base1 the ligule is a very characteristic feature1 and the size of the single vein is in keeping with the almost filmy nature of the lamina4 ,in addition to the sections in ,british collections1 ,i have been enabled by the kindness of ,prof4 ,bertrand to see photomicrographs of the sections on which he founded the genus4 ,one of these sections1 transverse to the stem and leaves1 illustrates in a striking manner the relatively large size of the leaves and ligules in proportion to the delicate axis of the shoot4 ,the megasporangiate cone has an axis which agrees in its structure with that of the vegetative stem and bears several megasporophylls approximately at right-angles4 ,as in the foliage leaves1 the ligule is prominent and large1 and lies in a groove which contains also the megasporangium2 both ligule1 l1 and sporangium1 s1 as seen in the transverse section represented in fig4 #bai1 ,d1 are covered by an integument or velum which arises in the proximal part of the leaf and leaves a circular micropylar opening at the beak-like apex of the sporangium4 ,the circular micropyle is surrounded by numerous hairs borne on the integument and which presumably played the part of a feathery stigma4 ,a single megaspore with a thin membrane1 m1 abuts on the fairly strong sporangial wall1 s2 in some cases the sporangium and megaspore walls may be indistinguishable1 a feature suggesting comparison with seed-structure4 ,some megaspores have been found filled with a prothallus4 ,the longitudinal section shown in fig4 #bai1 ,a1 illustrates the characteristic horizontal position of the megasporophyll1 as also the relation of the ligule1 l1 to the sporophyll with its single vascular bundle1 and to the hairy integument1 which overarches both sporangium and ligule2 the line m shows the position of the megaspore-membrane1 detached from the sporangial wall on the upper side but in contact with it below4 ,the microsporophyll shown in #bai1 ,e1 was originally referred to ,miadesmia but has since been recognised by ,watson#fgc as that of a ,bothrostrobus4 ,miadesmia affords an example of a ,palaeozoic plant comparable with ,isoetes and ,selaginella2 it agrees also with ,lepidocarpon in possessing true seeds1 and with ,watson's ,bothrodendron cone in the shape of the sporangia1 which are more like those of ,selaginella than the radially elongated sporangia of ,lepidostrobus4 ,miadesmia agrees with ,selaginella1 e4g4 ,s4 spinosa1 in its stelar structure1 in the form of the sporangia1 and in the presence of a ligule4 ,it is distinguished by having only one instead of four megaspores in a sporangium1 in the possession of an integument which formed a close investment to the spore and served as a stigma 7comparable with the stigma-like integument of the male flower of ,welwitschia71 and in the shedding of the megasporophylls1 which have been aptly compared with winged seeds4 ,sidenote3 ,,lepidocarpon ,on the ground of their general anatomical features ,lepidocarpon and ,miadesmia are clearly entitled to be included among extinct representatives of the ,pteridophyta4 ,these plants had1 however1 crossed what it has been customary to regard as the boundary between ,pteridophytes and ,phanerogams3 they possessed megasporangia with the attributes of seeds4 ,it has been suggested by ,lester ,ward#fgd that ,pteridophytic seed-bearing plants shall be recognised as a distinct phylum for which he proposes the name ,pteridospermaphyta1 a designation implying exclusion from the ,spermatophyta as usually understood4 ,for seed-bearing ,lycopodiaceous genera he suggests the name ,lepidospermae4 ,as knowledge of the ,palaeozoic seed-plants increases revision of existing classifications and group names will become necessary1 but as yet we are hardly in a position to draw up a satisfactory scheme of grouping2 we know little of ,lepidocarpon as a whole and it would be premature to commit ourselves1 even provisionally1 to a classification which is based on such meagre evidence as we possess4 ,moreover the value to be attached to the seed-habit as a basis of classification can hardly be estimated until fuller information is obtained4 ,,chapter ,,xx4 ,,filicales4 ,this division of the ,pteridophyta includes both the true ferns 7,filicineae7 and the less familiar water-ferns or ,hydropterideae4 ,the almost complete absence of satisfactory evidence in regard to the geological history of the latter renders this group of secondary importance from a palaeobotanical standpoint1 but1 on the other hand1 we possess a wealth of material bearing on the past history and relative antiquity of the true ferns4 ,the study of extinct types has so far rendered no substantial help towards bridging the wide gap between the ,filicales and the lower plants4 ,as ,mr ,tansley#fge says in his admirable lectures on ,the ,evolution of the ,filicinean ,vascular ,system1 8,the biggest gap in the plant kingdom at the present time is undoubtedly that which separates the ,pteridophytes from the plants definitely below them in organisation1 and directly we try to step behind the ferns we tumble into this abyss40 ,resemblances long ago recognised between certain ferns and the cycads1 a section of the ,gymnosperms1 were regarded by a few botanists as indications of blood-relationship1 and the results of recent researches into the morphological characters of extinct ,palaeozoic types are generally held to confirm these surmises4 ,prof4 ,chodat#fgf of ,geneva has recently challenged the validity of the arguments on which the affinity of cycads and ferns has been accepted by the great majority of botanists4 ,whether or not his criticisms stand the test of unbiassed examination1 they must at least lead us to substitute a critical consideration of the facts for a mere repetition of conclusions which appeal to our imagination4 ,despite ,prof4 ,chodat's warning1 we may still quote with confidence a phrase used in another connexion--ferns 8are links in a chain and branches on the tree of life1 with their roots in a past inconceivably remote#fgg40 ,sidenote3 ,,pteridosperms ,transitional forms which are regarded as pointing to a common origin for ferns and cycads are known in abundance2 other types have also been discovered which lead some authors to go so far as to derive the whole of the seed-bearing plants from an ancestry the descendants of which are represented by existing ferns4 ,while hesitating to allow the ferns or fern-like plants the peculiar position of universal ancestors1 we must admit that there is no group of plants with a history of greater importance from an evolutionary standpoint than that with which we are now concerned4 ,there are1 however1 some difficulties to face in attempting to decipher the history of the ,filicineae as recorded in the earth's crust4 ,few fossil plants are so familiar as the well-preserved carbonaceous impressions of compound leaves on the shales of our ,coal-,measures1 which were referred by older authors to recent genera and species of ferns and accepted by later writers as undoubted examples of ,palaeozoic ferns4 ,the common belief in the dominance of ferns in ,palaeozoic floras is reflected in the novelist's description of the ,carboniferous period1 8when the forms of plants were few and often of the fern kind#fgh40 ,we now know that very many of these ,carboniferous leaves belonged to plants differing widely in morphological characters from the modern genera to which they exhibit so deceptive a resemblance4 ,these pseudo-ferns1 recently christened ,pteridosperms or seed-bearing fern-like plants1 are dealt with in a later chapter4 ,the discovery of this extinct group has added enormously to our knowledge of plant-evolution and at the same time has rendered much more difficult the task of unravelling the past history of the true ferns4 ,as soon as it was demonstrated that many familiar ,palaeozoic 8ferns0 are not ferns1 some authors went far towards concluding that however close might be the agreement between fossil and recent leaves suspicion of close relationship must be set aside4 ,like the earlier writers who described fossils as lusus naturae fashioned by devilish agency to deceive too credulous man1 the discovery of seed-bearing plants with the foliage of ferns threatened to disturb the mental balance of palaeobotanists4 ,the fact is1 we cannot in some cases determine from leaf-form alone whether or not a fossil is a true fern2 we may1 as ,professor ,bower#fgi suggests1 regard all fern-like fossils as ferns until they are proved to be ,pteridosperms1 or in a spirit of scientific scepticism1 we may at once admit that many ,palaeozoic fern-like leaves must await further evidence before their true position can be determined4 ,it is impossible1 as ,zeiller#fhj says1 in the present state of our knowledge to range fern-like ,palaeozoic plants in two groups1 one referred to ,filicineae and the other to the ,pteridosperms4 ,the following classification of the ,filicales is based on that adopted by ,prof4 ,engler in the latest edition of his ,syllabus#fha and on the results of ,bower's#fhb excellent work on the spore-bearing members of recent ferns4 ,the members of the ,filicales are characterised by the same well-marked physiological division of labour in their vegetative parts as are the ,lycopods2 the plant is the asexual generation 7sporophyte71 while the sexual generation 7gametophyte7 is small and inconspicuous1 either an independent green prothallus or a tissue more or less completely enclosed in the spore4 ,the large size of the leaves1 which in the young state are usually coiled like a crozier 7fig4 #bbj1 ,a71 is a striking characteristic of the ferns2 they are megaphyllous in contrast to the microphylly of the ,lycopods4 ,i4 ,leptosporangiate ,filicales4 ,in these homosporous and heterosporous plants the sporangia are developed from single epidermal cells4 ,illustration3 ,,fig4 #bbj4 ,young fronds of 7,a7 ,angiopteris evecta and 7,b7 ,cycas revoluta4 7,reduced47 7a7 ,eufilicineae4 ,the sporangia bear spores of one kind only2 the wall of a sporangium consists of one layer of cells4 ,in the great majority of cases the sporangia are characterised by the possession of a conspicuous row of thick-walled brown cells1 the annulus#fhc1 which serves as a mechanism for dehiscence and spore-dispersal4 ,the fertile leaves1 identical in form with the sterile1 or more or less sharply contrasted1 usually bear the sporangia on the under surface of the lamina in definite groups or sori1 and not on the upper surface or grouped in strobili as in the ,lycopodiales4 ,the stem is dorsiventral or radial in structure1 creeping or erect1 frequently clothed with chaffy scales 7ramenta7 and less often with multicellular hairs4 ,the sexual generation is represented by a small green prothallus which lives for a short period only and dies after nursing the fern-plant through its earliest stages4 7b7 ,hydropterideae4 ,heterosporous water-ferns differing considerably in habit from the true ferns4 ,each megasporangium contains a single megaspore and several microspores are produced in each microsporangium4 ,the gametophyte is represented by tissue more or less enclosed in the spore4 ,genera ,salvinia1 ,azolla1 ,marsilia1 ,regnellidium1 ,pilularia4 ,see ,chapter ,,xxvi4 7a7 ,eufilicineae4 ,the classification of the true ferns in common use is based almost exclusively on the structure of the sporangium1 the form and position of the sori1 and on the presence or absence of an indusium 7the tissue which in some ferns partially or completely covers each sorus74 ,in recent years there has been considerable activity in the investigation of fern anatomy with a view to elucidating the natural relationship between recent families or genera4 ,the results of these researches are on the whole consistent with the scheme and grouping adopted in the ,synopsis ,filicum of ,hooker and ,baker and in general harmony with the main conclusions arrived at by ,bower from an intensive study of the development of fern sporangia4 ,the following classification is based on that of ,bower who takes as a basis 7i7 the relative time of appearance of the sporangia in a single sorus1 7ii7 the structure of the sporangia and their orientation relative to the whole sorus1 7iii7 the productiveness of sporangia 7spore-output74 ,osmundaceae ,simplices 7,bower74 ,the sporangia are relatively ,schizaeaceae large and all the sporangia in a sorus have a ,gleicheniaceae simultaneous origin3 the annulus is oblique4 ,matonineae ,gradatae 7,bower74 ,sporangia arise in basipetal ,loxsomaceae succession on a more or less elongated receptacle ,hymenophyllaceae 7portion of the leaf lamina which projects as a ,cyatheaceae cushion or column on which the sporangia are ,dennstaedtiinae borne72 annulus oblique2 indusium1 if present1 in the form of a cup or flap of tissue arising from the base of the sorus4 ,mixtae 7,bower74 ,this division includes the ,polypodiaceae1 by far the largest family of ferns4 ,polypodiaceae ,the sporangia are characterised by their ,parkeriaceae relatively small size1 the presence of a slender stalk1 the absence of regular orientation or sequence in development1 and by the presence of a vertical annulus4 ,the ,dipteridinae include species with the characters ,dipteridinae of the ,mixtae1 and one species in which the sporangia develope simultaneously 7,simplices74 ,osmundaceae#fhd4 7,osmunda1 ,todea47 ,sporangia large and rather stouter than those of other ,leptosporangiate ferns1 borne in small groups 7filmy species of ,todea7 in linear and frequently confluent sori 7,todea barbara2 fig4 #bba1 ,d7 or clustered round the axis of modified fertile pinnae with much reduced lamina 7,osmunda74 ,the annulus is represented by a group of thicker-walled cells a short distance below the apex 7fig4 #bba1 ,c74 ,this family stands apart among the ferns2 in some respects1 e4g4 in the more robust sporangia occasionally forming synangia1 and in the presence of stipular wings1 it forms a transitional series between the ,leptosporangiate and ,eusporangiate ferns4 ,the only ,european species of ,osmunda1 ,o4 regalis1 is almost cosmopolitan in range2 other species occur in ,north and ,south ,america1 in the ,far ,east1 the ,malay ,peninsula1 and in other regions1 more especially in the temperate zones4 ,todea is represented by 7i7 the ,south ,african and ,australian species1 ,t4 barbara1 a fern with a stem1 which may reach a height of several feet1 thickly covered with adventitious roots and bearing large and somewhat leathery fronds2 7ii7 filmy species in ,new ,zealand1 ,new ,south ,wales1 ,new ,caledonia1 and elsewhere4 ,a plant of the small tree-fern ,todea ,wilkesiana 7,fiji1 ,samoa1 and other islands7 in the filmy-fern house at ,kew1 to which my attention was drawn by my friend ,mr ,a4 ,w4 ,hill1 has a slender stem with the characteristic leaf-scars exposed2 it presents a striking similarity to some of the fossil species of ,osmundaceae described in a later chapter4 ,illustration3 ,,fig4 #bba4 ,a4 ,osmunda cinnamomea 7after ,faull74 ,b4 ,todea barbara1 p1 phloem2 s1 sclerenchyma4 ,c4 ,osmunda regalis 7after ,luerssen74 ,d4 ,todea barbara 7 nat4 size74 ,schizaeaceae4 7,schizaea1 ,aneimia1 ,lygodium1 ,mohria47 ,sporangia borne singly and not in groups 7sori71 readily recognised by the complete transverse apical annulus usually one layer of cells deep1 but occasionally two layers in depth on the side opposite the line of dehiscence#fhe 7fig4 #bbd1 ,b74 ,schizaea 7fig4 #bbb7 with the exception of one species in ,north ,america 7,s4 pusilla7 is characteristic of ,northern ,india1 the ,malay region1 ,australia1 ,new ,caledonia1 ,s4 ,africa1 and elsewhere south of the ,equator4 ,aneimia 7figs4 #bbc1 #bbd1 ,a1 ,b71 characterised by the fertile segments with reduced lamina1 is chiefly ,american3 the monotypic genus ,mohria1 resembling in habit the ,polypodiaceous genus ,cheilanthes1 occurs in ,s4 ,africa and ,madagascar1 while species of ,lygodium are widely spread tropical ferns1 with one species in temperate ,north ,america4 ,this family has disappeared from ,europe4 ,illustration3 ,,fig4 #bbb4 ,schizaea elegans4 7,slightly reduced47 ,a few of the segments terminate in narrow fertile lobes4 ,illustration3 ,,fig4 #bbc4 ,aneimia rotundifolia4 7,from the ,royal ,gardens1 ,kew4 nat4 size47 ,gleicheniaceae ,gleichenia1 ,platyzoma 7 ,g4 microphylla74 ,sporangia form circular naked sori composed of a variable number of sporangia1 usually not more than ten and frequently fewer1 characterised by an obliquely horizontal and almost complete annulus 7fig4 #bbd1 ,i74 ,in some species of ,gleichenia 7sect4 ,eugleichenia7 the ultimate segments are very small and semicircular in form 7fig4 #bbf1 ,c71 in others 7sect4 ,mertensia#fhf7 the segments are linear 7fig4 #bbf1 ,d71 and in many species the fronds are distinguished by the regular dichotomous branching 7fig4 #bbe71 frequently showing an arrested rachis bud in the forks#fhg protected by modified pinnules 7fig4 #bbf1 ,d1 ,e74 ,in ,platyzoma the leaves are simple1 reaching a length of #bj-cj cm41 and bear small revolute oval segments4 ,illustration3 ,fig4 #bbd4 ,a4 ,aneimia flexuosa4 ,b4 ,a4 phyllitidis4 ,c4 ,hymenophyllum dilatatum4 ,d1 ,e1 ,f1 ,g4 ,matonia pectinata2 i1 indusium4 ,h4 ,thyrsopteris elegans4 ,i4 ,gleichenia circinata4 7,a1 ,b1 after ,prantl2 ,c1 ,g1 ,h1 ,i1 after ,bower47 ,illustration3 ,,fig4 #bbe4 ,gleichenia dicarpa4 7 nat4 size47 ,illustration3 ,,fig4 #bbf4 ,a1 ,b4 ,gleichenites ,rostafinskii1 ,raciborski4 ,c4 ,gleichenia dicarpa4 7,nat4 size47 ,d1 ,e4 ,gleichenia dichotoma4 7,reduced47 7,a1 ,b1 after ,raciborski2 ,c1 after ,hooker2 ,d1 ,e1 after ,goebel47 ,gleichenia is represented by several species in the tropics and extends to south temperate and ,antarctic latitudes4 ,the species ,g4 dichotoma 7 ,g4 linearis7 is one of the more successful tropical ferns1 while ,g4 moniliformis 7by some authors recognised as a distinct genus1 ,stromatopteris7 is peculiar to ,new ,caledonia4 ,the monotypic genus ,platyzoma is a xerophilous ,australian fern4 ,the ,gleicheniaceae are unrepresented in existing north temperate floras4 ,matonineae4 7,matonia47 ,the genus ,matonia1 placed in the ,cyatheaceae by ,sir ,william ,hooker and compared by other authors also with the ,gleicheniaceae1 is now included in a special family4 ,the sori are circular and consist of #e-aa large sporangia 7fig4 #bbd1 ,e1 ,g7 sessile on a central columnar receptacle which spreads out into an umbrella-like indusium 7,d1 i7 with its incurved margin tucked in below the ring of sporangia4 ,the indusium is detached when the sporangia are ripe4 ,the annulus is oblique and incomplete and often slightly sinuous2 it agrees in the main with that of ,gleichenia4 ,the species ,matonia pectinata is characterised by dichotomously branched fronds 7figs4 #bbg1 #bbh7 with long and slender petioles2 the pinnae bear linear pinnules with forked lateral veins and occasional lateral anastomoses 7fig4 #bbd1 ,f74 ,the only other living representative is ,m4 sarmentosa1 discovered by ,mr ,charles ,hose at ,niah1 ,sarawak#fhh3 this species has long pendulous leaves apparently very different from those of ,m4 pectinata1 but the branching of the frond may be regarded as a modification of a primitive form of dichotomy#fhi4 ,a small bud occurs in the angle between the forked linear segments and the rachis1 as in some species of ,gleichenia#fij4 ,matonia is confined to the ,malay region3 ,m4 pectinata grows in ,western ,borneo and in various localities in the ,malay peninsula1 while ,m4 sarmentosa1 has been found in one locality only2 the latter species has recently been transferred to a new genus ,phanerosorus1 but in view of the practical identity in anatomical structure and the close agreement as regards the sori of the two species there would seem to be no justification for this change of name#fia4 ,illustration3 ,,fig4 #bbg4 ,matonia pectinata4 7 nat4 size47 ,m4,s4 ,loxsomaceae4 ,the ,new ,zealand genus ,loxsoma has marginal sori with a cup-like indusium surrounding an elongated receptacle bearing pear-shaped sporangia provided with a complete oblique annulus4 ,the genus is chiefly interesting because of its isolated position2 it agrees with ,trichomanes 7,hymenophyllaceae7 in the structure of the sorus and with species of ,dicksonia and ,davallia in habit2 it shows some resemblance also to ,gleicheniaceae and ,schizaeaceae#fib4 ,a new type of fern described by ,christ#fic from ,costa ,rica as ,loxsomopsis costaricensis affords a striking instance of discontinuous distribution and emphasises the antiquity and generalised features of the family4 ,illustration3 ,,fig4 #bbh4 ,matonia pectinata4 ,from a photograph by ,mr ,tansley of a group of plants in a wood on ,gunong ,tundok1 ,mount ,ophir4 ,hymenophyllaceae4 7,hymenophyllum1 ,trichomanes47 ,the sporangia1 which are attached to a columnar receptacle or prolongation of a vein beyond the margin of the lamina1 are characterised by an obliquely transverse annulus 7fig4 #bbd1 ,c74 ,a cup-like indusium surrounds the lower portion of the receptacle which is two-lipped in ,trichomanes and entire in ,hymenophyllum 7fig4 #bgj1 ,c1 ,d74 ,these two filmy ferns have a wide distribution both in tropical and extra-tropical regions2 they are represented in the ,british ,isles by ,hymenophyllum tunbrigense1 ,h4 ,wilsoni1 and ,trichomanes radicans4 ,illustration3 ,,fig4 #bbi4 ,a4 ,thyrsopteris elegans4 ,b4 ,cyathea spinulosa4 ,c4 ,davallia concinna4 ,d4 ,dicksonia coniifolia4 ,e4 ,alsophila excelsa4 ,f1 ,g4 ,dicksonia culcita4 7,a1 after ,diels and ,kunze2 ,b1 ,d1 ,f1 ,g1 after ,hooker2 ,e1 after ,bower47 ,cyatheaceae4 7,cyathea1 ,hemitelia1 ,alsophila1 ,dicksonia1 ,thyrsopteris47 ,the sporangia occur in indusiate or naked sori and have an obliquely vertical and incomplete annulus 7fig4 #bbi1 ,e74 ,in the great majority of cases the fronds are large and highly compound1 but ,cyathea sinuata ,hook1 a rare ,ceylon species1 bears simple narrow linear leaves4 ,this family includes1 with few exceptions1 all the tree ferns#fid4 ,the sori of ,dicksonia are enclosed in a two-valved indusium 7fig4 #bbi1 ,f4 ,g72 in the species represented in fig4 #bcj the fertile segments1 which terminate in cup-like indusia1 are characterised by the absence of a lamina and closely resemble those of ,thyrsopteris 7fig4 #bbi1 ,a74 ,in ,cyathea the indusium has the form of a cup which is at first closed and afterwards opens at the apex 7fig4 #bbi1 ,b72 in ,hemitelia the indusium is much reduced and in ,alsophila the sori are naked4 ,thyrsopteris is characterised by the reduced fertile pinnules bearing stalked sori in deep cups 7fig4 #bbi1 ,a74 ,the appearance of this fern 8is very remarkable1 for the cup-shaped sori hang down from the fronds in masses1 looking just like masses of millet seed#fie40 ,the sporangia are described by ,bower#fif as large and of rather peculiar form4 ,as seen in fig4 #bbd1 ,h1 the annulus is continuous2 it forms a twisted loop of cells which vary in shape and in the thickness of the walls4 ,the ,cyatheaceae are for the most part tropical ferns with a wide geographical range1 usually in moist regions2 they are1 however1 able to flourish under widely different temperature conditions4 ,in ,tasmania1 as ,diels#fig points out1 tree ferns may occasionally be seen laden with snow1 and on the west coast of ,new ,zealand they overhang the edge of a glacier#fih4 ,the monotypic genus ,thyrsopteris is confined to ,juan ,fernandez4 ,the ,cyatheaceae no longer exist in ,europe4 ,illustration3 ,,fig4 #bcj4 ,dicksonia ,bertercana ,hook4 ,fertile and sterile pinnae4 7,nat4 size4 ,british ,museum ,herbarium47 ,dennstaedtiinae4 7,microlepia1 ,dennstaedtia47 ,this sub-tribe1 instituted by ,prantl1 has been revived by ,bower on the ground that the sori present features intermediate between those of ,cyatheaceae and the ,polypodiaceous genus ,davallia4 ,the sporangia have a slightly oblique annulus4 ,polypodiaceae4 ,this section of the ,leptosporangiate ferns1 including several sub-tribes1 comprises the great majority of recent genera4 ,the sporangia form naked or indusiate sori and have a vertical incomplete annulus4 ,in ,plagiogyria#fii the oblique annulus and soral features suggest comparison with the ,cyatheaceae4 ,a more intimate acquaintance with ,polypodiaceous ferns will undoubtedly demonstrate the existence of other generalised types#gjj4 ,from the point of view of the identification of fossil ferns it is important to bear in mind the very close resemblance presented by some ,polypodiaceous species1 e4g4 species of ,davallia 7fig4 #bbi1 ,c71 to ,cyatheaceous ferns 7cf4 fig4 #bbi1 ,d74 ,parkeriaceae4 7,ceratopteris47 ,the almost spherical and scattered sporangia are characterised by the peculiar form of the vertical annulus1 which is composed of numerous cells differing in their greater breadth and smaller depth from those of a typical annulus4 ,exannulate sporangia have been described1 while others occur showing different stages between a rudimentary and a complete ring4 ,the single species of ,ceratopteris1 ,c4 thalictroides1 is an annual aquatic fern widely spread in tropical countries#gja4 ,illustration3 ,,fig4 #bca4 ,a1 ,a4 ,dipteris quinquefurcata 7type-specimen in the ,kew ,herbarium74 ,b1 ,c1 ,e1 ,g4 ,d4 conjugata4 7,c1 nat4 size47 ,d4 ,polypodium quercifolium4 ,f4 ,dipteris ,wallichii4 7,d1 after ,luerssen47 ,dipteridinae4 7,dipteris47 ,the genus ,dipteris1 formerly included in the ,polypodiaceae1 has been assigned to a separate family partly on account of the slight obliquity of the vertical annulus 7fig4 #bca1 ,g7 and on other grounds#gjb4 ,the four species ,dipteris conjugata1 ,d4 ,wallichii1 ,d4 ,lobbiana 7 ,d4 bifurcata71 and ,d4 quinquefurcata 7fig4 #bca7 are characterised by a creeping rhizome bearing fronds reaching a length of #ej cm42 in ,d4 conjugata and ,d4 ,wallichii the lamina is divided by a median sinus into two symmetrical halves1 while in other species the leaf is dissected into narrow linear segments4 ,the main dichotomously branched ribs are connected by lateral branches and these by tertiary veins1 the delicate branches of which end freely within the square or polygonal areolae 7fig4 #bca1 ,a1 ,e74 ,the naked sori are composed of numerous sporangia and filamentous hairs3 while in some species the soral development conforms to that characteristic of the ,mixtae1 it has been shown that in one species1 ,d4 ,lobbiana 7 ,d4 bifurcata#gjc71 the sporangia develope simultaneously as in the ,simplices4 ,dipteris occurs in company with ,matonia on ,mt ,ophir and elsewhere in the ,malay peninsula2 it extends to the ,philippines1 ,samoa1 ,new ,caledonia1 ,china1 ,new ,guinea1 and the subtropical regions of ,northern ,india4 ,the impossibility of drawing a hard and fast line between the divisions adopted in any system of classification is well illustrated by the ferns4 ,in the main1 the three-fold grouping suggested by ,bower is probably consistent with the order of evolution of the true ferns4 ,the ,polypodiaceae1 which are now the dominant group1 are in all probability of comparatively recent origin1 while the ,gradatae and ,simplices represent smaller subdivisions with representatives in remote geological epochs4 ,the genera ,loxsoma1 ,matonia and ,dipteris afford examples of ferns exhibiting points of contact with more than one of ,bower's subdivisions3 they are generalised types which1 like many relics of the past1 are now characterised by a restricted geographical range4 ,sidenote3 ,,recent ,,ferns ,illustration3 ,,fig4 #bcb4 ,davallia aculeata4 7 nat4 size47 ,it is noteworthy that while certain vegetative features may in some cases be cited as family-characters1 such features are not usually of much value from a taxonomic point of view4 ,while the typical tree ferns are practically all members of the ,cyatheaceae1 a few members of other families1 e4g4 ,todea barbara 7,osmundaceae7 and the monotypic ,indian genus ,brainea 7,polypodiaceae71 form erect stems several feet in height2 but these differ in appearance from the ,palm-like type of the ,cyatheaceous tree ferns4 ,on the other hand1 the thin1 almost transparent1 leaf of ,hymenophyllum tunbridgense and other filmy ferns is a character shared by several species of ,todea1 ,asplenium resectum1 and ,danaea trichomanoides 7,marattiaceae72 the filmy habit is essentially a biological adaptation4 ,the form of frond represented by certain species of ,gleichenia1 characterised by a regular dichotomy of the axis and by the occurrence of arrested buds1 is on the whole a trustworthy character1 though ,davallia aculeata 7bearing spines on its rachis7 7fig4 #bcb7 and ,matonia sarmentosa have fronds with a similar mode of branching and also bear arrested radius-buds4 ,a limited acquaintance with ferns as a whole often leads us to regard a certain form of leaf as characteristic of a particular species1 but more extended enquiry usually exposes the fallacy of relying upon so capricious a feature4 ,the form of leaf illustrated by ,trichomanes reniforme is met with also in ,gymnogramme reniformis and is fairly closely matched by the leaf of ,scolopendrium nigripes4 ,the fronds of ,matonia pectinata 7figs4 #bbg1 #bbh7 bear a close resemblance to those of ,gleichenia ,cunninghami1 ,adiantum pedatum1 and ,cheiropteris palmatopedata#gjd4 ,the habit1 leaf-form1 and distribution of ,ferns4 ,the full accounts of the structure and life-history of the common ,male ,fern1 given by ,scott in his ,structural ,botany and by ,bower in the ,origin of a ,land ,flora1 render superfluous more than a brief reference to certain general considerations in so far as they may facilitate a study of fossil types4 ,in size ,ferns have a wide range3 at the one extreme we have the filmy fern ,trichomanes ,goebelianum#gje1 growing on tree stems in ,venezuela1 with leaves #be to #c mm4 in diameter1 and at the other the tree ferns with tall columnar stems reaching a height of #dj to #ej feet and terminating in a crown of fronds with a spread of several feet4 ,a common form of stem is represented by the subterranean or creeping rhizome covered with ramental scales or hairs3 the remains of old leaves may persist as ragged stumps1 or1 as in ,oleandra1 ,polypodium vulgare and several other species1 the leaf may be cut off by the formation of an absciss-layer#gjf leaving a clean-cut peg projecting from the stem4 ,as a rule the branches bear no relation to the leaves and are often given off from the lower part of a petiole1 but in a few cases1 e4g4 in the ,hymenophyllaceae1 it is noteworthy that true axillary branching is the rule#gjg4 ,in the typical tree-fern the surface resembles that of a ,cycadean trunk covered with persistent leaf-bases and a thick mass of roots4 ,among epiphytic ferns highly modified stems are occasionally met with1 as in the ,malayan species ,polypodium 7,lecanopteris7 carnosum and ,p4 sinuosum#gjh4 ,the leaves of ferns are among the most protean of all plant organs2 as ,darwin wrote1 8the variability of ferns passes all bounds#gji40 ,the highly compound tri- or quadripinnate leaves of such species as ,pteris aquilina1 ,davallia and other genera stand for the central type of fern frond2 others exhibit a well-marked dichotomy1 e4g4 ,lygodium1 ,gleichenia1 ,matonia1 etc41 a habit in all probability associated with the older rather than with the more modern products of fern evolution4 ,before attempting to determine specifically fossil fern fronds1 it is important to familiarise ourselves with the range of variability among existing species and more especially in leaves of the same plant4 ,a striking example of heteromorphy is illustrated in fig4 #bcc4 ,reinecke#gaj has figured a plant of ,asplenium multilineatum in which the segments of the compound fronds assume various forms4 ,in ,teratophyllum aculeatum var4 inermis ,mett41 a tropical climbing fern believed by ,karsten#gaa to be identical with ,acrostichum 7,lomariopsis7 sorbifolium1--an identification which ,goebel#gab questions1--the fronds which stand free of the stem supporting the climber differ considerably from the translucent and much more delicate filmy leaves pressed against the supporting tree4 ,from this fern alone ,fe is said to have created #ag distinct species4 ,in this1 as in many other cases1 differences in leaf-form are the expression of a physiological division of labour connected with an epiphytic existence4 ,some tropical species of ,polypodium 7sect4 ,drynaria71 e4g4 ,p4 quercifolium 7fig4 #bcd and fig4 #bca1 ,d71 produce two distinct types of leaf1 the large green fronds1 concerned with the assimilation of carbon and spore-production1 being in sharp contrast to the small slightly lobed brown leaves which act as stiff brackets 7fig4 #bcd1 ,m7 for collecting humus from which the roots absorb raw material4 ,similarly in ,platycerium the orbicular mantle-leaves differ widely from the long pendulous or erect fronds fashioned like the spreading antlers of an elk4 ,in ,hemitelia capensis1 a ,south ,african ,cyatheaceous species1 the basal pinnae assume the form of finely divided leaves identified by earlier collectors as those of a parasitic ,trichomanes 7fig4 #bce74 ,in a letter written by ,w4 ,h4 ,harvey in #ahcg accompanying the specimen shown in fig4 #bce1 he says1 8,apropos of ,hemitelia1 be it known abroad that supposed parasitical ,trichomanes 444 is not a parasite1 but a part of the frond of ,hemitelia40 ,the delicate reduced pinnae remain on the stem and form a cluster at the base of the fronds#gac4 ,illustration3 ,,fig4 #bcc4 ,polypodium ,billardieri ,br4 7 nat4 size47 ,middle ,island1 ,new ,zealand4 ,from specimens in the ,cambridge ,herbarium4 ,illustration3 ,,fig4 #bcd4 ,polypodium quercifolium4 7,much reduced3 ,m1 ,mantle-leaves47 ,in many species the sporophylls are distinguished from the sterile fronds by segments with little or no chlorophyllous tissue1 as in ,onoclea struthiopteris#gad in which1 each year1 the plant produces a funnel-shaped group of sterile leaves followed later in the season by a cluster of sporophylls2 or1 as in many other genera1 the fertile leaves are distinguished also by longer petioles and thus serve as more efficient agents of spore-dissemination4 ,in ,ceratopteris the narrow segments of the taller fertile leaves are in striking contrast to the broader pinnules of the submerged foliage leaves4 ,leaf-form is in many cases obviously the expression of environment2 the xerophilous fern ,jamesonia#gae from the treeless paramos of the ,andes#gaf is characterised by its minute leaflets with strong revolute margins and a thick felt of hairs on the lower surface2 in others1 xerophilous features take the form of a covering of overlapping scales 7,ceterach71 or a development of water-tissue as in the fleshy leaves of the ,himalayan fern ,drymoglossum carnosum4 ,in the ,bracken fern ,boodle#gag has shown how the fronds may be classed as shade and sun leaves2 the former are spreading and softer1 while the latter are relatively smaller and of harder texture 7fig4 #bcf1 a and b74 ,even in one leaf six feet high1 growing through a dense bush of gorse and bramble1 the lower part was found to have the features of a shade leaf1 while the uppermost exposed pinnae were xerophilous4 ,illustration3 ,,fig4 #bce4 ,hemitelia capensis ,r4 ,brown4 ,nat4 size4 a1 ,pinna of normal frond4 ,from a specimen in the ,british ,museum4 ,m4,s4 ,illustration3 ,,fig4 #bcf;a4 ,pteris aquilina4 ,part of leaf from greenhouse4 7 nat4 size47 ,after ,boodle4 ,sidenote3 ,,pteris ,the resemblance between some of the filmy ,hymenophyllaceae and thalloid ,liverworts#gah is worthy of mention as one of the many possible pitfalls to be avoided by the palaeobotanical student4 ,the long linear fronds of such genera as ,vittaria and ,monogramme might well be identified in a fossil state as the leaves of a grass-like ,monocotyledon1 or compared with the foliage of ,isoetes or ,pilularia4 ,the resemblance of some fern leaves with reticulate venation to those of ,dicotyledons has led astray experienced palaeobotanists2 it is not only the anastomosing venation in the leaves of several ferns that simulates dicotyledonous foliage1 but the compound leaves of many dicotyledons1 e4g4 ,paullinia thalictrifolia 7,sapindaceae7 and species of ,umbelliferae1 may easily be mistaken for fronds of ferns4 ,illustration3 ,,fig4 #bcf b4 ,pteris aquilina4 ,leaf from the same plant grown out of doors4 7 nat4 size47 ,after ,boodle4 ,sidenote3 ,,recent ,,ferns ,the dichotomously lobed lamina of some ,schizaeas1 e4g4 ,s4 dichotoma and ,s4 elegans 7fig4 #bbb71 bears a close resemblance to the leaves of ,baiera or ,ginkgo#gai4 ,the original description by ,kunze#gbj of the ,south ,african ,cycad ,stangeria paradoxa as a ,polypodiaceous fern illustrates the difficulty1 or indeed impossibility1 of distinguishing between a sterile simply pinnate fern frond and the foliage of some ,cycads4 ,the deeply divided segments of ,cycas ,micholitzii#gba simulate the dichotomously branched pinnae of ,lygodium dichotomum1 and the leaves of ,aneimia rotundifolia 7fig4 #bbc7 and other species are almost identical in form with the ,jurassic species ,otozamites ,beani1 a member of the ,cycadophyta4 ,there are certain facts in regard to the geographical distribution of ferns to which attention should be directed4 ,mr ,baker in his paper on fern distribution writes3 8,with the precision of an hygrometer1 an increase in the fern-vegetation marks the wooded humid regions#gbb40 ,if in a collection of fossil plants we find a preponderance of ferns we are tempted to assume the existence of such conditions as are favourable to the luxuriant development of ferns at the present day4 ,on the other hand1 we must bear in mind the wonderful plasticity of many recent species and the fact that xerophilous ferns are by no means unknown in present-day floras4 ,ferns are admirably adapted to rapid dispersal over comparatively wide areas4 ,bower#gbc estimates that in one season a ,male ,fern may produce about #e1jjj1jjj spores3 with this enormous spore-output are coupled a thoroughly efficient mechanism for scattering the germs and an unusual facility for wind-dispersal4 ,when ,treub#gbd visited the devastated and sterilised wreck of the ,island of ,krakatau in #ahhf1 three years after the volcanic outburst1 he found that twelve ferns had already established themselves2 the spores had probably been carried by the wind at least #be to #cj miles4 ,it is not surprising1 therefore1 to find that many ferns have an almost world-wide distribution2 and1 it may be added1 in view of their efficient means of dispersal1 wide range by no means implies great antiquity4 ,prof4 ,campbell#gbe has recently called attention to the significance of the wide distribution of ,hepaticae in its bearing on their antiquity2 the spores are incapable of retaining vitality for more than a short period1 and it is argued that a world-wide distribution can have been acquired only after an enormous lapse of time4 ,if we apply this reasoning to the ,osmundaceae among ferns1 it may be legitimate to assume that their short-lived green spores render them much less efficient colonisers than the great majority of ferns2 if this is granted1 the wide distribution of ,osmundaceous ferns in the ,mesozoic era carries their history back to a still more remote past1 a conclusion which receives support from the records of the rocks4 ,the ,bracken fern which we regard as characteristically ,british is a cosmopolitan type2 it was found by ,treub among the pioneers of the ,new ,flora of ,krakatau2 in ,british ,central ,africa1 it greets one at every turn 8like a messenger from the homeland#gbf02 it grows on the ,swiss ,alps1 on the mountains of ,abyssinia1 in ,tasmania1 and on the slopes of the ,himalayas4 ,the two genera ,matonia 7fig4 #bbh7 and ,dipteris1 which grow side by side on ,mount ,ophir in the ,malay ,peninsula1 are examples of restricted geographical range and carry us back to the ,jurassic period when closely allied types flourished abundantly in northern latitudes4 ,similarly ,thyrsopteris elegans1 confined to ,juan ,fernandez1 exhibits a remarkable likeness to ,jurassic species from ,england and the ,arctic regions4 ,the proportion of ferns to flowering plants in recent floras is a question of some interest from a palaeobotanical point of view2 but we must bear in mind the fact that the evolution of angiosperms1 effected at a late stage in the history of the earth1 seriously disturbed the balance of power among competitors for earth and air4 ,the abundance of ferns in a particular region is1 however1 an unsafe guide to geographical or climatic conditions4 ,many ferns are essentially social plants2 the wide stretches of moorland carpeted with ,pteris aquilina afford an example of the monopolisation of the soil by a single species4 ,in ,sikkim ,sir ,joseph ,hooker speaks of extensive groves of tree ferns1 and in the wet regions of the ,amazon1 ,bates#gbg describes the whole forest glade as forming a 8vast fernery40 ,in a valley in ,tahiti ,alsophila tahitiensis is said to form 8a sort of forest almost to the exclusion of other ferns#gbh40 ,in the abundance of ,glossopteris 7figs4 #ccd1 etc47 fronds spread over wide areas of ,permo-,carboniferous rocks in ,s4 ,africa1 ,australia1 and ,india1 we have a striking instance of a similar social habit in an extinct fern or at least fern-like plant4 ,acrostichum aureum1 with pinnate fronds several feet long1 is an example of a recent fern covering immense tracts1 but this species#gbi is more especially interesting as a member of the ,filicineae characteristic of brackish marshes and the banks of tropical rivers in company with ,mangrove plants and the 8,stemless ,palm0 ,nipa4 ,this species exhibits the anatomical characters of a water-plant and affords an interesting parallel with some ,palaeozoic ferns 7species of ,psaronius7 which probably grew under similar conditions4 ,the ,anatomy of ,ferns4 ,the text-book accounts of fern-anatomy convey a very inadequate idea of the architectural characters displayed by the vascular systems of recent genera4 ,when we are concerned with the study of extinct plants it is essential to be familiar not only with the commoner recent types1 but particularly with exceptional or aberrant types4 ,the vascular system of many ferns consists of strands of xylem composed of scalariform tracheae associated with a larger or smaller amount of parenchyma1 surrounded either wholly or in part 7that is concentric or bicollateral7 by phloem3 beyond this is a pericycle1 one layer or frequently several layers in breadth1 limited externally by an endodermis1 which can usually be readily recognised4 ,the vascular strands are embedded in the ground-tissue of the stem consisting of thin-walled parenchyma and1 in most ferns1 a considerable quantity of hard and lignified mechanical tissue4 ,the narrow protoxylem elements are usually characterised by a spiral form of thickening1 but in slow-growing stems the first-formed elements are frequently of the scalariform type4 ,a study of the anatomy of recent ferns both in the adult state and in successive stages of development from the embryo has on the whole revealed 8a striking parallelism#gcj0 between vascular and sporangial characters in leptosporangiate ferns4 ,for a masterly treatment of our knowledge of fern anatomy from a phylogenetic point of view reference should be made to ,mr ,tansley's recently published lectures3 within the limits of this volume all that is possible is a brief outline of the main types of vascular structure illustrated by recent genera4 ,illustration3 ,,fig4 #bcg4 ,a4 ,matonia pectinata 7petiole74 ,b4 ,m4 pectinata 7stem74 ,c4 ,gleichenia dicarpa 7stem73 p1 petiole2 pp1 protophloem2 position of protoxylem indicated by black dots4 ,d4 ,matonidium4 ,e4 ,trichomanes reniforme3 pp1 protophloem4 7,c1 ,e1 after ,boodle2 ,d1 after ,bommer47 ,to ,prof4 ,jeffrey#gca we owe the term protostele which he applied to a type of stele consisting of a central core of xylem surrounded by phloem1 pericycle1 and endodermis4 ,while admitting that steles of this type may sometimes be the result of the modification of less simple forms1 we may confidently regard the protostele as representing the most primitive form of vascular system4 ,the genus ,lygodium affords an example of a protostelic fern2 a solid column of xylem tracheae and parenchyma is completely encircled by a cylinder of phloem succeeded by a multi-layered pericycle and an endodermis of a single layer of cells4 ,in this genus the stele is characterised by marginal groups of protoxylem2 it is exarch4 ,an almost identical type is represented by species of ,gleichenia1 but here the stele is mesarch1 the protoxylem being slightly internal 7fig4 #bcg1 ,c74 ,trichomanes scandens 7fig4 #bch7 has an exarch protostele like that of ,lygodium2 but1 as ,boodle#gcb has suggested1 the protostelic form in this case is probably the result of modification of a collateral form of stele such as occurs in ,trichomanes reniforme 7fig4 #bcg1 ,e74 ,a second type of stele has been described in species of ,lindsaya#gcc in which the xylem includes a small group of phloem near the dorsal surface4 ,this ,lindsaya type is often passed through in the development of 8seedling0 ferns and may be regarded as a stage in a series leading to another well-marked type1 the solenostele4 ,the solenostele#gcd1 a hollow cylinder of xylem lined within and without by phloem1 pericycle1 and endodermis1 occurs in several genera belonging to different families1 e4g4 ,dipteris1 species of ,pteris1 species of ,lindsaya1 ,polypodium1 ,jamesonia1 ,loxsoma1 ,gleichenia and other genera4 ,in a smaller number of ferns the stele consists of what may be called a medullated protostele similar to the common form of stele in ,lepidodendron3 this type is found in species of ,schizaea and in ,platyzoma 7fig4 #bci74 ,it is important to notice that in the solenostele and as a rule in the medullated protostele when a leaf-trace passes out from the rhizome stele the vascular cylinder is interrupted by the formation of a foliar gap 7,platyzoma#gce1 fig4 #bci1 is an exception74 ,this fact has been emphasized by ,jeffrey#gcf who draws a distinction between the ,lycopodiaceous type of stele1 which is not broken by the exit of leaf-traces1 and the fern stele in which foliar gaps are produced3 the former he speaks of as the cladosiphonic type 7,lycopsida7 and the latter as the phyllosiphonic 7,pteropsida74 ,illustration3 ,,fig4 #bch4 ,stele of ,trichomanes scandens3 px1 protoxylem2 s1 endodermis4 ,from ,tansley1 after ,boodle4 ,illustration3 ,,fig4 #bci4 ,platyzoma microphylla4 l4t41 leaf-trace2 i4e41 internal endodermis4 7,after ,tansley2 modified from ,boodle47 ,the transition to a hollow cylinder of xylem from a protostele may be described as the result of the replacement of some of the axial conducting tracheae by parenchyma or other non-vascular tissue consequent on an increase in diameter of the whole stele and the concentration of the true conducting elements towards the periphery#gcg4 ,the occurrence of the internal cylinder of phloem1 pericycle1 and endodermis in a solenostele is rendered intelligible by a study of fern seedlings and by a comparative examination of transitional types connecting protosteles and solenosteles through medullated protosteles and steles of the ,lindsaya type4 ,a further stage in stelar evolution is illustrated by what is termed the dictyostele1 the arrangement of vascular tissue characteristic of ,nephrodium ,filix-mas1 ,cyathea 7fig4 #bdj71 ,polypodium vulgare and many other common ferns4 ,illustration3 ,,fig4 #bdj4 ,cyathea ,imrayana4 7,from ,tansley after de ,bary47 7,sclerenchyma represented by black bands47 ,if a solenostele is interrupted by leaf-gaps at intervals sufficiently close to cause overlapping1 a transverse section at any part of the stele will show apparently separate curved bands of concentrically arranged xylem and phloem1 which on dissection are seen to represent parts of a continuous lattice-work or a cylinder with the wall pierced by large meshes4 ,the manner of evolution of the dictyostele has been ably dealt with by ,gwynne-,vaughan#gch and other authors4 ,in a few ferns1 e4g4 ,matonia pectinata#gci1 a transverse section of the stem 7fig4 #bcg1 ,b7 reveals the presence of two or in some cases three concentric solenosteles with a solid protostele in the centre3 this polycylic type may be regarded as the expression of the fact that in response to the need for an adequate water-supply to the large fronds1 ferns have increased the conducting channels by a method other than by the mere increase of the diameter of a single stele4 ,fig4 #bcg1 ,a1 shows the vascular tissue of a petiole of ,matonia in transverse section4 ,the two genera of ,osmundaceae1 ,todea and ,osmunda1 are peculiar among recent ferns in having a vascular cylinder composed of separate strands of xylem varying considerably in shape and size1 from ,u-shaped strands with the concavity facing the centre of the stem and with the protoxylem in the hollow of the ,u1 to oval or more or less circular strands with a mesarch protoxylem or without any protoxylem elements 7fig4 #bba1 ,a1 ,b74 ,these different forms are the expression of the change in contour or in structure which the parts of the lattice-work undergo at different levels in the stem#gdj4 ,beyond this ring of xylem bundles is a continuous sheath of phloem of characteristic structure4 ,a transverse section of a stem of ,osmunda regalis may show #ae or more xylem strands2 in ,o4 ,claytoniana there may be as many as #dj4 ,in ,todea barbara 7fig4 #bba1 ,b7 the leaf-gaps are shorter1 and in consequence of the less amount of overlapping the xylem cylinder becomes an almost continuous tube4 ,the recent researches of ,kidston and ,gwynne-,vaughan#gda have resulted in the discovery of fossil ,osmundaceous stems with a complete xylem ring1 the stele being of the medullated protostele type2 in another extinct member of the family the stele consists of a solid xylem core4 ,the ,osmundaceous type of stele is complicated in ,o4 cinnamomea 7fig4 #bba1 ,a7 by the occurrence of local internal phloem and by an internal endodermis1 a feature which leads ,jeffrey to what ,i believe to be an incorrect conclusion that the vascular arrangement found in ,osmunda regalis has been evolved by reduction from a stele in which the xylem was enclosed within and without by phloem4 ,new facts recently brought to light enable us to derive the ordinary ,osmundaceous type from the protostele and solenostele4 ,it is worthy of remark that the ,osmundaceae occupy a somewhat isolated position among recent ferns2 their anatomy represents a special type1 their sporangia differ in several respects from those of other leptosporangiate ferns and in some features ,osmunda and ,todea agree with the ,eusporangiate ferns4 ,the possession of such distinguishing characters as these suggests antiquity2 and the facts of palaeobotany1 as also the present geographical range of the family1 confirm the correctness of this deduction4 ,before leaving the stelar structure of leptosporangiate fern stems1 a word must be added in regard to a type of structure met with in the ,hymenophyllaceae4 ,in this family ,trichomanes reniforme 7fig4 #bcg1 ,e7 may be regarded1 as ,boodle suggests1 as the central type3 the stele consists of a ring of metaxylem tracheae1 the dorsal portion having the form of a flat arch and the ventral half that of a straight band4 ,this flattened ring of xylem encloses parenchymatous tissue containing scattered tracheae some of which are protoxylem elements4 ,in ,trichomanes radicans the rhizome is stouter than in ,t4 reniforme and the stele consists of a greater number of tracheae4 ,the stele is cylindrical like that shown in fig4 #bch1 but the centre is occupied by two groups of protoxylem and associated parenchyma4 ,in ,hymenophyllum tunbrigense the stele is of the subcollateral type2 the ventral plate of the xylem ring has disappeared leaving a single strand of xylem with endarch protoxylem and completely surrounded by phloem4 ,trichomanes muscoides possesses a still simpler stele consisting of a slender xylem strand with phloem on one side only4 ,reference has already been made to the occurrence in this family of the protostelic type4 ,the ,hymenophyllaceae afford a striking illustration of the modification in different directions of stelar structure connected with differences in habit1 and of the correlation of demand and supply as shown in the varying amount of conducting tissue in the steles of different species4 ,the leaf-trace in a great number of ferns is characterised by its ,c-shaped form#gdb as seen in transverse section3 this in some genera1 e4g4 ,matonia 7fig4 #bcg1 ,a71 is complicated by the spiral infolding of the free edges of the ,c2 in other ferns 7e4g4 some ,cyatheaceae7 7fig4 #bgh1 ,c7 the sides of the ,c are incurved1 while in some species the xylem is broken up into a large number of separate strands4 ,an elaborate treatment of the leaf-traces of ferns was published a few years ago by ,,mm4 ,bertrand and ,cornaille#gdc in which the authors show how the various systems of vascular tissue in the fronds of ferns maybe derived from a common type4 ,as ,prof4 ,chodat#gdd justly remarks this important work has not received the attention it deserves1 the neglect being attributed to the strange notation which is adopted#gde4 ,the roots of ferns are characterised by a uniformity of plan in marked contrast to the wide range of structure met with in the stem and to a less extent in the leaves4 ,the xylem may consist of a plate of scalariform tracheae with a protoxylem group at each end1 or the stele may include six or more alternating strands of xylem and phloem4 ,,ii4 ,marattiales 7,eusporangiate isosporous ,filicales74 ,the ,marattiaceae1 the single family of ferns included in the ,marattiales1 comprise the genera ,angiopteris1 ,archangiopteris1 ,marattia1 ,danaea1 and ,kaulfussia1 which are for the most part tropical in distribution4 ,these genera are characterised by eusporangiate sori or synangia1 the presence of stipules at the base of the petioles1 and by the complex arrangement of the vascular tissue4 ,in view of the fact that many fossil ferns show a close resemblance to the recent ,marattiaceae1 the surviving genera are briefly described4 ,the prothallus is green and relatively large4 ,angiopteris4 ,this genus occurs in ,polynesia1 tropical ,asia1 and ,madagascar2 it is characterised by a short and thick fleshy stem bearing large bipinnate leaves which occasionally show a forking of the rachis#gdf1 a feature reminiscent of some ,palaeozoic fern-like fronds4 ,one of the large plants of ,angiopteris evecta in the ,royal ,gardens1 ,kew1 bears leaves #ab feet in length with a stalk #f inches in diameter at the base4 ,the sessile or shortly stalked and rather leathery linear or broadly lanceolate pinnules have a prominent midrib and dichotomously branched lateral veins4 ,the surface of an old stem is covered with the thick stumps of petioles enclosed by pairs of fleshy stipules 7fig4 #bda1 ,a7 and bears numerous fleshy roots1 which hang free in the air or penetrate the soil4 ,the young fronds 7fig4 #bbj1 ,a7 exhibit very clearly the characteristic circinate vernation4 ,the proximal part of each primary pinna is characterised by a pulvinus-like swelling4 ,the sporangia1 in short linear elliptical sori near the edge of the pinnules1 consist of free sporangia 7fig4 #bdb1 ,a-,d7 provided with a peculiar type of 8annulus0#gdg1 in the form of a narrow band of thicker-walled cells1 which extends as a broad strip on either side of the apex4 ,an examination of sections through the sporangia of ,angiopteris in different planes#gdh illustrates the difficulty of determining the precise nature of the annulus in a petrified sporangium which is seen only in one or two planes4 ,many of the sporangia from the ,english ,coal-,measures1 compared by authors with those of ,leptosporangiate ferns1 are in all probability referable to the ,marattiaceous type4 ,illustration3 ,,fig4 #bda4 ,a4 ,angiopteris evecta4 7,considerably reduced47 ,b4 ,marattia fraxinea4 ,stipule4 ,m4,s4 ,the vascular system#gdi of the stem constitutes a highly complex dictyostelic or polycylic type which may consist of as many as nine concentric series of strands of xylem surrounded by phloem1 with large sieve-tubes and a pericycle which abuts on the parenchymatous ground-tissue without any definite endodermal layer4 ,a peculiarity in the vascular strands is that the first-formed elements of the phloem lie close to the edge of the xylem1 the metaphloem being therefore centrifugal in its development4 ,the ground-tissue is devoid of mechanical tissue and is penetrated by roots1 a few of which arise from the outer vascular strands while others force their way to the surface from the more internal dictyosteles4 ,leaf-traces1 consisting of several strands1 are given off from the outermost cylinder and a segment of the second dictyostele moves out to fill the gap formed in the outermost network1 while the gap in the second cylinder receives compensating strands from the third4 ,a few layers below the surface of the petiole there is a ring of thick-walled elements 7s1 fig4 #bdc71 and in both petiole and stem numerous mucilage ducts and tannin-sacs occur in the ground-tissue4 ,it has been shown by ,farmer and ,hill#gej that in some of the vascular strands in an ,angiopteris stem a few secondary tracheae are added to the primary xylem by the activity of the adjacent parenchyma4 ,the vascular bundles in the petiole form more or less regular concentric series2 they have no endodermis and are characterised also by the large size of the sieve-tubes 7st1 fig4 #bdc74 ,illustration3 ,,fig4 #bdb4 ,a-,d4 ,angiopteris evecta4 ,a4 ,apex of sporangium showing 8annulus40 ,b4 ,sori4 ,c4 ,sporangium4 ,d4 ,section of sporangium1 showing the two lateral bands of thick-walled cells4 ,e4 ,danaea3 a1 roof of synangium1 with pores2 b1 sporangial cavities2 v1 vascular bundle2 i1 indusium4 7,d1 after ,zeiller47 ,the roots of ,marattiaceous ferns 7fig4 #bdd7 are characterised by the larger number of xylem and phloem groups2 the stele is polyarch and not diarch1 tetrarch or hexarch as in most ,leptosporangiate ferns4 ,illustration3 ,,fig4 #bdc4 ,angiopteris evecta4 ,section of petiole 7considerably reduced7 and of a single vascular bundle 7magnified73 px1 protoxylem2 st1 sieve-tubes4 ,illustration3 ,,fig4 #bdd4 ,angiopteris evecta4 ,transverse section of root1 with part of the stele magnified3 s1 sieve-tubes2 p1 phloem2 px1 protoxylem4 ,archangiopteris4 ,this monotypic genus1 discovered by ,mr ,henry in ,south ,eastern ,yunnan1 was described by ,christ and ,giesenhagen in #ahiigea4 ,the comparatively slender rhizome has a fairly simple vascular system#geb4 ,the simply-pinnate leaves bear pinnules like those of ,danaea1 but the sori agree with those of ,angiopteris except in their greater length and in the larger number of sporangia4 ,marattia4 ,this genus1 which extends 8all round the world within the tropics#gec10 includes some species which closely resemble ,angiopteris1 while others are characterised by more finely divided leaves with smaller ultimate segments4 ,the fleshy stipules occasionally have an irregularly pinnatifid form 7fig4 #bda1 ,b74 ,the sporangia are represented by oval synangia#ged 7fig4 #bde1 ,a2 the black patches at the ends of the lateral veins7 composed of two valves1 which on ripening come apart and expose two rows of pores formed by the apical dehiscence of the sporangial compartments 7fig4 #bde1 ,a1 ,b74 ,in ,marattia ,kaulfussii the sori are attached to the lamina by a short stalk 7fig4 #bde1 ,b1 ,b7 and the leaf bears a close resemblance to those of the ,umbelliferous genera ,anthriscus and ,chaerophyllum4 ,the vascular system is constructed on the same plan as that of ,angiopteris but is of simpler form4 ,illustration3 ,,fig4 #bde4 ,a4 ,marattia fraxinea4 ,a4 ,a single synangium showing the two valves and pores of the sporangial compartments4 ,b1 ,b4 ,m4 ,kaulfussii4 ,c4 ,kaulfussia 7synangium showing pores of sporangial compartments74 ,d1 ,e4 ,marattiopsis ,mnsteri4 7,c1 after ,hooker2 ,d1 ,e1 after ,schimper47 ,danaea4 ,danaea1 represented by about #ad species confined to tropical ,america1 is characterised by simple or simply pinnate leaves with linear segments bearing elongated sori extending from the midrib almost to the margin of the lamina4 ,each sorus consists of numerous sporangia in two parallel rows united into an oblong mass partially overarched by an indusium 7fig4 #bdb1 ,e1 i7 which grows up from the leaf between the sori4 ,in the portion of a fertile segment shown in fig4 #bdb1 ,e1 the apical pores are seen at a2 and at b1 where the roof of the synangium has been removed1 the spore-bearing compartments are exposed4 ,the vascular system#gee agrees in general plan with that characteristic of the family4 ,kaulfussia4 ,the form of the leaf 7,vol4 ,i4 p4 #ig1 fig4 #bb7 closely resembles that of the ,horse ,chestnut2 the stem is a creeping dorsiventral rhizome with a vascular system in the form of a 8much perforated solenostele#gef40 ,the synangia are circular1 with a median depression2 each sporangial compartment opens by an apical pore on the sloping sides of the synangial cup 7fig4 #bde1 ,c7#geg4 ,copeland has recently described a ,marattiaceous leaf which he makes the type of a new genus1 ,macroglossum alidae4 ,the sori are nearer the margin than in ,angiopteris and are said to consist of a greater number of sporangia4 ,the photograph#geh of a single pinna which accompanies the brief description hardly affords satisfactory evidence in support of the creation of a new genus4 ,the structure of a petiole which ,i have had an opportunity of examining1 through the kindness of ,mr ,hewitt of ,sarawak1 shows no distinctive features4 ,,iii4 ,ophioglossales4 7,isosporous and ,eusporangiate47 ,the three genera1 ,ophioglossum1 ,botrychium1 and ,helminthostachys1 are characterised by the division of the leaves into a sterile and a fertile lobe4 ,the fertile lobe in ,ophioglossum bears two rows of spherical sporangia sunk in its tissue2 in ,botrychium and ,helminthostachys the spores are contained in large sporangia with a stout wall#gei4 ,the prothallus is subterranean and without chlorophyll4 ,in the ,british species of ,ophioglossum1 ,o4 vulgatum 7the adder's tongue fern71 an almost cosmopolitan species1 the sterile part of the frond is of oval form and has reticulate venation4 ,in ,o4 pendulum and ,o4 palmatum the lamina is deeply lobed4 ,in the genus ,botrychium1 represented in ,britain by ,b4 ,lunaria1 both sterile and fertile branches of the frond are pinnately divided1 while in ,helminthostachys the sporangia are borne on sporangiophores given off from the margin of the fertile branch of a frond similar in habit to a leaf of ,helleborus4 ,illustration3 ,,fig4 #bdf4 ,ophioglossum vulgatum4 ,transverse section of petiole and single bundle3 p1 phloem2 px1 endarch protoxylem4 ,illustration3 ,,fig4 #bdg4 ,botrychium virginianum3 e1 endodermis2 c1 cambium2 x1 xylem4 ,a1 diagrammatic section of stem2 ,b1 portion of the stele and endodermis enlarged4 7,a1 after ,campbell2 ,b1 after ,jeffrey47 ,the stem of ,ophioglossum is characterised by a dictyostele of collateral bundles with endarch protoxylem3 the vascular system of the leaf-stalk is also composed of several separate strands 7fig4 #bdf74 ,in ,botrychium the stele is a cylinder of xylem surrounded externally by phloem4 ,this genus affords the only instance among ferns of a plant in which the addition of secondary tracheae occurs on a scale large enough to produce a well-defined cylinder of secondary xylem traversed by radial rows of medullary-ray cells#gfj 7fig4 #bdg74 ,the unsatisfactory nature of the evidence in regard to the past history of the ,ophioglossales renders superfluous a fuller treatment of the recent species4 ,,chapter ,,xxi4 ,,fossil ,,ferns4 ,osmundaceae4 ,from the ,culm of ,silesia1 ,stur#gfa described impressions of sterile fronds which he named ,todea ,lipoldi on the ground of the similarity of the finely divided pinnules to those of ,todea superba and other filmy species of the genus4 ,the type-specimen of ,stur 7in the ,geological ,survey ,museum1 ,vienna7 affords no information as to sporangial characters and cannot be accepted as an authentic record of a ,lower ,carboniferous representative of the family4 ,another more satisfactory but hardly convincing piece of evidence bearing on the presence of ,osmundaceae in pre-,permian floras has been adduced by ,renault#gfb1 who described petrified sporangia from the ,culm beds of ,esnost in ,france as ,todeopsis primaeva 7fig4 #bef1 ,f74 ,these pyriform sporangia are characterised by the presence of a plate of large cells comparable with the subapical group of 8annulus0 cells in the sporangia of the recent species 7fig4 #bba74 ,zeiller#gfc has published a figure of some sporangia described by ,renault from ,autun resembling the ,osmundaceous type in having a plate of thick-walled cells instead of a true annulus1 but the plate is larger than the group of cells in the recent sporangia1 and both sporangia and spores are smaller in the fossil4 ,the sporangia from ,carboniferous rocks described by ,weiss as ,sturiella#gfd bear some resemblance to those of recent ,osmundaceae1 but there is no adequate reason for referring them to this family4 ,the generic name ,pteridotheca is employed by ,scott as a convenient designation for unassigned petrified sporangia of ,palaeozoic age with an annulus and other characters indicating fern-affinity4 ,in the species ,p4 ,butterworthi#gfe the sporangia are characterised by a group of large cells suggesting comparison with the annulus1 or what represents the annulus1 in ,osmundaceae and ,marattiaceae4 ,scott has also described a sporangium from the ,coal-,measures containing germinating spores#gff2 the structure is similar to that of recent ,osmundaceous sporangia1 and it is interesting to note that germinating spores have been observed in the recent species ,todea hymenophylloides#gfg4 ,additional evidence of the same kind is afforded by fertile specimens of a quadripinnate fern with deeply dissected oval-lanceolate pinnules described by ,zeiller from the ,coal-,measures of ,heraclea in ,asia ,minor as ,kidstonia heracleensis#gfh 7fig4 #bef1 ,e74 ,carbonised sporangia were found at the base of narrow lobes of the ultimate segments and1 as seen in fig4 #bef1 ,e1 the sporangial wall is distinguished by a plate of larger cells occupying a position like that of the 8annulus0 of recent ,osmundaceae4 ,zeiller regards the sporangia as intermediate between those of ,osmundaceae and ,schizaeaceae4 ,from the same locality ,zeiller describes another frond bearing somewhat similar sporangia as ,sphenopteris 7,discopteris7 ,rallii 7fig4 #bef1 ,d7#gfi3 the term ,discopteris was instituted by ,stur for fertile fronds referred by him to the ,marattiaceae#ggj4 ,it is by no means safe to assume that these and such ,upper ,carboniferous sporangia as ,bower#gga compared with those of ,todea were borne on plants possessing the anatomical characters of ,osmundaceae rather than those of the extinct ,palaeozoic family ,botryopterideae4 ,this brings us to the important fact1 first pointed out by ,renault1 that the ,botryopterideae are essentially generalised ferns exhibiting many points of contact with the ,osmundaceae#ggb4 ,it is clear that whether or not we are justified in tracing the ,osmundaceae as far back as the ,lower ,carboniferous period1 some of the characteristics of the family were already foreshadowed in rocks of this age4 ,through a fortunate accident of preservation1 unequivocal evidence of the existence of ,osmundaceae in the ,palaeozoic era is supplied by the ,russian ,upper ,permian genera ,zalesskya and ,thamnopteris4 ,zalesskya4 ,this generic title has been instituted by ,kidston and ,gwynne-,vaughan#ggc for two ,russian stems of ,upper ,permian age1 one of which was named by ,eichwald#ggd ,chelepteris gracilis1 but the probability that the type of the genus ,chelepteris is generically distinct from ,eichwald's species necessitated a new designation for the ,permian fern4 ,in habit the stem of ,zalesskya resembles that of an ,osmunda or a ,todea1 but it differs in the possession of a stele composed of a continuous cylinder or solid column of xylem surrounded by phloem1 and by the differentiation of the xylem into two concentric zones4 ,the leaves are represented by petiole-bases only2 the sporangia are unknown4 ,the stem and leaf-base anatomy fully justifies the inclusion of ,zalesskya in the ,osmundaceae4 ,zalesskya gracilis 7,eichwald74 ,fig4 #bdh4 ,the type-specimen is a partially decorticated stem1 from ,upper ,permian beds in ,russia1 provided with a single stele1 #ac mm4 in diameter1 surrounded by a broad thin-walled inner cortex containing numerous leaf-traces and occasional roots3 this was doubtless succeeded by a sclerotic outer cortex4 ,in its main features ,zalesskya gracilis agrees closely with ,z4 diploxylon represented in fig4 #bdi4 ,the stele consists of a continuous cylinder of xylem exhibiting a fairly distinct differentiation into two zones1 7i7 a broader outer zone of narrower scalariform tracheae 7x ii1 fig4 #bdh7 in which #bj to #be protoxylem strands 7px7 occur just within the edge1 7ii7 an inner zone of broader and shorter tracheae 7fig4 #bdh1 x i74 ,the protoxylem elements 7px1 fig4 #bdh7 are characterised by a single series of scalariform pits1 while the metaxylem elements have multiseriate pits like those on the water-conducting elements of recent ,osmundaceae4 ,the tracheae show an interesting histological character in the absence of the middle substance of their walls1 a feature recognised by ,gwynne-,vaughan#gge in many recent ferns4 ,external to the xylem and separated from it by a parenchymatous sheath is a ring of phloem1 ph1 composed of large sieve-tubes and parenchyma separated from the inner cortex by a pericycle #d to #e layers in breadth4 ,the occurrence of a few sclerotic cells beyond the broad inner cortex points to the former existence of a thick-walled outer cortex4 ,the leaf-traces are given off as mesarch strands from the edge of the xylem2 they begin as prominences opposite the protoxylem and become gradually detached as xylem bundles1 at first oblong in transverse section1 then assuming a slightly crescentic and reniform shape1 while the mesarch protoxylem strand takes up an endarch position4 ,as a trace passes further out the curvature increases and the protoxylem strands undergo repeated bifurcation2 it assumes in fact the form and general type of structure met with in the leaf-traces of ,todea and ,osmunda4 ,numerous diarch roots1 given off from the stele at points just below the outgoing leaf-traces1 pass outwards in a sinuous horizontal course through the cortex of the stem4 ,illustration3 ,,fig4 #bdh4 ,zalesskya gracilis 7,eich474 ,transverse section of part of the stele3 ph1 phloem2 x i1 x ii1 xylem2 px1 protoxylem4 7,after ,kidston and ,gwynne-,vaughan4 #bj47 ,illustration3 ,,fig4 #bdi4 ,zalesskya diploxylon4 ,kidston and ,gwynne-,vaughan4 ,transverse section of stem4 ph1 phloem4 7,after ,kidston and ,gwynne-,vaughan4 #b47 ,in ,zalesskya gracilis the xylem cylinder was probably wider in the living plant than in the petrified stem4 ,in ,zalesskya diploxylon#ggf1 in all probability from the same ,russian locality1 there can be little doubt that the xylem was originally solid to the centre 7fig4 #bdi74 ,in this species also the phloem forms a continuous band 7ph1 fig4 #bdi7 consisting of four to six layers of sieve-tubes4 ,thamnopteris4 ,thamnopteris ,schlechtendalii 7,eich474 ,figs4 #bej1 #cab1 ,a1 ,frontispiece4 ,in #ahdi ,brongniart#ggg proposed the name ,thamnopteris for a species of fern from the ,upper ,permian of ,russia originally described by ,eichwald as ,anomopteris ,schlechtendalii4 ,a new name was employed by ,brongniart on the ground that the fossil was not generically identical with the species previously named by him ,anomopteris ,mougeotii#ggh4 ,eichwald's specimen has been thoroughly investigated by ,kidston and ,gwynne-,vaughan#ggi4 ,the stem 7,frontispiece7 agrees in habit with those of ,zalesskya and recent ,osmundaceae2 on the exposed leaf-bases the action of the weather has etched out the horse-shoe form of the vascular strands and laid bare numerous branched roots boring their way through the petiole stumps4 ,the centre of the stem is occupied by a protostele #ac mm4 in diameter consisting of solid xylem separated by a parenchymatous sheath from a cylinder of phloem4 ,the xylem is composed mainly of an axial column of short and broad reticulately pitted tracheae 7fig4 #bej1 b and ,frontispiece71 distinguished from the sharply contrasted peripheral zone of normal scalariform elements1 a1 by their thinner walls and more irregular shape4 ,the protoxylem1 px1 is represented by groups of narrower elements rather deeply immersed in the peripheral part of the metaxylem4 ,a many-layered pericycle1 per1 and traces of an endodermis1 en1 succeed the phloem1 ph1 which is characterised by several rows of large contiguous sieve-tubes2 beyond the endodermis is a broad thin-walled inner cortex4 ,the leaf-traces arise as in ,zalesskya1 but the protoxylem in ,thamnopteris is at first central2 as the trace passes outwards a group of parenchyma appears immediately internal to the protoxylem elements and gradually assumes the form of a bay of thin-walled tissue on the inner concave face of the curved xylem4 ,the next stage is the repeated division of the protoxylem strand until1 in the sclerotic outer cortex1 the traces acquire the ,osmundaceous structure 7fig4 #cab1 ,a1 p4 #dec74 ,the petiole bases have stipular wings as in ,todea and ,osmunda4 ,illustration3 ,,fig4 #bej4 ,thamnopteris ,schlechtendalii 7,eich474 ,part of stele3 a1 outer xylem2 b1 inner xylem4 7,after ,kidston and ,gwynne-,vaughan4 #ac47 ,sidenote3 ,,osmundaceae ,the striking feature exhibited by these ,permian plants is the structure of the protostele1 which in ,thamnopteris and probably in ,zalesskya diploxylon consists of solid xylem surrounded by phloem3 this may be regarded as the primitive form of the ,osmundaceous stele4 ,in ,osmunda regalis and in other recent species of the genus the xylem cylinder has the form of a lattice-work2 in other words1 the departure of each leaf-trace makes a gap in the xylem and the overlapping of the foliar-gaps results in the separation of the xylem into a number of distinct bundles4 ,in ,zalesskya gracilis the continuity of the xylem is not broken by overlapping gaps2 in this it agrees with ,lepidodendron4 ,in ,thamnopteris the centre of the stele was occupied by a peculiar form of xylem obviously ill-adapted for conduction1 but probably serving for water-storage and comparable with the short and broad tracheae in ,megaloxylon#ghj4 ,there is clearly a well-marked difference in stelar anatomy between these two ,permian genera and ,todea and ,osmunda3 this difference appears less when viewed in the light of the facts revealed by a study of the ,jurassic species ,osmundites ,dunlopi4 ,illustration3 ,,fig4 #bea4 ,lonchopteris virginiensis4 7,after ,fontaine4 nat4 size47 ,as possible examples of ,triassic ,osmundaceae reference may be made to some species included in ,stur's genus ,speirocarpus#gha4 ,s4 virginiensis was originally described by ,fontaine#ghb from the ,upper ,triassic rocks of ,virginia as ,lonchopteris virginiensis 7fig4 #bea7 and has recently been figured by ,leuthardt#ghc from the ,keuper of ,basel4 ,the sporangia1 which are scattered over the lower surface of the pinnules1 are described as globose-elliptical and as having a rudimentary apical annulus2 no figures have been published4 ,in habit the frond agrees with ,todites ,williamsoni1 but the lateral veins form an anastomosing system like that in the ,palaeozoic genus ,lonchopteris 7fig4 #bij1 ,b74 ,there would seem to be an a priori probability of this species being a representative of the ,osmundaceae and not1 as ,stur believed1 of the ,marattiaceae4 ,seeing that ,lonchopteris is a designation of a purely provisional kind1 it would be convenient to institute a new generic name for ,triassic species having the ,lonchopteris venation1 which there are good reasons for regarding as ,osmundaceous ferns4 ,similarly ,speirocarpus tenuifolius 7,emmons7 7 ,acrostichites tenuifolius ,font471 which resembles ,todites ,williamsoni 7see p4 #cci7 not only in habit and in the distribution of the sporangia but also in the venation1 is probably an ,osmundaceous species4 ,osmundites4 ,osmundites ,dunlopi1 ,kidston and ,gwynne-,vaughan#ghd1 fig4 #beb4 ,this species was found in ,jurassic rocks in the ,otago district of ,new ,zealand in association with ,cladophlebis denticulata#ghe 7fig4 #beg74 ,the type-specimen forms part of a stem #ag mm4 in diameter surrounded by a broad mass of crowded leaf-bases4 ,the stele consists of an almost continuous xylem ring 7fig4 #beb7 enclosing a wide pith3 the phloem and inner cortex are not preserved but the peripheral region of the stem is occupied by a sclerotic outer cortex4 ,the mass of encasing leaf-bases resolves itself on closer inspection into zones of foliage-leaf petioles and the petioles of scale-leaves with an aborted lamina4 ,a similar association of two forms of leaf is seen in the existing ,american species ,osmunda ,claytoniana and ,o4 cinnamomea4 ,the cortex and armour of leaf-bases are penetrated by numerous diarch roots4 ,the xylem cylinder1 six to seven tracheae broad1 is characterised by the narrower diameter of its innermost elements and--an important point--by the fact that the detachment of a leaf-trace does not break the continuity of the xylem cylinder 7fig4 #beb74 ,each leaf-trace is at first elliptical in section2 it then becomes curved inwards and gradually assumes the horse-shoe form as in ,zalesskya and in the recent species4 ,the single endarch protoxylem becomes subdivided until in the petiole it is represented by #bj or more strands4 ,illustration3 ,,fig4 #beb4 ,osmundites ,dunlopi ,kidst4 and ,g4-,v4 ,portion of xylem showing the departure of a leaf-trace4 7,after ,kidston and ,gwynne-,vaughan2 #cf47 ,in the continuity of the xylem cylinder this species of ,osmundites shows a closer approach to ,todea barbara or ,t4 superba 7fig4 #bba1 ,b7 than to species of ,osmunda2 it differs from ,zalesskya in having reached a further stage in the reduction of a solid protostele to one composed of a xylem cylinder enclosing a pith4 ,this difference is of the same kind as that which distinguishes the stele of ,lepidodendron rhodumnense from ,l4 ,harcourtii4 ,in ,lepidodendron short tracheae occasionally occur on the inner edge of the xylem cylinder1 and in recent species of ,todea the same kind of reduced tracheae are met with on the inner edge of the xylem#ghf4 ,in both cases the short tracheae are probably vestiges of an axial strand of conducting elements which in the course of evolution have been converted into parenchymatous cells4 ,in ,lepidodendron vasculare the mixed parenchyma and short tracheae in the centre of the stele represent an intermediate stage in xylem reduction1 and the arrangement in vertical rows of the medullary parenchyma in ,lepidodendron is precisely similar to that described by ,kidston and ,gwynne-,vaughan in ,thamnopteris4 ,in both cases the rows of superposed short cells have probably been produced by the transverse septation of cells which began by elongating as if to form conducting tubes and ended by assuming the form of vertical series of parenchymatous elements4 ,illustration3 ,,fig4 #bec4 ,osmundites ,kolbei ,sew4 7 nat4 size47 ,in another ,jurassic species1 ,osmundites ,gibbiana#ghg1 the xylem is of the ,osmunda type and consists of about #bj strands instead of a continuous or almost continuous cylinder4 ,illustration3 ,,fig4 #bed4 ,osmundites ,kolbei4 7,leaf-scars47 ,osmundites ,kolbei ,seward1 figs4 #bec-bee4 ,this species was founded on a specimen obtained by ,mr ,kolbe from the ,uitenhage series of ,cape ,colony#ghh4 ,the fossil flora and fauna of this series point to its correlation with the ,wealden or ,neocomian strata of ,europe#ghi4 ,the type-specimen consists of several pieces of a stem 7fig4 #bec7 which reached a length of about #ij cm4 ,on the weathered surface the remains of petiole-bases are clearly seen and on the reverse side of the smaller piece shown in the figure numerous sinuous roots are present in association with the leaf-stalks4 ,the depression c in the larger specimen may mark the position of a branch3 at a fig4 #bec 7enlarged in fig4 #bed1 a7 the vascular strand of a petiole is exposed as a broad ,u-shaped band and at b 7fig4 #bed1 b7 the form of the petiole-bases is clearly shown#gij4 ,with the stem were found imperfectly preserved impressions of fronds referred to ,cladophlebis denticulata1 a common type of leaf which was found also in association with the slightly older ,new ,zealand stem1 ,osmundites ,dunlopi4 ,illustration3 ,,fig4 #bee4 ,osmundites ,kolbei ,sew4 ,transverse section1 from a photograph supplied by ,dr ,kidston and ,mr ,gwynne-,vaughan4 7#b nat4 size47 ,an examination of the internal structure of the ,south ,african stem by ,dr ,kidston and ,mr ,gwynne-,vaughan has revealed many interesting features1 which will be fully described in ,part ,,iv4 of their ,monograph on fossil ,osmundaceous stems4 ,i am greatly indebted to these authors for allowing me to publish the following note contributed by ,dr ,kidston3-- 8,the section of ,osmundites ,kolbei ,seward1 shown in fig4 #bee1 presents the usual appearance of an ,osmundaceous stock4 ,the parts contained in this section are the stele1 inner and outer cortex and a portion of the surrounding mantle of concrescent leaf-bases4 ,the whole specimen has suffered much from pressure1 but if restored to its original form the xylem ring must have been about #ai mm4 in diameter4 ,the number of xylem strands is about fifty-six and several of them are more or less joined as in the modern genus ,todea4 ,the tracheae are of the typical ,osmundaceous type1 that is to say1 the pits are actual perforations and several series of them occur on each wall of the larger tracheae4 8,the most interesting structural characteristic of ,osmundites ,kolbei is not well seen in the figure owing to the compression of the xylem ring4 ,this consists in the occurrence of tracheae in the pith4 ,in fact1 we have here a mixed pith1 composed of parenchyma and true tracheae1 a condition which connects the ,osmundaceae with a parenchymatous medulla with those possessing a solid xylem stele like ,zalesskya and ,thamnopteris and so completes the series of transitions extending from the older and solid-steled forms to the modern medullated members of the ,osmundaceae40 ,osmundites skidegatensis1 ,penhallow4 ,this lower ,cretaceous ,canadian species1 first described by ,penhallow#gia and more recently by ,kidston and ,gwynne-,vaughan#gib1 is remarkable for the large size of the stem1 the stele alone having a diameter of #bd cm4 ,penhallow figures a fragment of a leaf bearing a superficial resemblance to that of ,osmunda ,claytoniana1 which may be the foliage borne by ,osmundites skidegatensis4 ,the xylem cylinder is broken by the exit of leaf-traces into #ej or more strands varying in size and shape1 and it is noteworthy that the phloem is also interrupted as each leaf-trace is given off4 ,in recent species the xylem cylinder is almost always interrupted1 but the phloem retains its continuity4 ,in the ,canadian fossil an internal band of phloem occurs between the xylem and the pith1 and this joins the external phloem at each leaf-gap4 ,this internal phloem finds an interesting parallel in certain recent species#gic1 but in these the internal and external phloem do not meet at the foliar gaps as they do in the extinct type4 ,in ,osmunda cinnamomea the internal phloem occurs only at the regions of branching of the stem stele2 in the fossil it is always present4 ,it is clear that ,osmundites skidegatensis represents the most complex type of stem so far recognised in the ,osmundaceae2 it illustrates a stage in elaboration of the primitive protostele in advance of that reached by any existing species4 ,the primitive ,osmundaceous stele was composed of solid xylem surrounded by phloem 7,thamnopteris and ,zalesskya72 at a later stage the xylem cylinder lost its inner zone of wide and short tracheae and assumed the form seen in ,osmundites ,kolbei1 in which the centre of the stele consists of parenchyma with some tracheae4 ,another type is represented by ,o4 ,dowkeri in which the pith is composed wholly of parenchyma and the xylem ring is continuous4 ,from this type1 by expansion of the xylem ring and by the formation of overlapping leaf-gaps1 the form represented by ,osmunda regalis was reached4 ,osmunda cinnamomea1 with internal phloem in the regions of stelar branching1 probably represents a further stage1 as ,kidston and ,gwynne-,vaughan believe1 in increasing complexity due to the introduction of phloem from without through gaps produced by the branching of the stele4 ,in ,osmundites skidegatensis the leaf-gaps became wider and the external phloem projected deeper into the stele until a continuous internal phloem zone was produced4 ,this most elaborate type proved less successful than the simpler forms which still survive4 ,osmundites ,sturii4 ,impressions of fertile pinnae with narrow linear segments bearing exannulate sporangia described by ,raciborski from ,lower ,jurassic rocks in ,poland as ,osmunda ,sturii#gid may with some hesitation be included in the list of ,mesozoic ,osmundaceae4 ,osmundites ,dowkeri4 ,under this name ,carruthers#gie described a petrified stem from ,lower ,eocene beds at ,herne ,bay1 which in the structure of the stele agrees closely with the ,jurassic species ,o4 ,gibbiana and conforms to the normal ,osmundaceous type4 ,it is possible1 as ,gardner and ,ettingshausen#gif suggested1 that the foliage of this species may be represented by some sterile ,osmunda-like fragments recorded from the ,middle ,bagshot beds of ,bovey ,tracey and ,bournemouth as ,osmunda lignitum4 ,todites4 ,this generic name#gig has been applied to fossil ferns exhibiting in the structure of the sporangia and in the general habit of the fertile fronds a close resemblance to the recent species ,todea barbara 7fig4 #bba1 ,d1 p4 #bhf74 ,todites ,williamsoni 7,brongniart7 figs4 #bef1 ,b1 ,c1 ,g4 #ahbh4 ,pecopteris ,williamsonis1 ,brongniart1 ,prodrome1 p4 #eg2 ,hist4 vg4 foss41 p4 #cbd1 ,pl4 ,,cx4 figs4 #a and #b4 ---- ,p4 whitbiensis1 ,brongniart1 ,hist4 vg4 foss4 p4 #cba1 ,pl4 ,,cix4 figs4 #b-d4 ---- ,p4 tenuis1 ibid4 p4 #cbb1 ,pl4 ,,cx4 figs4 #c1 #d4 #ahbi4 ,pecopteris recentior1 ,phillips1 ,geol4 ,yorks4 p4 #adh1 ,pl4 ,,viii4 fig4 #ae4 ---- ,p4 curtata1 ibid4 ,pl4 ,,viii4 fig4 #ab4 #ahcc4 ,neuropteris recentior1 ,lindley and ,hutton1 ,foss4 ,flora1 ,vol4 ,i4 ,pl4 ,,lxviii4 ---- ,pecopteris dentata1 ibid4 ,vol4 ,,iii41 ,pl4 ,,clxix4 #ahcf4 ,acrostichites ,williamsonis1 ,goeppert1 foss4 ,farn4 p4 #bhe4 #ahda4 ,neuropteris ,goeppertiana1 ,muenster1 in ,goeppert1 ,gattungen foss4 ,pflanz4 ,lief4 #e and #f1 p4 #ajd1 ,pls4 ,,viii4-,x4 #ahef4 ,pecopteris ,huttoniana1 ,zigno1 ,flor4 foss4 ,oolit4 ,vol4 ,i4 p4 #acc4 #ahfg4 ,acrostichites ,goeppertianus1 ,schenk1 ,foss4 ,flor4 ,grenzsch4 p4 #dd1 ,pl4 ,v4 fig4 #e1 ,pl4 ,,vii4 fig4 #b4 #ahhc4 ,a4 linnaeaefolius1 ,fontaine1 ,older ,mesoz4 ,flora ,virginia1 p4 #be1 ,pls4 ,,vi4-,,ix4 -- ,a4 rhombifolius1 ibid4 ,pls4 ,,viii4 ,,xi4-,,xiv4 #ahhe4 ,todea ,williamsonis1 ,schenk1 ,palaeont4 ,vol4 ,,xxxi4 p4 #afh1 ,pl4 ,,iii4 fig4 #c4 #ahhi4 ,cladophlebis virginiensis1 ,fontaine1 ,potomac ,flora1 p4 #gj1 ,pl4 ,,iii4 figs4 #c-h2 ,pl4 ,,iv4 figs4 #a1 #d4 ,illustration3 ,,fig4 #bef4 ,a4 ,cladophlebis denticulata4 ,b1 ,b4 ,todites ,williamsoni 7fertile74 ,c4 ,t4 ,williamsoni 7sterile pinna74 ,d4 ,discopteris ,rallii4 ,e1 ,e4 ,kidstonia heracleensis4 ,f4 ,todeopsis primaeva4 ,g4 ,todites ,williamsoni 7sporangium74 ,b1 ,c1 from specimens 7#acdia2 #cibcd7 in the ,british ,museum 7,b1 very slightly reduced2 ,c1 nat4 size72 ,d1 ,e1 after ,zeiller2 ,f1 after ,renault2 ,g1 after ,raciborski4 ,it is hopeless to attempt to arrive at satisfactory conclusions in regard to the applicability of the name ,todites ,williamsoni to the numerous fronds from ,jurassic and ,rhaetic rocks1 agreeing more or less closely with ,brongniart's type-specimen4 ,specimens from the ,rhaetic may not be specifically identical with those from the ,jurassic2 the main point is that1 whether actually identical or not1 both sets of fossils clearly represent the same general type of ,osmundaceous fern#gih and may for present purposes be included under the same designation4 ,the above synonymy1 though by no means complete#gii1 serves to illustrate the confusion which has existed in regard to this widely spread type of ,mesozoic fern4 ,todites ,williamsoni may be briefly described as follows3-- ,frond bipinnate2 long linear pinnae 7#bj-cj cm47 of uniform breadth arise at an acute angle1 or in the lower part of a frond1 almost at right angles1 from a stout rachis4 ,closely set pinnules attached by a broad base2 slightly falcate1 the side towards the rachis strongly convex and the outer margin straight or concave and bulged outwards towards the base of each segment1 margin usually entire1 or it may be slightly lobed4 ,fertile pinnules similar to the sterile2 sporangia of the ,osmundaceous type and often scattered over the whole lower surface of the lamina 7fig4 #bef1 ,b1 ,b1 ,g74 ,venation of the ,cladophlebis type 7cf4 fig4 #bef1 ,a74 ,it is not always easy to distinguish ,todites ,williamsoni from ,cladophlebis denticulata1 another common ,jurassic fern1 but in the latter the pinnules are usually longer and relatively narrower and the rachis is more slender 7cf4 fig4 #bef1 ,b and #beg74 ,schenk#hjj and ,raciborski#hja have shown that the sporangia of ,todites conform in the absence of a true annulus to those of ,todea 7fig4 #bef1 ,g7 and ,osmunda4 ,nathorst#hjb has recently figured a group of spores of ,todites ,williamsoni in illustration of the use of the treatment of carbonised impressions with nitric acid and potassium chlorate4 ,this species1 though widely distributed in ,jurassic rocks1 is hardly distinguishable from the ,german ,rhaetic fronds figured by ,schenk from ,bayreuth as ,acrostichites ,goeppertianus#hjc1 or from other fossils referred to an unnecessarily large number of species by ,fontaine#hjd from ,upper ,triassic rocks of ,virginia#hje4 ,it would seem from the paucity of later records of ,osmundaceae that the family reached its zenith in the ,jurassic era4 ,when we pass to the later ,tertiary and more recent deposits evidence is afforded in regard to the geographical range of ,osmunda regalis4 ,it has been shown to occur in the ,pliocene forest-bed of ,norfolk#hjf as well as in ,palaeolithic and ,neolithic deposits#hjg4 ,illustration3 ,,fig4 #beg4 ,cladophlebis denticulata4 7,from a specimen in the ,british ,museum from the ,inferior ,oolite rocks of ,yorkshire4 ,slightly reduced47 ,a fertile frond from the ,molteno 7,rhaetic7 beds of ,south ,africa referred to ,cladophlebis 7,todites7 ,roesserti 7,presl7#hjh represents in all probability an ,osmundaceous fern closely allied to ,todites ,williamsoni4 ,the same species is described by ,zeiller#hji from ,rhaetic rocks of ,tonkin and very similar types are figured by ,leuthardt#haj from ,upper ,triassic rocks of ,basel as ,pecopteris ,rutimeyeri ,heer1 and by ,fontaine#haa from rocks of the same age in ,virginia4 ,cladophlebis4 ,the generic name ,cladophlebis was instituted by ,brongniart for ,mesozoic fern fronds characterised by ultimate segments of linear or more or less falcate form attached to the pinnae by the whole of the base1 as in the ,palaeozoic genus ,pecopteris1 possessing a midrib strongly marked at the base and dividing towards the distal end of the lamina into finer branches and giving off secondary forked and arched veins at an acute angle4 ,the term is generally restricted to ,mesozoic fern fronds which1 on account of the absence or imperfection of fertile pinnae1 cannot be safely assigned to a particular family4 ,in the case of the species described below1 the evidence in regard to systematic position1 though not conclusive1 is sufficiently strong to justify its inclusion in the ,osmundaceae4 ,cladophlebis denticulata ,brongniart4 ,figs4 #bef1 ,a2 #beg1 #beh4 #ahbh4 ,pecopteris denticulata#hab1 ,brongniart1 ,prodrome1 p4 #eg2 ,hist4 vg4 foss4 p4 #cja1 ,pl4 ,,xcviii4 figs4 #a1 #b4 -- ,p4 ,phillipsii1 ,brongniart1 ,hist4 p4 #cjd1 ,pl4 ,,cix4 fig4 #a4 ,this species is often confused#hac with ,todites ,williamsoni4 ,the name ,pecopteris whitbiensis has been used by different writers for ,jurassic fronds which are undoubtedly specifically distinct3 specimens so named by ,brongniart should be referred to ,todites ,williamsoni1 while ,p4 whitbiensis of ,lindley and ,hutton#had is ,brongniart's ,cladophlebis denticulata4 ,it is impossible to determine with accuracy the numerous examples described as ,pecopteris whitbiensis1 ,asplenium whitbiense1 ,cladophlebis ,albertsii 7a ,wealden species#hae71 ,asplenium1 or ,cladophlebis1 nebbense#haf1 etc41 from ,jurassic and ,rhaetic strata4 ,the ,cladophlebis denticulata form of frond is one of the commonest in recent ferns2 it is represented by such species as ,onoclea ,struthopteris1 ,pteris arguta1 ,sadleria sp41 ,gleichenia dubia1 ,alsophila lunulata1 ,cyathea dealbata1 and species of ,polypodium4 ,it is1 therefore1 not surprising to find records of this ,mesozoic species from many localities and horizons4 ,all that we can do is to point out what appear to be the most probable cases of identity among the numerous examples of fronds of this type from ,mesozoic rocks1 particularly ,rhaetic and ,jurassic1 in different parts of the world4 ,the name ,cladophlebis denticulata may be employed in a comprehensive sense for fronds showing the following characters3-- ,leaf large1 bipinnate1 with long spreading pinnae borne on a comparatively slender rachis4 ,pinnules1 in nearly all cases1 sterile1 reaching a length of #c-d;cm41 acutely pointed1 finely denticulate or entire1 attached by the whole of the base 7fig4 #beg74 ,in the apical region the pinnules become shorter and broader4 ,venation of the ,cladophlebis type 7fig4 #bef1 ,a74 ,fertile pinnules rather straighter than the sterile1 characterised by linear sori parallel to the lateral veins 7fig4 #beh74 ,in endeavouring to distinguish specifically between fronds showing a general agreement in habit with ,c4 denticulata1 special attention should be paid to venation characters1 the shape of the pinnules1 the relation of the two edges of the lamina to one another1 and to the amount of curvature of the whole pinnule4 ,unless the material is abundant1 it is often impossible to distinguish between characters of specific value and others which are the expression of differences in age or of position on a large frond1 to say nothing of the well-known variability which is amply illustrated by recent ferns4 ,it is remarkable that very few specimens are known which throw any light on the nature of the fertile pinnae4 ,fig4 #beh represents an impression from the ,inferior ,oolite rocks of the ,yorkshire coast in which the exposed upper surface of the pinnules shows a series of parallel ridges following the course of the lateral veins and no doubt formed by oblong sori on the lower surface4 ,there can be little doubt that the specimen figured by ,lindley and ,hutton and by others as ,pecopteris undans#hag is1 as ,nathorst suggests1 a portion of a fertile frond of ,c4 denticulata4 ,a fertile specimen of a frond resembling in habit ,c4 denticulata1 which ,fontaine has described from the ,jurassic rocks of ,oregon as ,danaeopsis ,storrsii#hah1 exhibits1 as that author points out1 a superficial resemblance to the specimen named by ,lindley and ,hutton ,pecopteris undans4 ,there is1 however1 no adequate reason for referring the ,american fragment to the ,marattiaceae4 ,in the absence of sporangia we cannot speak confidently as to the systematic position of this common type2 but there are fairly good grounds for the assertion that some at least of the fronds described under this name are those of ,osmundaceae4 ,the ,english specimen shown in fig4 #beh is very similar to some ,indian fossils figured by ,feistmantel as ,asplenites macrocarpus#hai1 which are probably identical with ,pecopteris australis ,morris#hbj1 a fern that is indistinguishable from ,cladophlebis denticulata4 ,renault#hba figured a fertile specimen of the ,australian fossil as ,todea australis1 which agrees very closely with that shown in fig4 #beh1 and the sporangia figured by the ,french author are of the ,osmundaceous type4 ,another example of a fertile specimen is afforded by a ,rhaetic fern from ,franconia1 ,asplenites ottonis1 which is probably identical with ,alethopteris ,roesserti ,presl ,cladophlebis 7,todites7 ,roesserti1 a plant closely resembling ,cladophlebis denticulata4 ,another argument in favour of including ,c4 denticulata in the ,osmundaceae is supplied by the association of pinnae of this type with the petrified stem of ,osmundites ,dunlopi recorded by ,kidston and ,gwynne-,vaughan4 ,illustration3 ,,fig4 #beh4 ,fertile pinnae of ,cladophlebis denticulata4 7,from a ,yorkshire specimen in the ,sedgwick ,museum1 ,cambridge47 ,schizaeaceae4 ,evidence bearing on the existence of this family in ,carboniferous floras is by no means decisive4 ,the generic name ,aneimites proposed by ,dawson#hbb for some ,devonian ,canadian plants resembling species of the recent genus ,aneimia1 and adopted by ,white#hbc for a species from the ,pottsville beds of ,virginia1 is misleading4 ,the ,canadian plants give no indication of the nature of the reproductive organs1 and the fronds described by ,white are1 as he shows1 those of a ,pteridosperm and bore seeds4 ,an examination of the suspiciously diagrammatic drawings published by ,corda#hbd of the small fertile pinnules of a ,carboniferous fern from ,bohemia1 which he named ,senftenbergia elegans1 leads us to conclude that the sporangia are almost certainly those of a ,schizaeaceous species4 ,the small linear pinnules bear two rows of sessile sporangia1 singly as in recent ,schizaeaceae and not in sori1 characterised by #d-e rows of regular annular cells 7fig4 #bgj1 ,a7 surrounding the apex4 ,it has already been pointed out that the apical annulus of recent ,schizaeaceae1 though normally one row deep1 may consist in part at least of two rows4 ,zeiller#hbe examined specimens of ,corda's species and decided in favour of a ,schizaeaceous affinity2 he describes the sporangia as #jhe-jie mm4 in length1 with #c to #e and occasionally only two rows of cells in the apical annulus4 ,zeiller's figures 7fig4 #bgj1 ,a7 confirm the impression that ,corda's drawings are more beautiful than accurate4 ,stur#hbf1 on the other hand1 who first pointed out that the type-specimens of ,senftenbergia came from the ,radnitz beds of ,bohemia and not from the ,coal-,measures1 convinced himself that the sporangia have no true annulus 7fig4 #bgj1 ,e74 ,he describes them as characterised by a comparatively strong wall and by the presence of a band of narrow vertical cells marking the line of dehiscence1 features which lead him to assign the plant to the ,marattiales1 a group which seems to have exercised a dominating influence over his judgment4 ,in a later publication ,zeiller#hbg replies to ,stur's criticism but adheres to his original opinion4 ,solms-,laubach#hbh1 while expressing himself in favour of ,marattiaceous affinity1 recognises that ,zeiller's arguments cannot be set aside4 ,the question must remain open until further evidence is forthcoming2 but it would seem that this ,carboniferous type1 not as yet recognised in ,britain1 possessed sporangia having a distinct resemblance to those of the ,schizaeaceae1 though this similarity does not amount to proof of the existence of the family in the ,palaeozoic era4 ,palaeozoic floras may be described as rich in generalised types1 types foreshadowing lines of evolution1 which in the course of ages led to a sorting and a redistribution of characters4 ,it may be that ,senftenbergia is one of these generalised types4 ,it is not until we ascend the geological series as far as the older ,jurassic rocks that we meet with a type which can with confidence be classed with the ,schizaeaceae1 as least so far as sporangial characters are concerned4 ,the species ,klukia exilis is selected as the best known and most widely-spread representative of ,jurassic ,schizaeaceae4 ,klukia exilis 7,phillips7#hbi4 ,fig4 #bei4 ,the generic name ,klukia was proposed by ,raciborski#hcj for a species originally described by ,phillips#hca from the ,inferior ,oolite of the ,yorkshire coast as ,pecopteris exilis4 ,bunbury's#hcb discovery 7supplemented by additional evidence obtained by ,raciborski7 of well-preserved sporangia justified the substitution of a distinctive designation for the provisional term ,pecopteris4 ,illustration3 ,,fig4 #bei4 ,klukia exilis 7,phillips74 7,figs4 #a-c1 #dj2 fig4 #d1 #c2 fig4 #e1 nat4 size47 ,the species may be defined as follows3-- ,frond tripinnate1 of the ,cladophlebis type2 pinnae linear1 lanceolate1 attached to the rachis at a wide angle4 ,ultimate segments short and linear1 entire or1 in the lower part of a frond1 crenulate1 #e mm4 long or occasionally longer4 ,sporangia #je mm4 in length1 borne singly on the lower surface of the lamina in a row on each side of the midrib4 ,a re-examination#hcc of the specimen described by ,bunbury confirmed his account of the structure of the sporangia4 ,the pinna shown in fig4 #bei is characterised by unusually small fertile pinnules some of which bear #aj sporangia in two rows2 the annulus includes about #ad cells4 ,fertile specimens of this and similar forms are figured by ,raciborski#hcd from ,jurassic rocks of ,poland1 and good examples of the ,english species may be seen in the ,leckenby collection1 ,cambridge1 in the ,british ,museum1 the museums of ,manchester1 ,scarborough1 and other places4 ,it is possible that specimens referred to ,k4 exilis by ,yokoyama#hce from ,wealden strata in ,japan may afford evidence of the persistence of the species beyond the ,jurassic era1 but in view of the close resemblance of the sterile fronds described from ,wealden strata as ,cladophlebis ,brownii#hcf and ,c4 ,dunkeri#hcf to those of ,klukia exilis1 identity can be established only by an examination of fertile specimens4 ,a ,jurassic fern recently described by ,yabe#hcg from ,korea as ,cladophlebis koraiensis may be identical with ,k4 exilis and there is little doubt as to the existence of the species in ,jurassic ,caucasian strata#hch4 ,illustration3 ,,fig4 #bfj4 ,ruffordia ,goepperti4 7,a1 ,c1 sterile2 ,b1 fertile2 slightly reduced4 ,specimens from the ,wealden of ,sussex2 ,british ,museum2 ,v4 #bccc1 ,v4 #bafj1 ,v4 #baff47 ,ruffordia ,goepperti 7,dunk474 ,fig4 #bfj4 ,this ,wealden fern#hci has been doubtfully assigned to the ,schizaeaceae on the ground of the resemblance of the sterile fronds to those of some species of ,aneimia1 and because of the difference between the sterile and fertile pinnae 7,fig4 #bfj74 ,ruffordia cannot be regarded as a well authenticated member of the ,schizaeaceae4 ,illustration3 ,,fig4 #bfa4 ,a1 ,a4 ,chrysodium lanzaeanum4 ,b1 ,b4 ,lygodium ,kaulfussi4 ,c4 ,marattia ,hookeri4 7,after ,gardner and ,ettingshausen2 ,a1 ,b1 nat4 size47 ,lygodium ,kaulfussi1 ,heer4 ,fig4 #bfa1 ,b1 ,b4 ,fragments of forked pinnules1 agreeing very closely in venation and general appearance with recent species of ,lygodium1 have been identified by ,gardner and ,ettingshausen#hdj from ,english ,eocene beds and by ,knowlton from the ,miocene beds of the ,yellowstone ,park#hda as ,lygodium ,kaulfussi ,heer 7fig4 #bfa1 ,b74 ,despite the absence of sporangia it is probable that these fragments are correctly referred to the ,schizaeaceae4 ,the sterile and fertile specimens figured by ,heer#hdb from ,tertiary beds of ,switzerland agree very closely with recent examples of ,lygodium4 ,similar though perhaps less convincing evidence of the existence of this family in ,europe is furnished by ,saporta#hdc1 who described two ,eocene species from ,france4 ,gleicheniaceae4 ,the application by ,goeppert#hdd and other earlier writers of the generic name ,gleichenites to examples of ,palaeozoic ferns was not justified by any satisfactory evidence4 ,one of ,goeppert's species1 ,gleichenites neuropteroides1 is identical with ,neuropteris heterophylla#hde1 a plant now included in the ,pteridosperms4 ,the resemblance of sporangia and sori1 whether preserved as carbonised impressions or as petrified material1 from ,carboniferous rocks1 to those of recent species of ,gleicheniaceae is in many cases at least the result of misinterpretation of deceptive appearances4 ,williamson#hdf drew attention to the ,gleichenia-like structure of some sections of sporangia from the ,english ,coal-,measures1 but he did not realise the ease with which sections of ,marattiaceous sporangia in different planes may be mistaken for those of annulate 7leptosporangiate7 sporangia4 ,in the regular dichotomous habit of ,carboniferous fronds described as species of ,diplothmema 7,stur7 and ,mariopteris 7,zeiller7#hdg we have a close correspondence with the leaves of ,gleichenia1 but the common occurrence of dichotomous branching among ferns is sufficient reason for regarding this feature as an untrustworthy criterion of relationship4 ,it is1 however1 interesting to find that in addition to the existence of some ,upper ,carboniferous ferns with sori like those of recent ,gleichenias1 the type of stelar anatomy illustrated by ,gleichenia dicarpa 7fig4 #bcg1 ,c1 p4 #caj7 and other species is characteristic of the primary structure of the stem of the ,pteridosperm ,heterangium4 ,we find in ,carboniferous types undoubted indications of anatomical and other features which in succeeding ages became the marks of ,gleicheniaceae4 ,some ,carboniferous fronds with short and small pinnules of the ,pecopteris type1 bearing sori composed of a small number of sporangia1 have been assigned by ,grand',eury and other authors to the ,gleicheniaceae2 the same form of sorus is met with also on fronds with ,sphenopteroid segments4 ,the former is illustrated by ,oligocarpia ,gutbieri#hdh and the latter by ,o4 ,brongniarti described by ,stur and by ,zeiller#hdi4 ,zeiller has described the circular sori of ,oligocarpia 7fig4 #bgj1 ,b7 as consisting of three to ten pyriform sporangia borne at the ends of lateral veins and possessing a complete transverse annulus1 but ,stur#hej believes that the annulus-like appearance is due to the manner of preservation of exannulate sporangia4 ,in this opinion ,stur is supported by ,solms-,laubach#hea and by ,schenk#heb4 ,despite an agreement between ,oligocarpia and ,gleichenia1 as regards the form of the sori and the number of sporangia1 it is not certain that the existence of a typical ,gleicheniaceous annulus has been proved to occur in any ,palaeozoic sporangia#hec4 ,from ,upper ,triassic beds of ,virginia1 ,fontaine has figured several fronds for which he instituted the genus ,mertensides#hed4 ,the habit1 as he points out1 is not dichotomous1 but the sori are circular and are said to be composed in some species of four to six sporangia4 ,no satisfactory evidence is brought forward in support of the use of a designation implying a close relationship with recent ,gleichenias 7sect4 ,mertensia74 ,one of the species described by ,fontaine was originally named by ,bunbury ,pecopteris bullatus#hee1 the imperfect type-specimen of which is now in the ,museum of the ,cambridge ,botany ,school4 ,in the form of the frond1 the thick rachis1 and in the pinnules this ,triassic species resembles ,todites ,williamsoni1 but the resemblance does not extend to the sori4 ,two of ,fontaine's species are recorded by ,stur from ,austria#hef1 but he places them in the genus ,oligocarpia and includes them in the ,marattiaceae4 ,leuthardt#heg figures what appears to be a ,gleicheniaceous fern from the ,upper ,triassic beds of ,basel as ,gleichenites gracilis 7,heer7 showing sori composed of five sporangia 7fig4 #bfe1 ,c7 with a horizontal annulus4 ,a ,rhaetic species ,gleichenites microphyllus ,schenk#heh from ,franconia agrees in the form of its small rounded pinnules with ,gleichenia1 but no sporangia have so far been found4 ,an impression of a frond from ,jurassic rocks of northern ,italy figured by ,zigno as ,gleichenites elegans#hei closely resembles in habit recent species of ,gleichenia2 though no sporangia have been found1 the habit of the frond gives probability to ,zigno's determination4 ,a ,jurassic species from ,poland1 ,gleichenites ,rostafinskii1 referred by ,raciborski#hfj to ,gleichenia1 exhibits a close agreement in habit and in the form of the soral impressions to some recent species of ,gleichenia4 ,as we pass upwards to ,wealden and more recent rocks it becomes clear that the ,gleicheniaceae were prominent members of late ,mesozoic floras in north ,europe and reached as far north as ,disco ,island4 ,in ,english ,wealden beds portions of sterile fronds have been found which were assigned to a new genus ,leckenbya#hfa1 but it is probable that these specimens would be more correctly referred to ,gleichenites4 ,similarly fragments of ,gleichenia-like pinnae with very small rounded pinnules occur in the ,wealden rocks of ,bernissart1 ,belgium#hfb1 in north ,germany#hfc1 and elsewhere4 ,conclusive evidence has been obtained by ,prof4 ,bommer of the existence of ,gleichenites in ,wealden beds near ,brussels1 where many plant remains have been found in a wonderful state of preservation4 ,the specimens1 which ,i had an opportunity of seeing some years ago1 might easily be mistaken for rather old and brown pieces of recent plants4 ,some of the ,belgian fragments1 of which ,prof4 ,bommer has kindly sent me drawings and photographs1 are characterised by an arrangement of vascular tissue identical with that in the petioles and rhizomes of some protostelic ,gleichenias4 ,the stele of one of the ,belgian rhizomes appears to be identical with that of ,gleichenia dicarpa 7fig4 #bcg1 ,c4 p4 #caj74 ,illustration3 ,,fig4 #bfb4 ,a4 ,gleichenites longipennis ,heer4 ,b4 ,g4 delicatula ,heer4 ,c4 ,g4 ,nordenskioldi ,heer4 ,d4 ,g4 ,zippei4 7,corda47 7,after ,heer2 ,a1 ,b1 ,d1 very slightly reduced47 ,gleichenites ,zippei 7,corda74 ,fig4 #bfb1 ,d4 ,this species1 originally described by ,corda as ,pecopteris ,zippei#hfd and afterwards figured by ,heer#hfe as ,gleichenia ,zippei 7fig4 #bfb1 ,d7 from ,urgonian rocks of ,greenland1 affords a striking example of a ,mesozoic member of the ,gleicheniaceae4 ,it is characterised by the dichotomous branching of the frond and by the occurrence of arrested buds in the forks4 ,the long and slender pinnae1 reaching a length of #i cm4 and a breadth of #f-h mm41 bear small crowded pinnules occasionally with circular sori which are described by ,heer as consisting of a small number of sporangia 7cf4 fig4 #bfb1 ,c74 ,several other ,lower ,cretaceous species are recorded by ,heer from ,greenland1 some of which are probably unnecessarily separated from ,gleichenites ,zippei4 ,examples of these are represented in fig4 #bfb1 ,a1 ,b1 ,c4 ,a ,gleicheniaceous species described by ,debey and ,ettingshausen from ,lower ,cretaceous rocks of ,aix-la-,chapelle as ,didymosorus comptonifolius#hff is very similar in habit to some of ,heer's ,greenland species3 this should probably be referred to the genus ,gleichenites4 ,gleichenites hantonensis1 ,wank4 ,fig4 #bfc4 ,from the ,eocene beds of ,bournemouth1 ,gardner and ,ettingshausen#hfg have described under the name ,gleichenia hantonensis what is in all probability a true ,gleichenia 7fig4 #bfc74 ,this species1 originally recorded by ,wanklyn#hfh1 is characterised by a slender forked rachis showing what may be traces of arrested buds between the arms of the branches1 by circular sori of six or eight sporangia and by the presence of peculiar tendril-like appendages on the pinnae4 ,if the description of the tendrils is correct1 this ,british species affords one of the few instances of ferns adapted for climbing and may be compared with the recent species ,davallia aculeata 7fig4 #bcb1 p4 #bii74 ,matonineae4 ,the genera ,laccopteris and ,matonidium may be described as examples of ,mesozoic ferns exhibiting a very close agreement with ,matonia4 ,laccopteris4 ,this genus1 founded by ,presl#hfi1 may be described as follows3-- ,frond pedate1 in habit resembling ,matonia pectinata1 with pinnate or pinnatifid pinnae2 ultimate segments linear1 provided with a well-marked midrib giving off numerous dichotomously branched secondary veins which are in places connected by lateral anastomoses4 ,sori circular1 forming a single row on each side of the midrib 7fig4 #bgh1 ,b72 sporangia #e-ae in each sorus1 with an oblique annulus and tetrahedral spores4 ,the presence of an indusium is not certainly established4 ,illustration3 ,,fig4 #bfc4 ,gleichenites hantonensis ,wank4 7,restoration1 after ,gardner and ,ettingshausen47 ,schenk#hgj1 who described several specimens of ,laccopteris from ,rhaetic rocks of ,germany1 compared the genus with ,gleichenia but he also recognised the close resemblance to ,matonia pectinata4 ,zeiller#hga first established the practical identity of the sori and sporangia of ,laccopteris and ,matonia4 ,the ,rhaetic species1 such as ,l4 ,muensteri1 ,l4 elegans1 and ,l4 ,goepperti1 agree very closely with ,l4 polypodioides and need not be described in detail4 ,illustration3 ,,fig4 #bfd4 ,laccopteris elegans 7,presl74 7,from a specimen in the ,british ,museum2 from the ,lower ,keuper of ,bayreuth1 ,germany4 ,nat4 size2 part of pinnule #c47 ,the ,rhaetic species ,laccopteris elegans1 represented in fig4 #bfd1 illustrates the characteristic habit of the genus and shows a feature usually overlooked#hgb1 namely the occurrence of anastomoses between the lateral veins4 ,the form of the sorus of another ,rhaetic species is shown in fig4 #bfe1 ,e4 ,schenk figures an interesting series of fronds of ,l4 ,goepperti in different stages of growth#hgc2 one of the younger leaves is seen in fig4 #bfe1 ,d4 ,an examination of ,rhaetic specimens of ,laccopteris in the ,bergakademie of ,berlin convinced me of the correctness of the published descriptions of the sori4 ,illustration3 ,,fig4 #bfe4 ,a4 ,matonidium ,wiesneri4 7,slightly enlarged47 ,b4 ,marattiopsis marantacea4 7,slightly enlarged47 ,c4 ,gleichenites gracilis4 7,slightly enlarged47 ,d4 ,laccopteris ,goepperti4 7,slightly reduced47 ,e4 ,l4 ,muensteri4 7,enlarged47 7,a1 after ,krasser2 ,b1 ,c1 after ,leuthardt2 ,d1 ,e1 after ,schenk47 ,laccopteris polypodioides 7,brongniart74 ,figs4 #bff-bfh2 #bgh1 ,a4 #ahbh4 ,phlebopteris polypodioides#hgd1 ,brongniart1 ,hist4 vg4 foss4 p4 #cgb1 ,pl4 ,,lxxxiii4 fig4 #a4 -- ,p4 propinqua1 ibid4 ,pls4 ,,cxxxii4 fig4 #a1 ,,cxxxiii4 fig4 #b4 #ahbi4 ,pecopteris caespitosa1 ,phillips1 ,geol4 ,yorks4 p4 #adh1 ,pl4 ,,viii4 fig4 #aj4 -- ,p4 crenifolia1 ibid4 ,pl4 ,,viii4 fig4 #aj4 -- ,p4 ligata1 ibid4 ,pl4 ,,viii4 fig4 #ad4 ,illustration3 ,,fig4 #bff4 ,laccopteris polypodioides 7,brongn474 7 #ad47 7,brit4 ,mus47 ,in habit this species closely resembles ,matonia and ,matonidium1 the long petiole divides distally into several spreading pinnatifid pinnae with linear ultimate segments 7fig4 #bgh1 ,a74 ,circular sori 7indusiate87 occur in a single row on each side of the midrib containing #ab-ad large sporangia 7fig4 #bff7 characterised by an obliquely vertical annulus4 ,the midrib of the pinnules gives off secondary veins at a wide angle and these form a series of elongated meshes parallel to the median rib1 as in the recent genus ,woodwardia2 forked and anastomosing branches are given off from these to the edge of the lamina 7fig4 #bfg74 ,illustration3 ,,fig4 #bfg4 ,pinnules of ,laccopteris4 7,enlarged47 ,a1 ,b4 ,from the ,inferior ,oolite of ,yorkshire4 ,c4 ,from the ,inferior ,oolite of ,stamford4 7,british ,museum47 ,the specimen shown in fig4 #bfh is probably a young frond of this species4 ,a very similar1 possibly a specifically identical plant1 was described by ,leckenby from ,english ,jurassic rocks as ,phlebopteris ,woodwardi#hge1 the distinguishing features of which are the greater number of lateral veins and the smaller sori 7fig4 #bfg1 ,a74 ,the name ,microdictyon was proposed by ,saporta#hgf for pinnules differing slightly from those of ,laccopteris in venation characters3 he included ,laccopteris ,woodwardi in this genus1 but such differences as are recognisable in the venation hardly justify the use of a distinct generic title4 ,similarly1 specimens described by ,debey and ,ettingshausen#hgg from ,lower ,cretaceous rocks of ,aix-la-,chapelle as species of ,carolopteris may also be included in ,laccopteris4 ,illustration3 ,,fig4 #bfh4 8 ,laccopteris polypodioides4 ,nat4 size4 ,from a specimen in the ,whitby ,museum 7,brit4 ,mus474 ,laccopteris ,dunkeri 7,schenk7#hgh4 ,this species is represented in several ,wealden localities by fragments of fertile pinnae similar to those of ,l4 polypodioides4 ,it is almost impossible to distinguish small specimens of the ,wealden fern from ,heer's genus ,nathorstia 7,marattiaceae7 unless the sori are well preserved4 ,this species occurs in ,wealden beds in ,england1 ,germany1 ,belgium1 and elsewhere and has been discovered by ,dr ,marcus ,gunn in ,upper ,jurassic plant-beds of ,sutherlandshire 7,n4,e4 ,scotland74 ,laccopteris is widely spread in ,rhaetic1 ,jurassic and ,lower ,cretaceous floras4 ,it affords evidence of the former abundance in northern latitudes of a family now represented by the two species of ,matonia confined to a restricted area in the southern hemisphere4 ,matonidium4 ,schenk#hgi instituted this convenient term for fossil fern fronds agreeing in habit and in their sori with ,matonia pectinata 7figs4 #bbg1 #bbh1 p4 #bib74 ,zeiller#hhj has drawn attention to the fact that the ,mesozoic species differ from the surviving types in the greater number of sporangia in each sorus1 and1 it may be added1 in ,matonidium the fertile pinnules are more richly supplied with sori than are those of ,matonia4 ,unfortunately our knowledge of the structure of the sporangia of ,matonidium is less complete than in the case of ,laccopteris1 but such evidence as is available justifies the conclusion that ,matonia is a direct descendant of ferns which formed a prominent feature in ,european ,jurassic and ,wealden floras4 ,it is interesting to find that in a ,cretaceous species1 described by ,krasser 7fig4 #bfe1 ,a7 since the publication of ,zeiller's paper1 the sori appear to be identical in distribution and in appearance with those of the recent species4 ,i am indebted to ,prof4 ,bommer for permission to reproduce the unpublished drawing represented in fig4 #bcg ,d 7p4 #caj7 of a section of the rhizome of ,matonidium from the ,belgian ,wealden beds of ,hainaut 78,flore ,bernissartienne074 ,the section shows an arrangement of vascular tissue identical with that in the recent species3 there may be two solenosteles and in addition a solid axial strand4 ,the form of the leaf-trace in the fossil appears to be identical with that in ,matonia pectinata 7fig4 #bcg1 ,a1 p4 #caj74 ,matonidium ,goepperti 7,ettingshausen7#hha4 ,fig4 #bfi4 ,under this name are included specimens from ,inferior ,oolite and ,wealden strata in ,britain and elsewhere4 ,it is1 however1 not impossible that if more information were available1 we should find adequate reasons for recognising two specific types4 ,fontaine#hhb1 adhering rigidly to the rules of priority1 speaks of this species as ,matonidium ,althausii 7,dunker71 but ,ettingshausen's specific term is better known4 ,illustration3 ,,fig4 #bfi4 ,matonidium ,goepperti 7,ettings474 7,a1 ,b1 nat4 size2 ,c1 approximately nat4 size47 ,fronds pedate and apparently identical in habit with those of ,matonia pectinata2 ultimate segments linear1 slightly falcate and bluntly pointed4 ,sori circular or oval1 numerous1 containing #ae to #bj sporangia with an oblique annulus1 in two rows on the lower surface of the pinnules2 indusium as in ,matonia4 ,the ,english examples have so far afforded no information in regard to sporangial structure1 but ,schenk#hhc has recognised a distinct annulus in ,german material4 ,in his description of fossil plants from ,lower ,cretaceous rocks in ,california1 ,fontaine#hhd doubtfully identifies two very small fragments as ,matonidium ,althausii2 the evidence is1 however1 wholly inadequate4 ,matonidium ,wiesneri1 ,krasser#hhe4 ,fig4 #bfe1 ,a4 ,this ,cenomanian 7,cretaceous7 species from ,moravia appears to be identical in habit with the older type4 ,the pinnules are larger and bear fewer sori4 ,krasser's figures of the sterile pinnules show no lateral anastomosing between the secondary veins1 but the small vascular network below each sorus 7fig4 #bfe1 ,a7 is identical with that in ,matonia pectinata4 ,the indusiate sori contain about six sporangia with an oblique annulus4 ,the very wide geographical distribution of the ,matonineae during the ,mesozoic era affords a striking contrast to the limited range of the ,malayan survivals4 ,hymenophyllaceae4 ,the frequent use of the generic name ,hymenophyllites as a designation of ,palaeozoic ferns1 more particularly in the older literature1 is another instance of the undue importance which palaeobotanists have always been prone to attach to external resemblances of vegetative organs4 ,the fragment of lamina described by ,stur for the ,culm ,measures of ,austria as ,hymenophyllum waldenburgense#hhf has no claim to consideration as evidence of ,palaeozoic ,hymenophyllaceae4 ,on the other hand1 there are a few records of fertile fronds which1 though not to be accepted without reserve1 are worthy of more careful examination4 ,some petrified sporangia described by ,renault#hhg from the ,culm of ,esnost are referred to ,hymenophyllites on account of the position of the annulus1 which appears to encircle about two-thirds of the circumference2 it is1 however1 not certain that the annulus is horizontal as in the recent genus4 ,the ,culm species ,rhodea patentissima described by ,ettingshausen#hhh as ,hymenophyllites patentissima and subsequently referred by ,stur#hhi to ,rhodea1 is regarded by these authors as closely allied to ,hymenophyllum simply on the ground of the finely divided and delicate sterile fronds2 another species1 ,rhodea moravica 7,ett471 which ,ettingshausen referred to ,trichomanes1 is compared with recent species of that genus4 ,in neither case do we know anything of sporangial characters4 ,illustration3 ,,fig4 #bgj4 ,a1 ,e4 ,senftenbergia elegans4 ,b4 ,oligocarpia ,brongniartii4 ,c4 ,trichomanes sp4 ,d4 ,hymenophyllum tunbrigense4 ,f1 ,g4 ,sphenopteris 7,hymenophyllites7 quadridactylites4 7,a1 ,b1 ,f1 ,g1 after ,zeiller2 ,d1 after ,hooker2 ,e1 after ,stur47 ,a fertile sphenopteroid frond figured by ,schimper as ,hymenophyllum ,weissi#hij from the ,coal-,measures of ,saarbrcken bears some resemblance to recent ,hymenophyllaceae1 but the figures are by no means convincing3 an examination of the type-specimens in the ,strassburg ,museum led ,solms-,laubach#hia to express dissent from ,schimper's determination4 ,a more satisfactory example is that afforded by the fertile pieces of a frond described by ,zeiller#hib from ,french ,coal-,measures as ,hymenophyllites quadridactylites 7,gutbier74 ,some of the ultimate segments with a truncated tip are preserved in close association with a group of oval sporangia with a complete transverse annulus 7fig4 #bgj1 ,f1 ,g74 ,the position of the sporangia is such as to suggest their separation from a terminal columnar receptacle like that in ,trichomanes and ,hymenophyllum4 ,in his account of this species from the ,coal-,measures of the ,forest of ,wyre1 ,kidston#hic states that ,zeiller informed him that he had noticed traces of what appeared to be a columnar receptacle in the ,french specimens4 ,the records of ,hymenophyllaceae from the ,mesozoic and ,tertiary formations are not such as need detain us4 ,the facts bearing on the geological history of this family are singularly meagre4 ,there is no evidence which can be adduced in favour of regarding the ,hymenophyllaceae as ferns of great antiquity1 which played a prominent part in the floras of the past4 ,it is interesting to find that the genus ,ankyropteris#hid1 one of the ,botryopterideae 7a group of ,palaeozoic ,ferns for which ,i propose the name ,coenopterideae71 has a morphological character in common with ,trichomanes1 namely the production of axillary buds3 there are also features in the stelar anatomy shared by the ,botryopterideae and ,hymenophyllaceae#hie4 ,these resemblances1 though by no means amounting to proof of near relationship1 point to a remote ancestry for certain features retained by existing members of the ,hymenophyllaceae4 ,cyatheaceae4 ,the specimens from the ,culm rocks of ,moravia on which ,stur founded the species ,thyrsopteris schistorum#hif are too imperfectly preserved to warrant the use of this generic name4 ,goeppert#hig in #ahcf instituted the genera ,cyatheites1 ,hemitelites1 and ,balantites for species of ,carboniferous ferns believed to be closely allied to recent ,cyatheaceae1 but a fuller knowledge of these types has clearly demonstrated that in all cases the reference to this family had no justification4 ,the ,upper ,carboniferous species ,dicksonites ,pluckeneti1 of which ,sterzel#hih described fertile specimens in #ahhf as possessing circular sori1 has since been shown by ,grand',eury#hii to be a ,pteridosperm bearing small seeds4 ,in ,sphenopteris 7,discopteris7 cristata 7,brongn47 ,zeiller#ijj has described sori very like those of ,cyathea and ,alsophila1 but differing in the exannulate sporangia3 this species1 like so many of the ,palaeozoic ferns1 is probably more akin to the ,marattiaceae than to the ,cyatheaceae4 ,we have as yet no satisfactory evidence of the existence of the ,cyatheaceae in ,palaeozoic floras4 ,it is not until we reach the ,jurassic period that trustworthy data are obtained4 ,raciborski#ija has identified as ,cyatheaceous fertile ,jurassic fronds from ,poland1 but his figures are inconclusive4 ,in ,alsophila polonica it is not clear whether the annulus is vertical or oblique1 and in another supposed member of the family1 ,gonatosorus ,nathorsti1 in which the indusium is described as bivalvate1 there is no proof of affinity to ,cyatheaceae4 ,in attempting to decipher the past history of the ,cyatheaceae it is important to remember the close resemblance between the fertile segments of some species of ,davallia 7,polypodiaceae7 and those of ,dicksonia 7fig4 #bbi1 ,c1 ,d1 p4 #bid74 ,unless the sporangia are well enough preserved to show the position of the annulus1 it is frequently impossible to feel much confidence in the value of the grosser features1 such as the reduced lamina of the fertile segments and the form of the sori4 ,it is1 however1 probable that the widely-spread ,jurassic species ,coniopteris hymenophylloides is correctly referred to the ,cyatheaceae1 but even in the case of this species the evidence of external form needs confirmation by an examination of individual sporangia4 ,coniopteris4 ,this genus was instituted by ,brongniart#ijb for fossil fronds characterised by pinnules more or less intermediate between the ,pecopteris and ,sphenopteris type and agreeing in the form of the sori with the leaves of recent species of ,dicksonia4 ,it should be noted that ,stur included in this genus a species1 ,coniopteris lunzensis#ijc from the ,upper ,trias of ,lunz1 which he regarded as a ,marattiaceous fern4 ,coniopteris hymenophylloides1 ,brongn4 ,figs4 #bga1 #bgb1 #bge1 ,b4 #ahbh4 ,sphenopteris hymenophylloides1 ,brongniart1 ,hist4 vg4 foss4 p4 #ahi1 ,pl4 ,,lvi4 fig4 #d4 #ahbi4 ,s4 stipata1 ,phillips1 ,geol4 ,york4 p4 #adg1 ,pl4 ,x4 fig4 #h4 #ahce4 ,tympanophora simplex1 ,lindley and ,hutton1 ,foss4 ,flor4 ,pl4 ,,clxx4 ,a4 -- ,t4 racemosa1 ibid4 ,pl4 ,,clxx4 ,b4 -- ,sphenopteris arguta1 ibid4 ,pl4 ,,clxviii4 #ahcf4 ,hymenophyllites ,phillipsi1 ,goeppert1 ,foss4 ,farn4 p4 #bef4 #ahdi4 ,coniopteris hymenophylloides1 ,brongniart1 ,tableau1 p4 #aje4 -- ,coniopteris ,murrayana1 ibid4 #ahea4 ,sphenopteris nephrocarpa1 ,bunbury1 ,quart4 ,journ4 ,geol4 ,soc4 ,vol4 ,,vii4 p4 #abi1 ,pl4 ,,xii4 fig4 #a4 #ahgf4 ,thyrsopteris ,murrayana1 ,heer1 ,flor4 ,foss4 ,arct4 ,vol4 ,,iv4 7#b7 p4 #cj1 ,pls4 ,i4 ,,ii4 ,,viii4 ,the above list represents a small selection of the names applied to ,jurassic ferns from different localities which there are good grounds for regarding as referable to a single type#ijd4 ,frond tripinnate2 pinnae linear acuminate1 attached to the rachis at a wide angle2 the pinnules vary considerably in size and shape2 in some the lamina is divided into a few broad and rounded lobes 7fig4 #bge1 ,b7 while in others the leaflets are dissected into narrow linear segments4 ,the sori are borne at the ends of veins2 the fertile pinnules have a much reduced lamina and1 in extreme cases1 bear a close resemblance to those of ,thyrsopteris elegans 7fig4 #bbi1 ,a1 p4 #bid74 ,the sori are partially enclosed in a cup-like indusium and the sporangia appear to have an oblique annulus4 ,venation and habit of frond of the ,sphenopteris type4 ,illustration3 ,,fig4 #bga4 ,coniopteris hymenophylloides 7,brongn474 ,nat4 size4 ,from a specimen in the ,manchester ,museum4 ,the pinna shown in fig4 #bga is the type-specimen of ,sphenopteris arguta ,lind4 and ,hutt4 from the ,yorkshire ,inferior ,oolite and is indistinguishable from the ,english examples on which ,brongniart founded his species ,s4 hymenophylloides4 ,fig4 #bgb shows a specimen from the ,york ,museum illustrating the difference between the sterile and fertile pinnae4 ,the resemblance of some fertile pinnae of ,coniopteris hymenophylloides to those of ,thyrsopteris elegans has led to a frequent use1 without any solid justification1 of the generic name of the ,juan ,fernandez fern for ,jurassic and ,wealden plants4 ,it is not impossible that some of the fossils described by ,heer from ,jurassic rocks of ,siberia#ije as species of ,thyrsopteris are ,cyatheaceous ferns1 but it is impossible to say with certainty that they are generically identical with the recent species4 ,in his monograph of the ,potomac flora of ,virginia#ijf and ,maryland1 ,fontaine has described as species of ,thyrsopteris several specimens of fronds which afford no evidence as to the nature of the sori or sporangia4 ,some of the fronds referred by this author to ,thyrsopteris rarinervis#ijg1 which ,i examined in the ,washington ,museum1 are in all probability examples of ,onychiopsis1 a genus included in the ,polypodiaceae4 ,the fragments described by ,lester ,ward#ijh as species of ,thyrsopteris from the ,lower ,cretaceous of the ,black ,hills of ,north ,america afford no satisfactory evidence of relationship to the recent type4 ,similarly ,velenovsk has described a ,lower ,cretaceous ,onychiopsis from ,bohemia#iji as a species of ,thyrsopteris1 although the fertile segments bear little or no resemblance to those of the ,cyatheaceous genus4 ,some fertile portions of fronds described by ,heer#iaj as ,asplenium ,johnstrupi and afterwards as ,dicksonia ,johnstrupi#iaa from the ,cretaceous beds 7,kome series7 of ,greenland are very similar to ,coniopteris hymenophylloides4 ,illustration3 ,,fig4 #bgb4 ,coniopteris hymenophylloides4 ,specimen from the ,inferior ,oolite1 ,scarborough2 in the ,york ,museum4 ,m4,s4 ,coniopteris quinqueloba 7,phillips74 ,fig4 #bgc4 ,this species1 originally described by ,phillips#iab as ,sphenopteris quinqueloba1 is very similar in habit to ,c4 hymenophylloides1 differing chiefly in the smaller size of the leaf and in the narrower ultimate segments4 ,the specimen shown in fig4 #bgc1 ,b1 illustrates the form of the sorus and sporangia4 ,illustration3 ,,fig4 #bgc4 ,coniopteris quinqueloba 7,phillips74 ,a1 #b2 ,b1 considerably enlarged4 ,from drawings supplied by ,dr ,nathorst4 ,coniopteris arguta 7,lind4 and ,hutt4#iac74 ,figs4 #bgd1 #bge1 ,a4 ,the sterile pinnae of this species bear pinnules of a type met with in various species of ferns from different horizons2 the smaller ones are entire and slightly falcate1 while on the lower part of a frond the ultimate segments are longer and have a crenulate margin4 ,the fertile pinnae bear pinnules reduced to a midrib with a narrow border1 and terminating in a cup-like indusium 7fig4 #bge1 ,a74 ,in habit the sterile leaf 7fig4 #bgd7 of this species is similar to the ,jurassic ,schizaeaceous fern ,klukia exilis4 ,protopteris4 ,presl#iad instituted this genus for a ,lower ,cretaceous tree-fern from ,bohemia originally figured as ,lepidodendron punctatum#iae and assigned to a ,palaeozoic horizon2 it was afterwards named by ,corda#iaf ,protopteris ,sternbergii and referred by ,brongniart#iag to ,sigillaria4 ,the genus ,protopteris stands for fossil fern-stems with the habit and1 in the main1 the structural features of recent tree-ferns4 ,persistent leaf-bases and sinuous adventitious roots cover the surface of the stems3 the vascular system is of the dictyostelic type characteristic of ,cyathea 7fig4 #bdj1 p4 #cac7 and ,alsophila4 ,it is by the pattern formed by the vascular tissue on the exposed surface of the leaf-bases that ,protopteris is most readily recognised3 the leaf-trace has a horse-shoe form with the ends curled inwards and the sides more or less indented 7fig4 #bgg74 ,the generic name ,caulopteris is used by some authors in preference to ,presl's genus2 but ,protopteris is more conveniently restricted to ,mesozoic ,cyatheaceous stems and ,caulopteris to ,palaeozoic stems1 with the internal structure of ,psaronius 7see ,chap4 ,,xxiii474 ,stenzel applies ,caulopteris to ,mesozoic stems in which the leaf-trace consists of several separate strands and not of a continuous band4 ,illustration3 ,,fig4 #bgd4 ,coniopteris arguta4 7,nat4 size4 ,from a specimen in the ,sedgwick ,museum1 ,cambridge47 ,illustration3 ,,fig4 #bge4 ,a4 ,coniopteris arguta4 7,fertile pinnae2 nat4 size47 ,b4 ,c4 hymenophylloides4 ,a1 from the ,inferior ,oolite of ,yorkshire 7,british ,museum72 ,b1 from ,jurassic rocks in ,turkestan4 ,lower ,cretaceous casts of tree-fern stems in the ,prague ,museum have been described under the names ,alsophilina and ,oncopteris2 the figures of the latter 7fig4 #bgf7 given by ,feistmantel#iah and by ,velenovsk#iai show the petiole-bases arranged in vertical rows and characterised by leaf-traces consisting of two separate strands in the form of two ,vs lying on their sides4 ,tree-fern stems described under various generic names are not infrequently found in ,european ,lower ,cretaceous rocks3 their comparative abundance affords an example of striking changes in geographical distribution since the latter part of the ,mesozoic epoch4 ,the ,cyatheaceae no longer exist in ,europe and the arborescent species of the genus have retreated to more southern regions4 ,illustration3 ,,fig4 #bgf4 ,oncopteris ,nettvalli4 7,after ,velenovsk2 nat4 size47 ,illustration3 ,,fig4 #bgg4 ,protopteris punctata4 7,after ,heer2 very slightly reduced47 ,protopteris punctata 7,sternb474 ,fig4 #bgg4 ,the earliest information in regard to the anatomy of this widely spread ,lower ,cretaceous fern we owe to ,corda1 who showed that the species agrees in essentials with existing tree-ferns4 ,the ,english example described by ,carruthers#ibj from ,upper ,greensand beds in ,dorsetshire 7now in the ,british ,museum7 shows only the external features4 ,the sandstone cast 7#ad cm4 in diameter71 of which a portion is seen in fig4 #bgg1 was described by ,heer from ,disco ,island 7,greenland7 as a ,carboniferous species#iba1 but afterwards correctly assigned to the ,cenomanian series#ibb ,this species is recorded also from the ,lower ,cretaceous of ,bohemia by ,fri and ,bayer#ibc ,among examples of petrified stems exhibiting a general agreement with ,protopteris punctata are those described by ,stenzel#ibd from ,turonian rocks in ,germany4 ,in one of these1 ,rhizodendron oppoliense ,gpp41 attention is drawn to branches given off from the stem stele which have a solenostelic structure in contrast to the dictyostele of the stem2 also to the minute structure of the tracheae which appear to have their ends perforated1 a feature shown by ,gwynne-,vaughan#ibe to be characteristic of the xylem elements of many ferns4 ,illustration3 ,,fig4 #bgh4 ,a4 ,laccopteris polypodioides1 ,brongn4 ,from a specimen 7#cibge7 in the ,british ,museum2 slightly reduced4 ,b4 ,l4 ,muensteri4 ,c4 ,dicksonia 7petiole stele74 ,d4 ,onychiopsis ,mantelli 7fertile segments74 ,e4 ,hausmannia ,sewardi ,richt4 ,f4 ,h4 ,kohlmanni ,bicht4 ,g1 ,h4 ,protopteris ,witteana1 ,schenk4 7x1 xylem2 ,r1 roots47 7,b1 after ,schenk2 ,e1 ,f1 after ,richter47 ,protopteris ,witteana ,schenk#ibf 7fig4 #bgh1 ,g1 ,h71 a ,wealden species recorded from ,germany and ,england1 represents a closely allied or possibly an identical type4 ,the section of the stem 7fig4 ,h7 shows the narrow vascular bands1 x1 of a dictyostele similar to that of recent ,cyatheaceous tree-ferns and a form of meristele 7fig4 ,g1 x7 resembling that of ,p4 punctata4 ,adventitious roots are seen in section at ,r 7figs4 ,g and ,h74 ,polypodiaceae4 ,sections of petrified sporangia from the ,english ,coal-,measures 7,pteridotheca sp47 occasionally exhibit a striking resemblance to those of recent ,polypodiaceae#ibg1 but in the absence of material in which it is possible to recognise the true orientation of the sporangia1 the exact position of the annulus is almost impossible to determine4 ,we have as yet no satisfactory evidence of the existence of true ,polypodiaceae in the ,palaeozoic era4 ,it is noteworthy that apart from the absence of ferns which can reasonably be included in this family1 the anatomical features of the ,botryopterideae 7,coenopterideae7 and of the ,cycadofilices or ,pteridosperms do not foreshadow those of ,polypodiaceous ferns4 ,on the other hand1 as we have already noticed1 anatomical characters of such families as the ,gleicheniaceae1 ,hymenophyllaceae1 and ,schizaeaceae are met with in certain generalised ,palaeozoic types4 ,these facts are perhaps of some importance as supplying collateral evidence in favour of the relatively more recent origin of the dominant family of ferns in modern floras4 ,illustration3 ,fig4 #bgi4 ,a4 ,adiantides antiques 7,ett474 7 nat4 size47 ,b4 ,a4 ,lindsayoides 7,sew474 7,b nat4 size47 7,a1 after ,kidston47 ,the use of the generic name ,adiantites for fern-like fronds of ,lower ,carboniferous age characterised by cuneate pinnules like those of species of ,adiantum1 suggests an affinity which is in all probability non-existent4 ,it has been pointed out that this generic name was applied in the first instance to the leaves of the ,jurassic plant ,ginkgo digitata#ibh and should1 therefore1 be discarded4 ,schimper#ibi used the designation ,adiantides1 and ,ettingshausen#icj1 more rashly than wisely1 preferred ,adiantum4 ,the specimens described by ,kidston#ica as ,adiantides antiquus 7,ett47 7fig4 #bgi1 ,a7 from the ,carboniferous limestone of ,flintshire are portions of tripinnate fronds bearing cuneate segments with numerous forked veins radiating from the contracted base of the lamina4 ,it is not improbable1 in view of ,dr ,white's#icb discovery of seeds on a very similar plant from the ,pottsville beds of ,north ,america1 that this characteristic ,lower ,carboniferous genus is a ,pteridosperm4 ,from ,jurassic rocks in various parts of the world numerous fossils have been described under the generic names ,aspidium1 ,asplenium1 ,davallia1 ,polypodium1 and ,pteris4 ,in the great majority of cases such records leave much to be desired from the point of view of students who appreciate the dangers of relying on external similarity between vegetative organs1 and on resemblances founded on obscure impressions of sori4 ,the generic term ,woodwardites#icc1 which suggests affinity with the recent genus ,woodwardia1 has been used for ,rhaetic plants belonging to the ,dipteridinae4 ,a plant described as ,adiantides ,lindsayoides from ,jurassic rocks of ,victoria#icd1 characterised by marginal sori which appear to be protected by the folded-over edge of the leaflets1 and by the resemblance of the pinnules to those of recent species of ,lindsaya1 may be a true ,polypodiaceous fern2 but in this case1 as in many similar instances1 nothing is known of the structure of the sporangia4 ,some sterile pinnae described by ,yabe from ,jurassic rocks of ,korea as ,adiantites ,sewardi#ice may perhaps be identical with the ,australian species4 ,in such a species as ,polypodium oregonense ,font41 from ,jurassic rocks of ,oregon1 the generic name is chosen because the 8fructification seems near enough to that of ,polypodium to justify the placing of the plant in that genus#icf40 ,but the fact that no sporangia have been found is a fatal objection to this identification4 ,onychiopsis4 ,this generic name was instituted by ,yokoyama#icg for a ,japanese ,wealden species1 previously described by ,geyler#ich as ,thyrsopteris elongata1 on the ground that1 in addition to a similarity in habit of the sterile fronds1 the fertile pinnae present a close agreement to those of the recent genus ,onychium4 ,onychiopsis ,mantelli#ici 7,brongn474 ,figs4 #bgh1 ,d2 #bhj1 ,a and ,b4 ,the ,japanese species ,onychiopsis elongata may perhaps be identical with this common ,wealden fern which1 as ,fontaine points out1 should be called ,o4 psilotoides if the rule of priority is to be observed irrespective of long usage4 #ahbd4 ,hymenopteris psilotoides1 ,stokes and ,webb1 ,trans4 ,geol4 ,soc4 ii41 ,vol4 ,i4 p4 #dbc1 ,pl4 ,,xlvi4 fig4 #g4 #ahbh4 ,sphenopteris ,mantelli1 ,brongniart1 ,hist4 vg4 foss4 p4 #agj1 ,pl4 ,,xlv4 figs4 #c-g4 #ahij4 ,onychiopsis ,mantelli1 ,nathorst1 ,denksch4 ,wien ,akad4 ,vol4 ,,lvii4 p4 #e4 ,onychiopsis ,mantelli may be defined as follows3-- ,frond bipinnate1 ovate lanceolate1 rachis winged2 pinnae approximate1 given off at an acute angle2 pinnules narrow1 acuminate1 with a single vein2 the larger segments serrate and gradually passing into pinnae with narrow ultimate segments4 ,fertile segments sessile or shortly stalked1 linear ovate1 sometimes terminating in a short awn-like prolongation4 ,the fertile segments 7fig4 #bgh1 ,d7 bear so close a resemblance to those of species of ,onychium that it would seem justifiable to regard the plant as a member of the ,polypodiaceae4 ,this fern is one of the most characteristic members of the ,wealden floras2 it occurs in abundance in the ,english ,wealden1 in ,portugal1 ,germany1 ,belgium1 ,japan1 ,bohemia1 ,south ,africa1 and elsewhere4 ,a piece of rhizome figured from the ,english ,wealden#idj is very similar to the creeping rhizomes of recent species of ,polypodiaceae4 ,the ,english ,wealden specimens shown in fig4 #bhj1 ,a and ,b1 illustrate the difference in form presented by leaves of this species2 the smaller pinnae reproduced in fig4 ,a are more characteristic of the species than are those of the slightly enlarged example represented in fig4 #bhj1 ,b4 ,illustration3 ,,fig4 #bhj4 ,onychiopsis ,mantelli4 7,from ,wealden specimens in the ,british ,museum2 ,no4 #acdie and ,no4 ,v4 #bfae4 ,a1 natural size2 ,b1 very slightly enlarged47 ,among ,british ,tertiary species referred to ,polypodiaceae1 it is interesting to find what may well be an authentic record of a fern closely allied to the recent tropical species ,acrostichum 7,chrysodium7 aureum4 ,this ,eocene species from ,bournemouth is described as ,chrysodium lanzaeanum#ida4 ,the frond is simply pinnate and apparently coriaceous in texture1 with lanceolate or oblong lanceolate pinnules 7fig4 #bfa1 ,a1 ,a1 p4 #cej71 differing from those of ,acrostichum aureum in being sessile4 ,a prominent midrib gives off numerous anastomosing veins4 ,no fertile pinnules have been found4 ,specimens described by ,forbes from the ,eocene beds of the ,island of ,mull as ,onoclea hebraidica#idb bear a strong likeness to the ,north ,american and ,japanese recent species ,onoclea sensibilis4 ,fertile specimens referred to the latter species are recorded by ,knowlton#idc from ,tertiary beds of ,montana4 ,a species described by ,saporta#idd from the ,eocene of ,szanne as ,adiantum apalophyllum is recorded by ,gardner and ,ettingshausen from ,bournemouth2 an identification which is based on somewhat meagre evidence4 ,the following remarks by ,gardner and ,ettingshausen are worthy of repetition as calling attention to circumstances often overlooked in analyses of fossil floras4 ,they speak of ferns as relatively rare in ,british ,eocene rocks and add1--8the floras consist principally of deciduous dicotyledonous leaves1 which 444 fell into the water and were tranquilly silted over4 ,ferns1 on the other hand1 would require some violence to remove them from the place of their growth1 and their preservation would consequently be exceptional1 and they would be mutilated and fragmentary4 ,this may account for their rarity4 ,few as the ,british ferns are in the number of species1 they nevertheless form the largest and most important series of ,eocene ferns1 even of ,tertiary ferns1 yet described from one group of beds#ide40 ,dipteridinae4 ,dictyophyllum4 ,this genus was founded by ,lindley and ,hutton for a pinnatifid leaf from the ,jurassic rocks of ,yorkshire which they regarded as probably dicotyledonous and named ,d4 rugosum#idf4 ,several ferns of this genus have since been found with well-preserved sori which demonstrate a close similarity to the recent fern ,dipteris4 ,dictyophyllum may be defined as follows3-- ,fronds large and palmate1 characterised by the equal dichotomy of the main rachis into two arms which curve outwards and then bend inwards 7fig4 #bha72 from the surface of each arm are given off numerous spreading pinnae with a lamina more or less deeply dissected into lobes varying in breadth and in the form of the apex4 ,each lobe has a median vein1 from which branches are given off approximately at right angles and then subdivide into a reticulum1 in the meshes of which the veinlets end blindly 7fig4 #bhb1 ,a and ,e74 ,sori composed of annulate sporangia are crowded on the lower surface of the lamina4 ,in habit and in sporangial characters the genus closely resembles ,dipteris1 and in the branching of the frond suggests comparison with ,matonia4 ,the rhizome 7,rhizomopteris7 is creeping and dichotomously branched1 bearing leaf-scars with a horse-shoe form of vascular strand4 ,illustration3 ,,fig4 #bha4 ,dictyophyllum exile4 7,after ,nathorst2 much reduced47 ,dictyophyllum is represented by several types to which various specific names have been assigned1 the distinguishing features being the form of the pinna lobes1 the degree of concrescence between the basal portions of the pinnae1 and similar features which in some cases can only be safely used as criteria when large specimens are available for comparison4 ,dictyophyllum exile 7,brauns74 ,figs4 #bha1 #bhb1 ,d1 ,e4 #ahfb4 ,camptopteris exilis1 ,brauns1 ,palaeontograph4 ,,ix4 p4 #ed4 #ahfg4 ,dictyophyllum acutilobum1 ,schenk1 ,foss4 ,flor4 ,grenz4 p4 #gg1 ,pls4 ,,xix4 ,,xx4 #ahgh4 ,d4 exile1 ,nathorst1 ,flora vid ,bjuf1 ,i4 p4 #ci1 ,pl4 ,v4 fig4 #g4 ---- ,d4 acutilobum1 ibid4 ,pl4 ,,xi4 fig4 #a4 ,the restoration1 after ,nathorst#idg1 shown in fig4 #bha illustrates the habit of this striking fern1 examples of which or of closely allied species are recorded from ,rhaetic rocks of ,germany1 ,scania1 ,persia1 ,bornholm1 ,tonkin1 ,china1 and elsewhere#idh4 ,the petiole1 reaching a length of #fj cm41 forks at the apex into two equal arms leaving between them an oval space and occasionally crossing one another4 ,the axes of these branches are twisted so that the pinnae1 which may be as many as #bd on each arm1 and arise from the inner side1 by torsion of the axes assume an external position4 ,an interesting analogy as regards the twisted rachis of ,dictyophyllum exile and ,camptopteris is afforded by the leaves of the ,cycads1 ,macrozamia ,fawcettiae and ,m4 corallipes1 which are also characterised by the torsion of the rachis4 ,the habit1 justly compared by ,nathorst with that of ,matonia pectinata1 affords another illustration of the common occurrence in older ferns of a dichotomous system of branching4 ,the pinnae1 characterised by circinate vernation1 reach a length of #fj cm4 and are divided into linear lobes inclined obliquely or at right angles to the pinna axis4 ,the whole of the under surface of the lamina may be covered with sporangia1 #d-g sporangia in each sorus2 the annulus is incomplete and approximately vertical 7fig4 #bhb1 ,d74 ,the rhizome is probably represented by the dichotomously branched axis described by ,nathorst from ,scania as ,rhizomopteris major2 the leaf-scars show a horse-shoe leaf-trace4 ,illustration3 ,,fig4 #bhb4 ,a4 ,dictyophyllum ,nilssoni4 ,b4 ,rhizomopteris ,schenki4 ,c4 ,camptopteris spiralis4 ,d1 ,e4 ,dictyophyllum exile4 7,after ,nathorst2 ,a1 ,b1 ,c1 ,e1 nat4 size47 ,dictyophyllum ,nathorsti ,zeiller#idi4 ,this type1 represented by a splendid series of specimens from the ,rhaetic beds of ,tonkin1 agrees very closely with ,d4 exile4 ,it differs1 however1 in the basal parts of the pinnae which are concrescent for a length of #e to #h cm4 instead of free as in ,d4 exile2 and1 to a slight degree1 in the form of the ultimate segments4 ,in habit and in soral characters the two species are practically identical4 ,each sorus contains #e to #h sporangia1 which are rather larger than those of ,dipteris4 ,dictyophyllum rugosum1 ,lind4 and ,hutt4 ,fig4 #bhc4 #ahbh4 ,phlebopteris ,phillipsii1 ,brongniart1 ,hist4 vg4 foss4 p4 #cgg1 ,pl4 ,,cxxxii4 fig4 #c2 ,pl4 ,,cxxxiii4 fig4 #a4 #ahbi4 ,phyllites nervulosis1 ,phillips1 ,geol4 ,yorks4 p4 #adh1 ,pl4 ,,viii4 fig4 #i4 #ahcd4 ,dictyophyllum rugosum1 ,lindley and ,hutton1 ,foss4 ,flor4 ,,ii4 ,pl4 ,,civ4 #ahcf4 ,polypodites heracleifolius1 ,goeppert1 ,foss4 ,farn4 p4 #cdd4 #ahdi4 ,camptopteris ,phillipsii1 ,brongniart1 ,tableau1 p4 #aje4 #ahhj4 ,clathropteris whitbyensis1 ,nathorst1 ,berttelse1 p4 #hc4 ,this species1 which is characteristic of ,jurassic rocks1 is less completely known than the two types described above1 but in the form and venation of the pinnae there is little difference between the ,rhaetic and ,jurassic plants4 ,the leaves of the ,jurassic species appear to have been smaller and more like those of ,dipteris conjugata 7fig4 #bca72 there are no indications of the existence of the two curved arms at the summit of the petiole which form so striking a feature in ,d4 exile and ,d4 ,nathorsti4 ,no sporangia have been found on ,english specimens1 but it is safe to assume their agreement with those of other species4 ,a more complete list of records of ,d4 rugosum is given in the first volume of the ,british ,museum ,catalogue of ,jurassic plants#iej4 ,illustration3 ,,fig4 #bhc4 ,dictyophyllum rugosum 7,lind4 and ,hutt474 7,brit4 ,mus4 ,nat4 size47 ,nathorst#iea has recently drawn attention to certain differences between ,dictyophyllum and ,dipteris4 ,the pinnate division of the pinnae is not represented in the fronds of the recent species1 but this method of lobing1 which is a marked characteristic of ,dictyophyllum1 is less prominent in ,clathropteris2 and in ,camptopteris lunzensis ,stur#ieb1 an ,austrian ,upper ,triassic species1 the pinnae are entire4 ,in ,dictyophyllum the sori cover the whole lower surface of the leaf2 in ,dipteris they are more widely separated and the sporangia have a diameter of #jjb mm41 but in ,dictyophyllum the diameter is #jd-jf mm4 ,moreover in ,dictyophyllum the sori contain #e to #h sporangia1 whereas in ,dipteris they are much more numerous4 ,despite these differences it is clear1 as ,nathorst says1 that ,dictyophyllum1 ,clathropteris1 and ,camptopteris are existing types very closely allied to ,dipteris4 ,it is a matter of secondary importance whether we include all in the ,dipteridinae or follow ,nathorst's suggestion and refer the fossil genera to the separate family ,camptopteridinae4 ,thaumatopteris4 ,this genus1 founded by ,goeppert#iec for a ,rhaetic plant from ,bayreuth1 is by some authors#ied regarded as identical with ,dictyophyllum1 but it has recently been resuscitated by ,nathorst#iee for specimens which he names ,t4 ,schenki1 formerly included by ,schenk in his species ,t4 ,brauniana#ief4 ,it bears a close resemblance1 in the long linear pinnules with an entire or crenulate margin1 to ,dictyophyllum ,fuchsi described by ,zeiller#ieg from ,tonkin1 and it would seem hardly necessary to adopt a distinctive generic designation4 ,the sporangia have a vertical or slightly oblique annulus and the rhizome is similar to that of ,dictyophyllum exile4 ,the habit of the genus is shown in fig4 #bhd1 which represents one of the ,german ,rhaetic species4 ,illustration3 ,,fig4 #bhd4 ,thaumatopteris ,mnsteri4 7,from a specimen in the ,bergakademie1 ,berlin2 nat4 size47 ,clathropteris4 ,clathropteris meniscoides1 ,brongn4 ,fig4 #bhe4 ,clathropteris1 founded by ,brongniart#ieh for ,rhaetic specimens from ,scania1 agrees very closely with some species of ,dictyophyllum1 but in view of the more rectangular form of the venation-meshes it is convenient to retain both names4 ,the type-species was originally named ,filicites meniscoides#iei and afterwards transferred to ,clathropteris4 ,an examination of ,brongniart's specimens has convinced ,nathorst of the specific identity of ,c4 meniscoides and ,c4 platyphylla4 ,the ,tonkin leaves described by ,zeiller#ifj under the latter name should1 therefore1 be included in ,c4 meniscoides1 which may be thus defined3 ,the petiolate frond is characterised by an equal dichotomy of the rachis1 as in ,dictyophyllum2 each branch bore #e-ae pinnae1 disposed en ventail1 reaching a length of #bj-cj cm4 and fused basally as in ,d4 ,nathorsti ,zeill4 ,pinnae linear lanceolate1 slightly contracted at the lower end and gradually tapered distally4 ,the lamina1 #c-ad cm4 broad1 is characterised by obtusely pointed marginal lobes4 ,from the midrib of each pinna lateral veins are given off at a wide angle1 and adjacent veins are connected by a series of branches which divide the lamina into a regular reticulum of rectangular and polygonal meshes 7fig4 #bhe74 ,the sori are abundant and contain #e-ab sporangia like those of ,dictyophyllum4 ,illustration3 ,,fig4 #bhe4 ,clathropteris meniscoides4 ,from ,rhaetic rocks near ,erlangen4 ,m4,s4 ,illustration3 ,,fig4 #bhf4 ,clathropteris egyptiaca4 7,nat4 size47 a1 b1 pieces of main ribs in grooves4 ,what is probably the rhizome of this species has been described by ,nathorst 7,rhizomopteris cruciata72 it is similar to that of ,dictyophyllum1 but the leaf-scars are more widely separated4 ,this species occurs in ,upper ,triassic1 ,rhaetic or ,lower ,jurassic rocks of ,scania1 ,france1 ,germany1 ,switzerland1 ,bornholm1 ,north ,america1 ,china1 ,tonkin1 and ,persia and is represented by fragments in the ,rhaetic beds of ,bristol#ifa4 ,clathropteris egyptiaca ,sew4#ifb ,fig4 #bhf4 ,the specimen on which this species was founded was discovered in the ,nubian ,sandstone east of ,edfu2 the age of the beds is uncertain1 but the presence of ,clathropteris suggests a ,lower ,jurassic or ,rhaetic horizon#ifc4 ,seven strong ribs radiate through the lamina from the summit of the petiole2 at a and b small pieces of the projecting ribs are shown in the grooves4 ,from the main veins slender branches are given off at right angles and1 as seen in the enlarged drawing1 these again subdivide into a delicate reticulum with free-ending veinlets4 ,illustration3 ,,fig4 #bhg4 ,camptopteris spiralis4 7,after ,nathorst4 ,much reduced47 ,camptopteris4 ,camptopteris spiralis1 ,nath4 ,figs4 #bhb1 ,c2 #bhg4 ,nathorst proposed this generic name for ,rhaetic fronds#ifd resembling those of ,clathropteris and ,dictyophyllum1 but differing in the form of the pinnae and in habit4 ,the habit of the type-species1 ,c4 spiralis1 is shown in fig4 #bhg4 ,an examination of the specimens in the ,stockholm ,museum convinced me of the correctness of ,nathorst's restoration#ife4 ,each of the forked arms of the rachis bore as many as #aej-afj long and narrow pinnae characterised by an anastomosing venation 7fig4 #bhb1 ,c7 and by a spiral disposition due to the torsion of the axes4 ,the sporangia agree in essentials with those of ,dictyophyllum4 ,hausmannia4 ,a critical and exhaustive account of this genus has been given by ,prof4 ,von ,richter#iff based on an examination of specimens found in the ,lower ,cretaceous rocks of ,quedlinburg in ,germany4 ,the name was proposed by ,dunker#ifg for leaves from the ,wealden of ,germany characterised by a deeply dissected dichotomously branched lamina4 ,andrae subsequently instituted the genus ,protorhipis#ifh for suborbicular leaves with dichotomously branched ribs from the ,lias of ,steierdorf4 ,a similar but smaller type of leaf was afterwards described by ,zigno#ifi from ,jurassic beds of ,italy as ,p4 asarifolius1 and ,nathorst#igj figured a closely allied form from ,rhaetic rocks of ,sweden4 ,while some authors regarded ,hausmannia and ,protorhipis as ferns1 others compared them with the leaves of ,baiera 7,ginkgoales72 ,saporta suggested a dicotyledonous affinity for leaves of the ,protorhipis type4 ,the true nature of the fossils was recognised by ,zeiller#iga1 who called attention to the very close resemblance in habit and in soral characters to the recent genus ,dipteris4 ,a comparison of the different species of ,dipteris1 including young leaves 7fig4 #bca1 p4 #big71 with those of the fossil species reveals a very striking agreement#igb4 ,there can be no doubt1 as ,richter points out1 that the names ,hausmannia and ,protorhipis stand for one generic type4 ,hausmannia may be defined as follows3 ,rhizome creeping1 slender1 dichotomously branched2 leaf-stalks slender 7#b-be cm4 long71 bearing a leathery lamina 7#a-ab cm4 long and broad71 wedge-shaped below1 occasionally cordate or reniform1 entire or more or less deeply lobed into broad linear segments4 ,the leaf is characterised by dichotomously branched main ribs which arise from the summit of the rachis as two divergent arms and radiate in a palmate manner1 with repeated forking1 through the lamina4 ,lateral veins are given off at a wide angle1 and1 by subdivision1 form a fairly regular network similar to that in ,dictyophyllum1 ,clathropteris1 and ,dipteris4 ,illustration3 ,,fig4 #bhh4 ,hausmannia dichotoma4 7,specimens from the late ,dr ,marcus ,gunn's ,collection of ,upper ,jurassic plants1 ,sutherlandshire2 very slightly reduced47 ,hausmannia dichotoma1 ,dunker#igc4 ,fig4 #bhh1 ,a1 ,b4 ,this ,wealden species1 represented in the ,north ,german flora and in beds of approximately the same age at ,quedlinburg1 has been discovered by ,dr ,marcus ,gunn in ,upper ,jurassic rocks on the north-east coast of ,scotland4 ,the lamina 7#ab cm4 or more in length7 is divided into five to seven linear segments and bears a close superficial resemblance to leaves of ,baiera and to recent species of ,schizaea 7fig4 #bbb1 p4 #bhg74 ,each segment contains one or two main ribs 7fig4 #bhh1 ,a74 ,a similar form is described by ,bartholin#igd and by ,moeller#ige as ,h4 ,forchammeri from ,jurassic rocks of ,bornholm4 ,hausmannia ,kohlmanni1 ,richt4 ,fig4 #bgh1 ,f4 ,in this species1 instituted by ,richter from material obtained from the ,lower ,cretaceous beds of ,strohberg#igf1 the comparatively slender rhizome bears fronds with petioles reaching a length in extreme cases of #be cm4 but usually of about #aj cm4 ,the lamina 7#a-g cm4 long and #a-aj cm4 broad7 is described as leathery1 obcordate1 and divided into two symmetrical halves by a median sinus which1 though occasionally extending more than half-way through the lamina1 is usually shallow4 ,the venation consists of two main branches which diverge from the summit of the petiole 7fig4 #bgh1 ,f7 and subdivide into dichotomously branched ribs2 finer veins 7not shown in the drawing7 are given off from these at right angles and form more or less rectangular meshes as in other members of the ,dipteridinae and in such recent ferns as ,polypodium quercifolium 7fig4 #bca1 ,d1 p4 #big74 ,the imperfect lamina represented in fig4 #bhi may belong to ,hausmannia ,richteri or may be a distinct species2 it shows some of the finer veins connecting the shorter forked ribs1 which formed part of the reticulate ramifying system in the mesophyll4 ,this specimen was obtained from the plant-beds of ,culgower on the ,sutherlandshire coast1 which have been placed by some geologists in the ,kimmeridgian series4 ,the smaller type represented in fig4 #bgh1 ,e1 is referred by ,richter to a distinct species1 ,hausmannia ,sewardi#igg1 founded on a few specimens from the ,lower ,cretaceous strata of ,strohberg4 ,this species is characterised by a stouter rhizome bearing smaller leaves consisting of a short petiole 7#c-d cm4 long7 and an obovate lamina 7#a-b cm4 long and broad74 ,there are usually two opposite leaflets on each leaf-stalk1 and these may be equivalent to the two halves of a single deeply dissected lamina4 ,illustration3 ,,fig4 #bhi4 ,hausmannia sp4 ,upper ,jurassic1 near ,helmsdale1 ,scotland4 ,from a specimen in the ,british ,museum4 7,nat4 size47 ,it is interesting to compare these different forms of ,hausmannia with the fronds of recent species of ,dipteris represented in fig4 #bca4 ,the more deeply dissected type1 such as ,h4 dichotoma1 closely resembles ,d4 ,lobbiana or ,d4 quinquefurcata1 while the more or less entire fossil leaves 7fig4 #bgh1 ,e1 ,f and fig4 #bhi7 are very like the somewhat unusual form of ,dipteris conjugata shown in fig4 #bca1 ,b1 p4 #big4 ,other species of the genus are recorded from ,liassic rocks of ,steierdorf#igh 7,hungary7 and of ,bornholm#igi4 ,nathorst#ihj has described a small ,rhaetic species from ,scania3 a ,french ,permian plant described by ,zeiller#iha and compared by him with ,h4 dichotoma1 may be a ,palaeozoic example of this ,dipteris-like genus4 ,some segments of leaves from the ,eocene beds 7,middle ,bagshot7 of ,bournemouth1 and now in the ,british ,museum1 described by ,gardner and ,ettingshausen#ihb as ,podoloma polypodioides1 bear a close resemblance in the venation to the lamina of ,dipteris conjugata4 ,,chapter ,,xxii4 ,marattiales 7,fossil74 ,the discovery of ,pteridosperms has necessarily led to a considerable modification of the views formerly held that existing genera of ,marattiaceae represent survivors of a group which occupied a dominant position in the forests of the ,coal age4 ,mr ,arber writes3--8,the evidence1 formerly regarded as beyond suspicion1 that the eusporangiate ferns formed a dominant feature of the vegetation of the ,palaeozoic period1 has been undermined1 more especially by the remarkable discovery of the male organs of ,lyginodendron by ,mr ,kidston4 ,at best we can only now regard them as a subsidiary group in that epoch in the past history of the vegetable kingdom#ihc40 ,dr ,scott expresses himself in terms slightly more favourable to the view that the ,marattiaceae represent the aristocracy among the ,filicales4 ,he says3--8,we now have to seek laboriously for evidence1 which formerly seemed to lie open to us on all hands4 ,i believe1 however1 that such careful investigation will result in the resuscitation of the ,palaeozoic ferns as a considerable1 though not as a dominant group#ihd40 ,zeiller's faith#ihe in the prospect of ,marattiaceous ferns retaining their position as prominent members of ,palaeozoic floras1 though shaken1 is not extinguished3 he recognises that they played a subordinate part4 ,reference has already been made to the impossibility of determining whether ,palaeozoic fern-like fronds may be legitimately retained in the ,filicales1 or whether they must be removed into the ever widening territory of the ,pteridosperms4 ,the difficulty is that the evidence of reproductive organs is very far from decisive4 ,in the absence of the female reproductive organs1 the seeds1 we cannot in most cases be certain whether the small sporangium-like bodies on fertile pinnules are true fern sporangia or the microsporangia of a heterosporous pteridosperm4 ,what is usually called an exannulate fern sporangium1 such as we have in ,angiopteris and in many ,palaeozoic plants1 has no distinguishing features which can be used as a decisive test4 ,the microsporophylls of the ,mesozoic ,bennettitales produced their spores in sporangial compartments grouped in synangia like those of recent ,marattiaceae2 and in the case of ,crossotheca1 a type of frond always regarded as ,marattiaceous until ,kidston#ihf proved it to be the microsporophyll of ,lyginodendron1 we have a striking instance of the futility of making dogmatic assertions as to the filicinean nature of what look like true fern sporangia4 ,in all probability ,dr ,kidston's surmise that the supposed fern sporangia known as ,dactylotheca1 ,renaultia1 ,urnatopteris are the microsporangia of ,pteridosperms will be proved correct#ihg4 ,the question is how many of the supposed ,marattiaceous sporangia must be assigned to ,pteridosperms8 ,there is1 however1 no reasonable doubt that true ,marattiaceae formed a part of the ,upper ,carboniferous flora4 ,all that can be attempted in the following pages is to describe briefly some of the numerous types of sporangia recognised on ,palaeozoic fern-like foliage1 leaving to the future the task of deciding how many of them can be accepted as those of ferns4 ,it is impossible to avoid overlapping and some repetition in the sections dealing with true ,ferns and with ,pteridosperms4 ,the filicinean nature of the stem known as ,psaronius 7see page #dae7 has not as yet been questioned4 ,the nomenclature of supposed ,marattiaceous species from ,carboniferous and ,permian rocks is in a state of some confusion owing to a lack of satisfactory distinguishing features between certain types to which different generic names have been assigned4 ,as we have already seen in the case of supposed leptosporangiate sporangia1 the interpretation of structural features in petrified or carbonised sporangia does not afford an example of unanimity among palaeobotanical experts4 ,ptychocarpus4 ,this generic name1 proposed by the late ,professor ,weiss#ihh1 is applied to a type of fructification illustrated by the plant which ,brongniart named ,pecopteris unita1 a species common in the ,upper ,coal-,measures of ,england#ihi4 ,it is adopted by ,kidston for fertile specimens from ,radstock which he describes as ,ptychocarpus oblongus#iij1 but the precise nature of the fertile pinnules of this species cannot be determined4 ,ptychocarpus unita 7,brongn4#iia74 ,fig4 #bia1 ,a1 ,b4 7 ,goniopteris unita1 ,grand',eury47 ,this species has tripinnate fronds with linear pinnae bearing contiguous pinnules of the ,pecopteris type 7fig4 #bia1 ,b71 #d-e mm4 long1 confluent at the base or for the greater part of their length4 ,on the under surface of the fertile segments1 which are identical with the sterile1 occur circular synangia 7fig4 #bia1 ,a7 consisting of seven sporangia embedded in a common parenchymatous tissue and radially disposed round a receptacle supplied with vascular tissue4 ,the synangium is described as shortly stalked like those of ,marattia ,kaulfussii 7fig4 #bde1 ,b1 p4 #cbj74 ,in shape1 in the complete union of the sporangia1 and presumably in the apical dehiscence1 ,ptychocarpus agrees very closely with ,kaulfussia 7fig4 #bde72 but we cannot be certain that we have not a collection of microsporangia simulating a fern synangium4 ,a synangium closely resembling ,ptychocarpus has been described by ,mr ,watson#iib from the ,lower ,coal-,measures of ,lancashire as ,cyathotrachus altus1 but there is no convincing evidence as to the nature of the plant on which it was borne4 ,danaeites4 ,this generic name1 instituted by ,goeppert#iic1 has been used by authors without due regard to the nature of the evidence of affinity to ,danaea4 ,the type named by ,stur ,danaeites sarepontanus#iid 7fig4 #bia1 ,e7 bears small pecopteroid pinnules with ovoid sporangia in groups of #h-af in two contiguous series on the lower face of the lamina4 ,the sporangia dehisce by an apical pore and are more or less embedded in the mesophyll of the segments4 ,no figures have been published showing any detailed sporangial structure1 and such evidence as we have is insufficient to warrant the conclusion that the resemblance to ,danaea is more than an analogy4 ,parapecopteris4 ,parapecopteris neuropteroides1 ,grand',eury4 ,fig4 #bij1 ,d4 ,the plant described by ,grand',eury#iie from the ,coal-fields of ,gard and ,st tienne1 and made the type of a new genus1 is characterised by pinnules intermediate between those of ,pecopteris and ,neuropteris#iif and by the presence of two rows of united sporangia along the lateral veins1 as in ,danaea and ,danaeites4 ,asterotheca4 ,certain species of ,pecopteris fronds from ,carboniferous strata are characterised by circular sori or synangia consisting of a small number 7#c-h7 of exannulate sporangia attached to a central receptacle and free only at their apices4 ,strasburger#iig suggested a ,marattiaceous affinity for ,asterotheca and ,stur#iih describes the species ,asterotheca ,sternbergii ,goepp4 7fig4 #bia1 ,c1 ,d7 as an example of a ,marattiaceous fern4 ,the latter author retains ,corda's genus ,hawlea#iii for the fertile fronds of the common ,coal-,measures species ,pecopteris ,miltoni1 while on the other hand ,kidston#ajjj includes this type in ,asterotheca4 ,pecopteris 7,asterotheca7 ,miltoni 7,artis74 #ahbe4 ,filicites ,miltoni1 ,artis1 ,antedil4 ,phyt4 ,pl4 ,,xiv4 #ahbh4 ,pecopteris ,miltoni1 ,brongniart1 ,prodrome1 p4 #eh4 #ahbh4 ,pecopteris abbreviata1 ,brongniart1 ,hist4 vg4 foss4 p4 #ccg1 ,pl4 ,,cxv4 figs4 #a-d2 ,lindley and ,hutton1 ,foss4 ,flor4 ,vol4 ,,iii4 ,pl4 #ahd4 #ahde4 ,hawlea pulcherrima1 ,corda1 ,flor4 ,vorwelt1 p4 #ij1 ,pl4 ,,lvii4 figs4 #g1 #h4 #ahgg-ahhh4 ,hawlea ,miltoni1 ,stur1 ,culm ,flora1 p4 #bic2 ,farne ,carbon4 ,flora1 p4 #ajh1 ,pls4 ,,lix4 ,,lx4 #ahhh4 ,pecopteris 7,asterotheca7 abbreviata1 ,zeiller1 ,flor4 ,valenc4 p4 #ahf1 ,pl4 ,,xxiv4 figs4 #a-d4 ,illustration3 ,,fig4 #bij4 ,a4 ,alethopteris lonchitica4 #b4 ,for description ,b4 ,lonchopteris rugosa4 #b4 see ,chap4 ,,xxvii4 ,c4 ,sphenopteris ,hoeninghausi4 #d4 ,d4 ,parapecopteris neuropteroides4 ,e4 ,pecopteris 7,dactylotheca7 plumosa ,p4 7,dactylotheca7 dentata ,zeiller 7#hh74 #d4 7,a-,c1 ,e1 after ,zeiller2 ,d1 after ,grand',eury47 ,the fronds of this species reached a length of more than #c metres and a breadth of #b metres4 ,they are characterised by the presence of aphlebiae#ajja appressed to the rachis and by circular sori composed of a small number 7#c-f7 of sporangia4 ,in habit and in the form of the pinnules this type is similar to ,dactylotheca plumosa4 ,illustration3 ,,fig4 #bia4 ,a1 ,b4 ,ptychocarpus unita4 ,c1 ,d4 ,asterotheca ,sternbergii4 ,e4 ,danaeites sarepontanus4 ,f4 ,hawlea ,miltoni4 ,g4 ,hawlea pulcherrima4 ,h-,k4 ,scolecopteris elegans4 7,a1 ,b1 after ,renault2 ,c-,g1 after ,stur2 ,h1 ,i1 after ,strasburger2 ,k1 after ,sterzel47 ,hawlea4 ,stur#ajjb retains this generic name for sori in which the sporangia are free and united only by the proximal end to a central receptacle 7fig4 #bia1 ,f1 ,g74 ,he describes the individual sporangia as possessing a rudimentary annulus1 a comparatively strong wall1 and terminating in a pointed distal end4 ,he emphasises the greater degree of cohesion between the sporangia of ,asterotheca as the distinguishing feature of that genus2 but this is a character difficult to recognise in some cases1 and from the analogy of recent ferns one is disposed to attach little importance to the greater or less extent to which sporangia are united1 at least in such cases as ,asterotheca and ,hawlea when the cohesion is never complete4 ,scolecopteris4 ,zenker#ajjc gave this name to detached fertile pinnules from the ,lower ,permian of ,saxony1 which he described as ,scolecopteris elegans4 ,he recognised the fern nature of the sori and suggested that the pinnules might belong to the fronds of one of the 8,staarsteinen0 7,psaronius71 a view which subsequent investigations render far from improbable4 ,the sori1 which occur in two rows on the lower surface of the small pecopteroid segments with strongly revolute margins 7fig4 #bia1 ,h-,k71 contain #d-e sporangia attached to a stalked receptacle comparable with that of ,marattia ,kaulfussii4 ,these pedicellate synangia were fully described by ,strasburger#ajjd1 who decided in favour of a ,marattiaceous alliance4 ,the lower portions of the distally tapered sporangia are concrescent1 the distal ends being free 7fig4 #bia1 ,h74 ,stur includes in ,scolecopteris the common species ,pecopteris arborescens 7fig4 #cgf71 but ,kidston#ajje states that the ,british example of ,scolecopteris is ,s4 polymorpha1 ,brongn4 from the ,upper ,coal-,measures4 ,scolecopteris elegans ,zenk4 furnishes an example of a plant1 or plant fragment1 which has been assigned to the animal kingdom4 ,geinitz#ajjf described silicified pinnules as ,palaeojulus dyadicus1 the generic name being chosen because of the resemblance to ,millipedes such as the genus ,julus4 ,the mistake is not surprising to anyone who has seen a block of siliceous rock from ,chemnitz crowded with the small pinnules with their concave surfaces formed by the infolding of the edges4 ,sterzel#ajjg1 who pointed out the confusion between ,myriapods and ,filices1 has published figures which illustrate the deceptive resemblance of the pinnules1 with their curved lamina divided by lateral veins into segments1 to the body of a ,millipede 7fig4 #bia1 ,k74 ,he points out that ,geinitz searched in vain for the head and legs of ,palaeojulus and expressed the hope that further examination would lead to fresh discoveries3 the examination of sections revealed the presence of sporangia and demonstrated the identity of ,palaeojulus and ,scolecopteris4 ,discopteris4 ,stur#ajjh instituted this genus for fertile fronds from the ,upper ,carboniferous ,schatzlarer beds1 including two species ,discopteris karwinensis and ,d4 ,schumanni4 ,he described the small ,sphenopteroid pinnules as characterised by disc-shaped sori made up of #gj-ajj sporangia attached to a hemispherical receptacle3 the absence of a true annulus led him to refer the genus to the ,marattiaceae4 ,in his memoir on the coal-basin of ,heraclea 7,asia ,minor71 ,zeiller#ajji instituted the species ,sphenopteris 7,discopteris7 ,rallii and figured sporangia resembling those described by ,stur in the possession of a rudimentary 8apical annulus40 ,he compared the sporangia with those of recent ,osmundaceae and ,marattiaceae4 ,in the later memoir on the ,upper ,carboniferous and ,permian plants of ,blanzy and ,creusot1 ,zeiller#ajaj gives a very full and careful description of fertile specimens of ,sphenopteris 7,discopteris7 cristata1 a fern originally described by ,brongniart as ,pecopteris cristata#ajaa4 ,many of the ,sphenopteroid pinnules of this quadripinnate fern frond show the form and structure of the sori with remarkable clearness in the admirable photographs reproduced in ,plates ,i4-,,iii4 of ,zeiller's ,blanzy memoir4 ,the lobed pinnules of this species are of oval-triangular form1 #e-ae mm4 long and #be-f mm4 broad#ajab4 ,an examination of the type-specimens of ,discopteris from ,vienna enabled ,zeiller to correct ,stur's original description of the sori3 he found that the ,austrian and ,french specimens1 though specifically distinct1 undoubtedly belong to one genus4 ,the sori in ,discopteris cristata are globular1 as in the recent genera ,cyathea and ,alsophila1 and frequently cover the whole face of the lamina4 ,the individual sporangia are #jd-je mm4 long and #jae-jb mm4 in diameter2 they are exannulate1 but for the annulus is substituted a group of thicker-walled and larger cells in the apical and dorsal region4 ,the description by ,stur of a hemispherical receptacle seemed to indicate an important difference between the ,austrian and ,french species2 but ,zeiller found that this feature does not actually exist and that it was so described as the result of misinterpretation4 ,zeiller succeeded in isolating spores1 #dj-ej in diameter1 from some of the sporangia of ,d4 cristata and found that they exhibited the three-rayed pattern characteristic of fern-spores and which is indicative of their formation in tetrads4 ,the conclusion arrived at is that the genus ,discopteris1 as represented by ,d4 karwinensis1 ,d4 cristata etc41 may be regarded as a true fern and included in the ,marattiaceae4 ,as ,zeiller points out1 the sori of ,discopteris differ from those of recent ,marattiaceae in their pluriseriate construction and agree in this respect with those of the ,cyatheaceae4 ,the comparison already made#ajac between the sporangia of ,d4 ,rallii and those of recent ,osmundaceae holds good3 the genus affords another example of a generalised type1 in this case probably a fern1 combining features which are now distributed among the ,marattiaceae1 ,osmundaceae and ,cyatheaceae4 ,in addition to genera founded on true synangia or groups of free or partially united sporangia1 the literature of ,palaeozoic ferns contains several generic names applied to sporangia which occur singly on ,sphenopteroid or ,pecopteroid pinnules4 ,the following may serve as examples2 but it should be stated that these will probably be transferred eventually to the ,pteridosperms4 ,it is1 however1 immaterial whether they are dealt with here or in the chapter devoted to the seed-bearing 8ferns40 ,dactylotheca4 ,zeiller#ajad created this genus for fertile fronds of ,pecopteris dentata ,brongn4 7 ,p4 plumosa ,artis#ajae71 a common ,british species in the ,upper and ,middle ,coal-,measures4 ,stur#ajaf included ,p4 dentata in his list of species of ,senftenbergia1 the genus to which reference was made under the ,schizaeaceae4 ,pecopteris 7,dactylotheca7 plumosa 7,artis74 ,figs4 #bij1 ,e1 #bib1 #bic4 #ahbe4 ,filicites plumosus1 ,artis1 ,antedil4 ,phyt4 p4 #ag1 ,pl4 ,,xvii4 #ahbh4 ,pecopteris plumosa1 ,brongniart1 ,hist4 vg4 foss4 p4 #cdh1 ,pls4 ,,cxxi4 ,,cxxii4 ---- ,p4 dentata1 ,brongniart1 ibid4 ,pls4 ,,cxxiii4 ,,cxxiv4 ---- ,p4 delicatulus1 ,brongniart1 ibid4 ,pl4 ,,cxvi4 fig4 #f4 #ahcb4 ,sphenopteris caudata1 ,lindley and ,hutton1 ,foss4 ,flor4 ,vol4 ,i4 ,pl4 ,,xlviii42 ,vol4 ,,ii4 ,pl4 ,,cxxxviii4 #ahcd4 ,pecopteris serra1 ,lindley and ,hutton1 ibid4 ,vol4 ,,ii4 ,pl4 ,,cvii4 #ahcd4 ,schizopteris adnascens1 ,lindley and ,hutton1 ibid4 ,vol4 ,i4 ,pls4 ,c4 ,,ci4 #ahcf4 ,aspidites caudatus1 ,goeppert1 ,syst4 fil4 foss4 p4 #cfc4 #ahch4 ,steffensia silesiaca1 ,presl1 in ,sternberg1 ,flor4 ,vorwelt1 ,vers4 ,,ii4 p4 #abb4 #ahfi4 ,pecopteris silesiacus1 ,schimper1 ,trait4 pal4 vg4 ,vol4 ,i4 p4 #eag4 ---- ,cyathocarpus dentatus1 ,weiss1 ,flora der jngst4 ,stk4 und ,roth4 p4 #hf4 #ahgg4 ,senftenbergia plumosa1 ,stur1 ,culm ,flora1 ,,ii4 p4 #ahg 7#bic74 ---- ,s4 dentata1 ibid4 #ahhf4 ,dactylotheca plumosa1 ,kidston1 ,cat4 ,palaeozoic ,plants1 p4 #abh4 #ahhh4 ,dactylotheca dentata1 ,zeiller1 ,flor4 ,valenc4 ,pls4 ,,xxvi4-,,xxviii4 ,for a fuller synonymy reference should be made to ,kidston's account of this species#ajag1 from which the above list is compiled4 ,the large fronds of this species are tri- or quadripinnate4 ,the pinnules vary much in shape and size and in degree of lobing1 according to their position on the frond 7fig4 #bic74 ,the primary pinnae are subtended by two ,aphlebiae 7fig4 #bic1 ,a7 appressed to the rachis1 like the delicate leaves of the recent fern ,teratophyllum aculeatum 7see page #cja74 ,the sporangia 7#je-jfe7 are oval and exannulate and are attached parallel to the lateral veins2 they may occupy the whole of the space between the midrib and the edge of the pinnules4 ,this species occurs in the ,upper1 ,middle1 and ,lower ,coal-,measures of ,britain1 reaching its maximum in the ,upper ,coal-,measures4 ,the aphlebiae undoubtedly served to protect the young fronds1 as shown by a specimen figured by ,kidston 7fig4 #bic1 ,b72 they may also have served other purposes1 as suggested by the above comparison with ,teratophyllum1 in the mature frond4 ,lindley and ,hutton regarded the aphlebiae as leaves of a fern climbing up the rachis2 which they named ,schizopteris adnascens1 a confusion similar to that already mentioned in the description of ,hemitelia capensis 7see p4 #cjd74 ,illustration3 ,,fig4 #bib4 ,dactylotheca plumosa4 7,after ,kidston4 ,slightly reduced47 ,illustration3 ,,fig4 #bic4 ,dactylotheca plumosa3 ,a4 ,rachis with ,aphlebiae4 ,b1 a1 young pinnae circinately folded4 7,after ,kidston4 ,a1 ,b1 nat4 size47 ,renaultia4 ,this name was proposed by ,zeiller#ajah for ,upper ,carboniferous fertile pinnae of the ,sphenopteroid type1 bearing ovoid sporangia either singly or in marginal groups of #b to #e at the ends of the veins4 ,the appearance of the apical cells occasionally suggests the presence of a rudimentary annulus4 ,kidston has recorded this type of fructification in ,britain#ajai4 ,stur describes fertile pinnules of the same type under the generic name ,hapalopteris#ajbj4 ,zeilleria4 ,this genus was founded by ,kidston#ajba for fertile pinnae of a very delicate fern1 ,zeilleria delicatula 7,sternb47 characterised by filiform ultimate segments bearing an indusium-like body1 spherical when immature and splitting at maturity into four small valves4 ,kidston1 in his earlier paper1 compared the species with recent ,hymenophyllaceae4 ,in the same genus he includes ,z4 avoldensis#ajbb 7,stur7 assigned by ,stur to ,calymmatotheca1 a genus described by some authors as characterised by groups of radially elongated sporangia at the tips of the pinnules2 these supposed sporangia are now known to be the valves of an indusium-like organ or cupule1 as ,stur asserted4 ,there can be little doubt that the fertile fronds placed in ,calymmatotheca and in ,zeilleria were borne by ,pteridosperms4 ,urnatopteris4 ,the ,upper ,carboniferous fronds of a delicate ,sphenopteris habit1 to which this name was assigned by ,kidston#ajbc1 were described by him as ,eusphenopteris tenella 7,brongn47#ajbd and compared with ,hymenophyllaceae2 subsequently ,kidston expressed the opinion that ,urnatopteris may be a ,marattiaceous fern1 as ,williamson#ajbe believed2 he has since suggested that the sporangia are the microsporangia of a ,pteridosperm#ajbf4 ,the sterile and fertile pinnae differ in the absence of a lamina in the latter4 ,the sporangia 7or microsporangia7 are characterised by a poricidal dehiscence4 ,the records from strata higher in the geological series than the ,permian1 disregarding many of doubtful value1 afford ample testimony to the existence of ,marattiaceae in ,upper ,triassic and ,rhaetic floras4 ,marattiopsis4 ,the generic name ,danaeopsis was applied by ,heer#ajbg to an ,upper ,triassic fern1 previously described by ,presl as ,taeniopteris marantacea4 ,a splendid specimen from the ,keuper of ,stuttgart is figured in ,schimper's ,atlas#ajbh showing the pinnate habit of the frond and the broadly linear segments1 #be cm4 #ce cm41 bearing rows of contiguous sporangia4 ,the large pinnules have a strong midrib giving off curved and forked lateral veins4 ,presl's species may most appropriately be included in the genus ,marattiopsis4 ,a specimen of ,m4 marantacea described by ,leuthardt#ajbi as ,danaeopsis marantacea from the ,upper ,trias of ,basel shows a peculiarity in the venation2 the lateral veins often fork near their origin1 as noticed by other authors1 but each vein forks a second time near the edge of the lamina and the two arms converge1 forming a series of intramarginal loops 7fig4 #bfe1 ,b74 ,marattiopsis ,muensteri 7,goepp474 ,fig4 #bde1 ,d1 ,e4 ,this widely spread ,rhaetic plant affords the best example of a post-,permian species which may be accepted as an authentic record of fossil ,marattiaceae4 ,various generic names have been used for this species2 ,goeppert originally described the plant as ,taeniopteris ,muensteri#ajcj2 ,schimper#ajca proposed the name ,marattiopsis1 and ,schenk#ajcb substituted ,angiopteris on the ground that the fertile pinnules resemble that genus rather than ,marattia4 ,marattiopsis1 if interpreted as indicating a family resemblance rather than special affinity to the genus ,marattia1 would seem to be the more appropriate designation4 ,this species has been figured by several authors and in many instances with fertile pinnules2 the best illustrations are those published by ,zeiller#ajcc in his monograph of ,tonkin plants4 ,the pinnate fronds are characterised by a broad rachis bearing sessile broadly linear pinnules rounded at the base1 obtusely pointed at the apex1 reaching a length of #ae-bj cm4 and a breadth of #ab-ce mm4 ,from a well-marked midrib are given off secondary veins dichotomously branched close to their origin4 ,the linear synangia near the ends of the veins contain two rows of sporangial compartments and open as two valves as in ,marattia4 7,cf4 fig4 #bde1 ,a1 p4 #cbj47 ,sidenote3 ,,danaeopsis ,this species occurs in the ,rhaetic beds of ,scania1 ,franconia1 and ,tonkin4 ,a similar type is figured by ,fontaine from ,jurassic beds in ,california as ,angiopteridium californicum#ajcd1 and ,bartholin#ajce and ,moeller#ajcf record ,m4 ,muensteri from the ,lias of ,bornholm4 ,schenk's species from ,china#ajcg1 ,angiopteris ,richthofeni1 is a closely allied species1 and a similar form is recorded from ,jurassic and ,caucasian strata#ajch4 ,the microscopical examination by ,nathorst#ajci of a group of spores from a synangium of ,m4 ,muensteri shows that they resemble those of recent ,marattiaceae4 ,from the ,upper ,triassic plant beds of ,lunz1 ,stur has included several species of ferns in the ,marattiaceae1 and of these ,krasser#ajdj has recently published full diagnoses but unfortunately without illustrations4 ,in addition to ,marattiopsis marantacea 7,presl7 the list includes species referred to ,coniopteris1 to ,speirocarpus1 a genus founded by ,stur1 to ,oligocarpia1 ,asterotheca1 and ,bernouillia 7,heer74 ,as already pointed out1 some at least of these ,austrian ferns are more probably ,osmundaceous than ,marattiaceous4 ,danaeopsis ,hughesi1 ,feistmantel4 ,the pinnate fronds described by ,feistmantel#ajda from the ,middle ,gondwana rocks of ,india and recorded from ,rhaetic strata in ,south ,africa#ajdb1 ,china#ajdc1 and ,tonkin#ajdd1 may belong to a member of the ,marattiaceae1 but no fertile specimens have been described4 ,the close agreement between the sterile leaves from ,india and ,south ,africa and the fertile fronds of ,marattiopsis marantacea suggests generic identity4 ,the ,upper ,triassic ferns described by ,heer1 ,krasser#ajde1 and ,leuthardt#ajdf as ,bernouillia have been referred to the ,marattiaceae1 but without trustworthy evidence in favour of this affinity4 ,the large leaves1 #gj cm4 long and #g cm4 broad1 described by ,zigno#ajdg from the ,jurassic of ,italy as ,danaeites ,heeri1 are probably ,cycadean4 ,the ,polish ,jurassic species ,danaea microphylla#ajdh is a more satisfactory record4 ,illustration3 ,,fig4 #bid4 ,a1 ,b4 ,nathorstia angustifolia1 ,heer4 7,after ,heer4 ,a1 nat4 size47 ,c1 ,d4 ,sorus of ,n4 latifolia1 ,nath4 7,after ,nathorst4 ,c1 #ab2 ,d1 #de47 ,nathorstia4 ,this name was instituted by ,heer#ajdi for pieces of pinnate fronds from ,lower ,cretaceous rocks of ,greenland4 ,the resemblance of the long pinnules to the fertile segments of ,laccopteris is so close that generic identity might well be assumed1 but it has recently been shown by ,nathorst#ajej that the soral characters justify ,heer's use of a distinctive name for the ,arctic fern4 ,the circular sori arranged in two rows 7fig4 #bid1 ,a1 ,b7 are superficially identical with those of ,laccopteris1 but consist of concrescent sporangia forming a circular synangium 7fig4 #bid1 ,c1 ,d7 like those of ,kaulfussia and ,ptychocarpus4 ,the lighter areas in fig4 #bid1 ,d1 represent the sporangia3 fig4 ,c shows the radial disposition of the numerous sporangial compartments round a central receptacle4 ,from a stout midrib lateral veins arise at right angles1 but their distal terminations are not preserved4 ,it is probable1 as ,nathorst suggests1 that ,bayer's#ajea species ,drynaria fascia from the ,lower ,cretaceous rocks of ,bohemia should be referred to ,heer's genus4 ,in the absence of well-preserved sori it would be exceedingly difficult1 or even impossible1 to distinguish between pinnules of ,laccopteris and ,nathorstia4 ,a ,tertiary species1 ,marattia ,hookeri 7fig4 #bfa1 ,c1 p4 #cej71 described by ,gardner and ,ettingshausen#ajeb from the ,eocene beds of the ,isle of ,wight is referred by them to the ,marattiaceae because of a resemblance of the sterile pinnae to those of ,m4 ,kaulfussii2 but this is insufficient evidence of relationship4 ,,chapter ,,xxiii4 ,psaronieae4 ,this family name1 first suggested by ,unger1 may be conveniently adopted for the numerous species of petrified tree-fern stems characteristic of the ,lower ,permian and ,upper ,carboniferous strata4 ,in his monograph ber die ,staarsteine published in #ahed1 ,stenzel#ajec referred to the ,psaronieae as a special subdivision of the ,filices most nearly allied to the ,polypodiaceae4 ,there is now a consensus of opinion in favour of including ,psaronius in the ,marattiales1 or at least of regarding the genus as more closely allied to the ,marattiaceae than to any other family4 ,while admitting that the balance of evidence is in favour of this view1 it is probably wiser to retain the distinctive term ,psaronieae on the ground that species of ,psaronius differ in several respects from any recent ferns1 and because of our comparative ignorance in regard to the nature of the fructification4 ,psaronius4 ,this generic name was proposed by ,cotta in his classic work ,die ,dendrolithen#ajed4 ,the stems so named1 formerly included by ,sprengel#ajee in the genus ,endogenites1 had long been familiar as petrified fossils4 ,most of the specimens described by the earlier writers were obtained from ,lower ,permian rocks in the neighbourhood of ,chemnitz1 ,saxony4 ,the mottled appearance presented by their polished surfaces is said to have given rise to the appellation ,staarsteine 7starling stones71 a term expressing a resemblance1 more or less remote1 to a starling's breast4 ,it has been suggested that this word is a corruption of ,stern ,steine or star stones#ajef1 a descriptive term suggested by the stellate arrangement of the vascular strands in transverse sections of the roots4 ,parkinson#ajeg1 in his ,organic ,remains of a former ,world1 speaks of these stems as starry stones4 ,the history of our knowledge prior to #ahed is summarised by ,stenzel4 ,at first compared with corals or the stems of sea-lilies1 ,psaronii were recognised by ,sprengel1 who first used a lens in the examination of the fossils1 as fern stems most nearly allied to those of recent ,cyatheaceae4 ,by other authors1 e4g4 ,schlotheim and ,sternberg1 they were referred to ,palms1 and by ,brongniart considered to be the lower portions of ,lycopodiaceous 7,lepidodendron7 stems4 ,corda and many subsequent authors selected the ,marattiaceae as the most closely allied family among existing plants4 ,psaronius is represented by specimens obtained from the ,lower ,permian of ,saxony and ,upper ,carboniferous rocks in ,central ,france1 also from ,bohemia1 ,brazil and ,north ,america4 ,as yet a few fragments only have been found in the ,english ,coal-,measures4 ,the genus was recognised by ,williamson#ajeh who described the roots and a small piece of the vascular tissue of a stem which he called ,p4 ,renaulti1 and this type has since been more fully described by ,scott#ajei4 ,the roots of another species have been described by ,butterworth#ajfj as ,p4 ,cromptonensis4 ,it was pointed out in the account of ,lepidodendron that several generic names have been used for the same type of stem in different states of preservation2 in ,psaronius accidents of fossilisation have been responsible for a similar confusion in nomenclature4 ,the name ,psaronius is applied to petrified specimens which1 as a rule1 lack external features4 ,casts or impressions of ,palaeozoic tree-fern stems provided with leaf-scars are described as species of ,caulopteris1 ,megaphyton1 and less commonly as ,ptychopteris 7figs4 #big-bii74 ,the first name is applied to stems exhibiting spirally disposed leaf-scars like those of recent tree-ferns2 in ,megaphyton the scars are distichously arranged1 in two rows1 while ,ptychopteris is applied to decorticated stems4 ,these terms are used for stems belonging to one generic type and possessing the structure of ,psaronius stems4 ,illustration3 ,,fig4 #bie4 ,psaronius stem with roots4 7,much reduced4 ,after ,grand',eury47 ,the researches of ,grand',eury#ajfa led to the discovery that certain ,psaronius stems bore fronds of the ,pecopteris type some of which bore sori of the ,asterotheca or ,scolecopteris type4 ,the same author#ajfb has also contributed many interesting facts1 obtained by an examination of the relation of ,psaronius stems to the sediments of ,french ,coal-fields in which they occur1 in regard to habitat and manner of growth4 ,the specimen represented in fig4 #bie shows a portion of a ,psaronius stem1 the upper part of which illustrates the ,caulopteris state of preservation1 while the lower part is covered by a mass of roots4 ,it is probable1 as ,rudolph#ajfc suggests1 that this rich development of roots1 which gives to an old ,psaronius stem the appearance of an elongated cone1 may have served an important mechanical purpose analogous to the secondary thickening in a ,dicotyledon or a ,conifer4 ,a specimen of ,psaronius ,cottai in the ,hofmuseum1 ,vienna1 is cited in illustration of the enormous breadth of the root-system3 the radii of the stem proper and of the encasing cylinder of roots bear the ratio #ag to #afe4 ,the comparatively frequent occurrence of a lacunar cortex in the roots points to the growth of the stems in swampy ground1 a conclusion in harmony with the evidence afforded by the anatomical features of many other ,palaeozoic genera4 ,psaronius may be briefly defined as follows3-- ,tree-fern stems1 occasionally reaching a height of #ej feet or more1 closely resembling in habit recent tree ferns1 but exhibiting in the structure and arrangement of the vascular system a close agreement with recent ,marattiaceae4 ,leaves1 in such cases where a connexion between fronds and stems is known1 large and highly compound and of the ,pecopteris type1 borne in more or less crowded spirals 7,psaronius polystichi71 in four rows 7,p4 tetrastichi71 or in two opposite rows 7,p4 distichi74 ,leaves deciduous1 leaving a clearly defined oval scar containing the impression of the leaf-trace in the form of an open ,u1 or a closed oval with a small inverted ,v-shaped band a short distance below the upper end of the long axis of the oval 7figs4 #big1 #bih72 in ,megaphyton the alternate scars of the two opposite series are larger and characterised by a different form of meristele4 ,the surface of the cortex below the leaf-scars occasionally shows impressions of pits similar to the lenticel-like organs on recent ,tree-fern stems4 ,the central region of the stem is occupied by a complex system of concentrically disposed steles 7dictyosteles71 which in transverse section present the appearance of flat or curved bands varying in extent and in degree of curvature4 ,the vascular bands consist of xylem surrounded by a narrow zone of phloem2 the xylem is composed either exclusively of tracheae or of tracheae and parenchyma2 the protoxylem in the one instance in which it has been clearly recognised is endarch#ajfd4 ,the steles are embedded in parenchymatous tissue and in some species are associated with mechanical tissue 7e4g4 ,p4 infarctus1 fig4 #bif1 ,a1 ,b74 ,the central or vascular region of the stem may be surrounded externally by a cylinder of mechanical tissue interrupted by outgoing leaf-traces and adventitious roots4 ,the leaf-traces arise as single bundles from an internal stelar band and pursue an obliquely radial course towards the outside1 eventually anastomosing with peripheral cauline steles1 which in some species form with the leaf-traces the outermost zone of the vascular region4 ,the leaf-traces have the form of loops which pass into the petioles as ,v-shaped meristeles or closed oval cylinders4 ,as a leaf-trace passes out compensating strands occupy the foliar gap4 ,the vascular region is surrounded by a parenchymatous cortex1 which in younger plants1 or in the apical region of an older plant1 forms the surface of the stem to which the leaf-stalks are attached4 ,from the peripheral steles1 or from the more external bands of the vascular network1 roots are given off which pass in a sinuous vertical course through the cortex1 appearing on the surface between the leaf-bases4 ,in older stems1 after leaf-fall1 the tissue immediately external to the vascular region produces secondary parenchyma with which the roots become intimately associated by their outermost cells4 ,as a result of the secondary cortical development and the gradual increase in the number of roots invading the cortical tissue from above1 the stem is enclosed by a cylinder of roots and associated parenchymatous tissue of secondary origin4 ,in still older portions of a stem the more external roots are free from the stem-cortex and form a thick felted mantle1 which increases in thickness towards the base of the tree4 ,the roots 7fig4 #bif1 ,e7 are polyarch1 #e-aj groups of xylem alternating with strands of phloem1 and similar in structure to those of recent species of ,marattia and ,angiopteris2 the stele is enclosed by an inner cortex of compact or lacunar tissue containing secretory sacs1 and this is surrounded by a cylinder of mechanical tissue4 ,in one or two instances secondary xylem has been observed wholly or partially enclosing the root-stele#ajfe4 ,illustration3 ,,fig4 #bif4 ,a4 ,psaronius infarctus 7,p1 peripheral steles2 ,l1 leaf-traces74 ,b4 ,p4 infarctus1 longitudinal tangential section through the peripheral region of the stem4 ,c4 ,p4 coalescens4 ,d4 ,p4 musaeformis4 ,e4 ,p4 asterolithus 7root74 7,a--,c1 ,e1 after ,zeiller2 ,d1 after ,stenzel47 ,our knowledge of the anatomy of ,psaronius is based largely on the investigations of ,stenzel considerably extended by ,zeiller's more intensive studies and1 more recently1 by the later work of ,stenzel#ajff and that of ,rudolph4 ,a striking fact1 which has led to various suggestions1 is that in a transverse section of a ,psaronius stem with its encasing cylinder of roots no signs of leaf-traces are met with in the root-region4 ,if the roots simply penetrated the cortex1 as in some recent species of ,lycopodium 7fig4 #abe1 ,a7 or as in ,angiopteris1 we should expect to find leaf-traces in the outer region 7root-cylinder7 of ,psaronius stems4 ,an explanation of the absence of leaf-traces which was suggested by ,stenzel1 is that the cortical zone formed a comparatively narrow band in the young leaf-covered stem2 after leaf-fall it became the seat of active growth in its inner layers and so produced a constantly widening zone of secondary parenchyma1 which pushed the superficial cortical tissue with the leaf-bases or leaf-scars farther out until it was exfoliated4 ,farmer and ,hill#ajfg find it difficult to accept this explanation2 but1 as ,rudolph shows1 the radial arrangement of the cortical cells between the adventitious roots and their elongation in a radial direction are arguments in support of the secondary nature of the cortical zone4 ,in sections of the adventitious roots of ,psaronius ,renaulti figured by ,williamson#ajfh1 the spaces between the cylindrical roots are partially occupied by cell-filaments which1 at first sight1 suggest root-hairs2 it may well be1 as ,rudolph suggests1 that these felted hairs represent the outermost and looser part of the growing secondary cortex which gradually passes into the covering mass of free extra-cortical roots4 ,as ,stenzel#ajfi has shown1 slender stems of ,zygopteris 7 ,ankyropteris7 are occasionally met with growing through the web of ,psaronius roots4 ,psaronius infarctus ,unger4 ,fig4 #bif1 ,a1 ,b4 ,this species1 which ,zeiller#ajgj has investigated from sections of ,unger's material1 illustrates a type in which the vascular tissue is very richly developed and forms crowded concentric series of curved plates associated1 in the more peripheral series1 with bands of mechanical tissue4 ,the outermost part of the vascular region consists of 7i7 a series of loops or variously curved bands of conducting tissue representing leaf-traces at different stages in their outward course1 7ii7 a series of similar vascular strands 7peripheral steles of ,zeiller7 confined to the stem 7cauline7 and from which roots are given off1 and 7iii7 bands of mechanical tissue associated with the leaf-traces and peripheral steles4 ,the peripheral steles 7fig4 #bif1 ,a1 ,b1 p7 form anastomoses with the leaf-traces and contribute to their formation4 ,the form of some of the vascular bands in the section of ,psaronius infarctus shown in fig4 #bif1 ,a1 illustrates the occasional anastomosing of one dictyostele with another3 the different degrees of looping of other bands represent stages in the giving off of leaf-traces which eventually pass out as ,v-shaped meristeles4 ,beyond the leaf-traces and sclerenchymatous bands the section consists of transverse sections of adventitious roots4 ,the surface-features of ,psaronius infarctus are probably represented1 as ,zeiller points out1 by the cast described by ,lesquereux as ,caulopteris peltigera 7fig4 #bih1 ,a74 ,illustration3 ,,fig4 #big4 ,pecopteris ,sterzeli3 a1 pinnule4 7,after ,renault and ,zeiller4 nat4 size47 ,the ,psaronius shown in fig4 #big is one of the few examples illustrating the connexion between fronds and stem4 ,the leaf 7,pecopteris ,sterzeli ,zeill4 and ,ren4#ajga is quadripinnate and is described as reaching a length of at least #c metres2 the ultimate segments are entire or lobed4 ,the stem is characterised by elliptical scars1 #f-h cm4 x #ce-d cm41 with leaf-traces like those in ,caulopteris peltigera4 ,the fronds of ,pecopteris ,pluckeneti1 a ,pteridosperm1 bear a very close resemblance to those of ,p4 ,sterzeli1 which are as yet known only in a sterile state4 ,psaronius brasiliensis ,unger1 a species founded by ,unger on a piece of silicified stem acquired by ,martius in ,brazil and now in the ,rio ,museum1 is a good example of a tetrastichous species4 ,solms-,laubach#ajgb has recently told the history of this type1 which is represented by sections1 cut from the ,rio stem1 in several ,european collections4 ,a well-preserved section in the ,british ,museum is figured by ,arber#ajgc in his catalogue of the ,glossopteris flora and by other authors4 ,scott gives a concise description of the species in his ,studies in ,fossil ,botany#ajgd4 ,the roots of ,p4 brasiliensis are stated by ,pelourde#ajge to have a lacunar cortex4 ,psaronius musaeformis ,corda#ajgf4 ,fig4 #bif1 ,d4 ,this species from the ,lower ,permian of ,chemnitz and the ,coal-,measures of ,bohemia affords an example of the distichous type in which the leaves are borne in two rows4 ,the vascular bands1 as seen in a section of the dictyosteles1 occur in regular parallel series4 ,the stelar region is separated from the cylinder of encasing roots by a sclerenchymatous sheath1 broken at intervals where roots pass out from the vascular region4 ,psaronius coalescens#ajgg 7fig4 #bif1 ,c7 illustrates a somewhat different arrangement of vascular tissue which approaches more closely to the polycyclic structure characteristic of such recent ferns as ,matonia and ,saccoloma4 ,a still closer resemblance to the solenostelic type is seen in ,psaronius ,renaulti from the ,lower ,coal-,measures of ,england which ,scott#ajgh describes as characterised by a single annular stele1 interrupted only by the exit of leaf-traces4 ,as he points out1 it is noteworthy that this species is distinguished by the simplest form of stele met with in the genus2 it is the oldest species and may be regarded as the most primitive representative of the genus ,psaronius so far discovered4 ,illustration3 ,,fig4 #bih4 ,a4 ,caulopteris peltigera4 ,b4 ,megaphyton insigne4 7,after ,grand',eury47 ,much reduced4 ,psaronius stems preserved as casts showing surface-features1 or in a decorticated state4 i4 ,caulopteris4 ,this generic name was instituted by ,lindley and ,hutton#ajgi for tree-fern stems from the ,english ,coal-,measures showing circular or oval scars arranged quincuncially4 ,the vascular tissue of the petiole is represented by a ,u-shaped impression on the scar1 the ends of the ,u being incurved1 or by a closed oval ring with a wide-open and inverted ,v near its upper end4 ,the surface between the leaf-scars bears the impression of adventitious roots4 ,caulopteris is represented1 in the ,upper ,coal-,measures of ,england1 by ,c4 anglica#ajhj ,kidst4 ,the species ,c4 peltigera 7fig4 #bih1 ,a71 originally described by ,brongniart as ,sigillaria1 illustrates the closed form of leaf-trace and1 as ,zeiller suggests1 it is the cast of a ,psaronius stem which possessed a vascular system on the same plan as that of ,p4 infarctus4 ,c4 ,saportae#ajha illustrates the open ,u-shaped type of petiole stele4 ,caulopteris peltigera has scars measuring #f-i by #d-f cm42 it occurs in the ,commentry ,coal-field of ,france in association with the fronds known as ,pecopteris cyathea1 a species which ,kidston regards as identical with ,p4 arborescens#ajhb4 ii4 ,megaphyton4 ,the first use of this name was by ,artis#ajhc1 who gave it to a long flattened cast1 ,megaphyton frondosum1 found in ,carboniferous strata in ,yorkshire1 characterised by two vertical rows of large scars and by impressions of sinuous roots4 ,kidston records the genus from the ,middle and ,upper ,coal-,measures of ,britain4 ,a good example of this type of cast is afforded by ,m4 ,mc,layi ,lesq4#ajhd from the ,coal-,measures of ,north ,america1 which has been recognised in ,european ,carboniferous rocks4 ,the leaf-scars are rounded or oval1 broader than high2 the vascular impression has the form of a closed ring 7#e-h #c-f cm471 more or less circular and with a tendency to a rectangular outline1 characterised by a deep inverted ,u-shaped sinus in the middle of the lower surface and by a ,w-shaped impression of an internal strand 7fig4 #bih1 ,b7#ajhe4 iii4 ,ptychopteris4 ,this generic name1 instituted by ,corda#ajhf1 is applied to decorticated stems of ,psaronius1 the surface of which is that of the vascular region on which the form of the leaf-scars is more or less clearly defined4 ,the scar-areas are limited by an impression of the sclerenchymatous sheath enclosing the leaf-meristele1 and internal to this is the impression of the leaf-trace4 ,in some specimens a layer of coaly material which represents the carbonised cortex and adventitious roots covers the ,ptychopteris cast4 ,the ,ptychopteris cast represented in fig4 #bii shows the decorticated surface of part of a long stem on which the leaf-scars are arranged as in ,megaphyton4 ,an example of ,ptychopteris is figured by ,fontaine and ,white#ajhg from ,virginia as ,caulopteris gigantea4 ,illustration3 ,,fig4 #bii4 ,ptychopteris4 nat4 size4 ,from the ,middle ,coal-,measures of ,lancashire4 7,the ,manchester ,museum47 ,illustration3 ,,fig4 #cjj4 ,dicksonia antarctica 7half of stem in transverse section73 st1 stele2 s1 sclerenchyma4 ,position of ,psaronius4 ,a comparison of ,psaronius with the ,marattiaceae and other recent ferns leads to the conclusion that1 on the whole1 the evidence is in favour of the view usually held1 namely that this genus is more closely related to the ,marattiaceae than to any other recent ferns4 ,it is1 however1 important not to overlook the differences between ,psaronius and recent genera of ,marattiaceae1 or the resemblances between the extinct genus and the ,cyatheaceae4 ,in habit ,psaronius agrees closely with recent tree-ferns2 in the vascular system and in the sequence of events connected with the production of leaf-traces1 there are striking resemblances between ,psaronius and the ,cyatheaceous fern ,saccoloma adiantoides 7 ,dicksonia ,plumieri ,hook47 as described by ,mettenius#ajhh4 ,the piece of stem of ,dicksonia antarctica represented in fig4 #cjj exhibits a fairly close agreement with species of ,psaronius1 e4g4 ,p4 infarctus 7fig4 #bif1 ,a1 ,b74 ,moreover1 the peripheral steles1 which ,zeiller has shown are confined to the stem and play an important part in the production of the roots and in the anastomoses with leaf-traces1 are not represented in any ,marattiaceous fern2 on the other hand1 they are comparable with the accessory strands met with in stems of recent ,cyatheaceous tree-ferns#ajhi 7cf4 fig4 #bdj74 ,the complex system of concentric dictyosteles is a feature more closely matched in ,angiopteris 7,marattiaceae7 than in any ,cyatheaceous genus1 the chief difference being in the more band-like form of the steles in ,psaronius1 though in a stem of ,angiopteris figured by ,mettenius we see a close approach to the extinct type4 ,the position of the protoxylem has unfortunately not been clearly defined in ,psaronius stems1 but in ,p4 ,renaulti it is stated by ,scott#ajij to be endarch1 a position which some of the protoxylem strands occupy in ,angiopteris#ajia4 ,the occurrence of large sieve-tubes described by ,scott in ,p4 ,renaultii is another feature shared by recent ,marattiaceae4 ,in many of the continental species of ,psaronius the phloem has not been preserved1 and our knowledge of this tissue is comparatively meagre4 ,in the ,marattiaceae the roots arise mainly from the inner portions of the stele1 while in ,psaronius they are usually formed from the external vascular bands4 ,the formation of secondary cortical tissue is a peculiarity of ,psaronius2 on the other hand1 if ,butterworth#ajib is correct in referring to that genus the roots with secondary xylem1 which he describes as ,p4 ,cromptonensis1 a comparison may be made with the occurrence of secondary tracheae in the stem steles of ,angiopteris#ajic4 ,the absence of mechanical tissue in the stem of ,angiopteris is in contrast with its occurrence in the fossil stems and in recent tree-ferns2 but this is a character of secondary importance and one which can be readily explained by the difference in habit between ,angiopteris and ,psaronius4 ,the roots of ,psaronius1 more especially as regards the stelar structure1 are in close agreement with those of ,marattiaceae4 ,the reference to ,marattiaceae of the great majority of fertile fern-like fronds from ,permian and ,carboniferous rocks constituted a strong a priori argument in favour of including ,psaronius stems in the same family1 especially when it was known that leaves with ,marattiaceous synangia were borne by species of this genus4 ,it is1 however1 well to remember the change in our views as to the dominance of ,marattiaceae in ,palaeozoic floras consequent on the discovery of the ,pteridosperms4 ,the association of fronds bearing ,asterotheca and ,scolecopteris types of fructification with ,psaronius stems recorded by ,grand',eury#ajid is a point in favour of the ,marattiaceous affinity of this extinct genus1 but it is not impossible that ,psaronius stems bore fronds which produced ,pteridosperm organs of reproduction4 ,in this connexion the specimen represented in fig4 #big is of interest1 as the fronds 7,pecopteris ,sterzeli7 borne on the ,psaronius stems are hardly distinguishable from the seed-bearing leaves known as ,pecopteris ,pluckeneti4 ,the position of ,psaronius may be best expressed by assigning it to a separate family1 the ,psaronieae1 as advocated by ,stenzel1 and by regarding it as one of the many instances of a generalised type which in the sum of its characters approaches most nearly to the ,marattiaceae4 ,,chapter ,,xxiv4 ,ophioglossales 7,fossil74 ,the fossils hitherto classed with the ,ophioglossales are not such as afford any satisfactory evidence in regard to the past history or phylogeny of the group4 ,in the generalised class of ,palaeozoic ferns1 the ,botryopterideae1 we find certain characters suggesting comparison with recent members of the ,ophioglossaceae1 but no trustworthy records of these eusporangiate ferns are furnished by the older plant-bearing strata4 ,illustration3 ,,fig4 #cja4 ,rhacopteris sp41 ,ballycastle1 ,ireland4 ,from a specimen in the ,manchester ,museum4 ,m4,s4 ,the genus ,rhacopteris 7fig4 #cja71 characteristic of the ,culm flora1 has been compared with ,botrychium1 but on grounds which are wholly inadequate4 ,the species ,r4 paniculifera ,stur#ajie is characterised by a stout rachis bearing two rows of laterally attached rhomboidal or subtriangular segments with a more or less deeply lobed margin and spreading veins4 ,the rachis branches distally into two arms1 and these are again symmetrically subdivided into fertile axes bearing clusters of small spherical bodies #a mm4 broad1 which ,stur speaks of as exannulate sporangia similar to those of ,botrychium4 ,he includes the species in the ,ophioglossaceae4 ,as ,zeiller#ajif pertinently remarks1 ,rhacopteris differs essentially in habit from any recent member of this family4 ,rhacopteris also includes species characterised by leaflets deeply dissected into linear segments2 an example of this form is represented by ,rhacopteris flabellata 7,tate7 recorded by ,kidston#ajig from rocks of ,calciferous ,sandstone age in ,flintshire4 ,the specimen described by ,renault#ajih from the ,carboniferous rocks of ,autun as ,ophioglossites antiqua is equally unconvincing3 it consists of a carbonised fragment1 #g cm4 #ae cm41 regarded as part of a fertile lamina characterised by a vertical series of transversely elongated slits1 #g mm4 wide1 some of which1 on slight magnification1 are seen to contain a mass of small orange-yellow granulations4 ,the slits are compared with the surface-openings of the sunken sporangia of ,ophioglossum1 and the yellow bodies are identified as spores4 ,the material is too imperfect to justify the use of the name ,ophioglossites4 ,noeggerathia4 ,this genus of uncertain position may be briefly described here1 though it has little claim to recognition as a representative of the ,ophioglossales4 ,it is characteristic of ,lower ,carboniferous rocks and is compared by ,stur#ajii with recent ,ophioglossaceae4 ,noeggerathia foliosa ,sternb4 7fig4 #cjb7 may be cited as a typical example of the genus4 ,it consists of an axis bearing ovate leaves with numerous spreading veins4 ,the upper part of the axis forms a spike composed of fertile leaves in the form of transversely oval bracts #b cm4 broad with a serrate edge bearing on the upper face several sporangia 7#c #d mm47 in some of which spores have been seen 7fig4 #cjb1 ,b1 ,c74 ,in another form described by ,weiss#aajj the bracts bear a greater number of sporangia characterised by the presence of an arillus-like basal ring4 ,illustration3 ,,fig4 #cjb4 ,noeggerathia foliosa4 7,after ,stur2 ,a1 reduced47 ,b1 ,fertile leaf2 ,c1 ,sporangium4 ,geinitz#aaja1 who first described fertile specimens of ,noeggerathia1 placed the genus in the ,gymnosperms1 and ,o4 ,feistmantel#aajb was in favour of this view4 ,c4 ,feistmantel#aajc1 who described the small bodies in the sporangia1 suggested comparison with ,schizaeaceae1 and ,weiss#aajd discussed various possibilities1 asking but not answering the question1 are the so-called sporangia rightly so named or are they fruits8 ,potoni#aaje places the genus in the ,cycadofilices4 ,an important feature is the occurrence of the sporangia on the upper face of the bracts as in ,lycopodiales and ,sphenophyllum1 but in other respects ,noeggerathia bears no resemblance to these two groups4 ,sterile examples of the genus are similar in habit to ,rhacopteris1 but in the latter genus the leaves or leaflets are laterally attached and not obliquely inserted4 ,further1 we may assume that in ,rhacopteris the segments are leaflets of a compound leaf1 whereas in ,noeggerathia they are probably single leaves4 ,we must leave the position of this ,lower ,carboniferous genus undecided1 merely expressing the opinion that it is perhaps more nearly allied to the ,cycads than to any other group4 ,illustration3 ,,fig4 #cjc4 ,chiropteris ,zeilleri1 ,sew4 ,from a specimen in the ,british ,museum 7v4 #cbfh74 ,nat4 size4 ,the plant figured by ,lindley and ,hutton from the ,english ,coal-,measures as ,noeggerathia flabellata1 which some authors quote as a species of ,noeggerathia1 is generally recognised as a ,psygmophyllum and placed with some hesitation in the ,ginkgoales4 ,chiropteris4 ,this genus was founded by ,kurr on a leaf characterised by anastomosing venation from ,keuper beds near ,stuttgart4 ,a resemblance in form and venation to the leaves of recent species of ,ophioglossum led authors to suggest the inclusion of ,kurr's specimen in the ,ophioglossaceae4 ,we have1 however1 no justification for considering ,chiropteris as a member of this family2 it may be a fern1 and that is all that can be said4 ,the leaf represented in fig4 #cjc is the type-specimen of a ,south ,african ,rhaetic species ,chiropteris ,zeilleri#aajf4 ,the genus is recorded also from ,rhaetic rocks in ,queensland4#aajg ,newberry#aajh describes some leaves from the ,lower ,cretaceous of ,montana as species of ,chiropteris3 one of his types1 ,c4 spatulata1 is almost certainly a ,sagenopteris1 similar to ,s4 ,phillipsi 7figs4 #cbg1 #cbh7 or ,s4 ,mantelli4 ,a second species1 ,c4 ,williamsii1 is probably not generically identical with the specimen represented in fig4 #cjc4 ,,chapter ,,xxv4 ,coenopterideae4 ,i4 ,botryoptereae4 ,,ii4 ,zygoptereae4 ,the term ,botryopterideae1 first used by ,renault1 has been applied to a group of ,palaeozoic ferns ranging from the ,lower ,carboniferous to the ,permian and containing several genera1 the distinguishing features of which are supplied by the anatomical structure of the stems or1 in many cases1 by that of the petiolar vascular strand4 ,scott#aaji subdivides the ,botryopterideae into the ,botryopteris and the ,zygopteris sections4 ,in an admirable monograph recently published by ,paul ,bertrand#aaaj considerable changes are proposed in current nomenclature2 he substitutes the name ,inversicatenales for ,botryopterideae1 a designation1 which as ,scott remarks1 is 8probably too technical to command general acceptance40 ,a more serious criticism is that the name ,inversicatenales has reference to a character 7the inverse curvature of the leaf-trace in relation to the axis of the stem7 which is by no means universal in the group#aaaa4 ,in the following account1 necessarily incomplete1 the generic terminology of ,bertrand is adopted1 but this decision does not carry with it any obligation to accept the name ,inversicatenales4 ,we may speak of the types of ,palaeozoic ferns dealt with in the following pages as members of a group differing in many respects from any existing genera of the ,filicales1 and exhibiting the characteristics associated with generalised plants4 ,williamson1 as early as #ahhc1 spoke of ,renault's ,botryopterideae as comprising 8altogether extinct and generalised0 types#aaab4 ,for these generalised ,palaeozoic ferns ,i propose to use the name ,coenopterideae#aaac4 ,this term may be adopted in a wider sense than ,renault's name ,botryopterideae4 ,the name ,primofilices proposed by ,arber#aaad might be employed1 but the implication which it carries is an argument against its adoption4 ,we have not yet reached a stage in the investigation of extinct types at which we are able to recognise what are actually primary or primitive ferns4 ,the search for origins will continue2 as new discoveries are made our point of view shifts and the primitive type of to-day may to-morrow have to take a higher place4 ,the epithet primitive or primary is in reality provisional3 to adopt such a name as ,primofilices suggests a finality which has not been1 or is likely to be1 achieved4 ,the true ancestral type--the ,urform--which we strive to discover eludes the pursuer like a will-o'-the-wisp4 ,seeing that the number of true ferns of ,palaeozoic age has been recently considerably reduced and is likely to suffer further reduction1 the consideration of such undoubted ,carboniferous and ,permian examples of the ,filicales as are left acquires a special importance4 ,in the first place it is natural to ask whether the ,palaeozoic ferns include any types which1 if not themselves ancestral forms1 may serve to indicate the probable lines of evolution of existing families4 ,it is probable that in the near future our knowledge of the ,coenopterideae will be considerably extended2 as yet we possess meagre information in regard to those characters on which most stress has generally been laid in the classification of recent ferns1 namely the structure of the spore-bearing organs4 ,the sporangia of ,diplolabis and ,stauropteris 7figs4 #cji1 ,a2 #cbb7 are exannulate2 in the former genus they occur in sori or synangia consisting of a small number of sporangia1 while in the latter they are borne singly at the tips of ultimate ramifications of a highly compound leaf4 ,the resemblance of the synangium of ,diplolabis to that of ,kaulfussia 7fig4 #bde1 ,c7 is not shared in an equal degree by the sporangia of ,stauropteris1 which are in some respects comparable with those of the ,ophioglossaceae4 ,in the ,zygoptereae1 or at least in the case of such fertile fronds as are known1 and in ,botryopteris 7fig4 #cai71 the sporangia occur in groups1 and the pedicel of each sporangium is supplied with vascular tissue as in ,helminthostachys4 ,another characteristic of the sporangia of the extinct types is the possession of an annulus several cells in breadth1 a peculiarity which supplies a point of contact with the ,osmundaceae4 ,in the sporangia of ,kidstonia we have a similar though not an identical type 7fig4 #bef1 ,e1 p4 #cdj74 ,so far1 then1 as the evidence afforded by sporangial characters is concerned1 it points to comparison with the ,ophioglossaceae1 the ,osmundaceae1 and the ,marattiaceae4 ,when we compare the steles of the stems we find a wide range of structure4 ,all the genera agree in being monostelic2 in ,tubicaulis and ,grammatopteris the protoxylem is exarch1 in ,botryopteris it is internal1 while the foliar strand of ,stauropteris and the stele of ,ankyropteris corrugata are mesarch4 ,the axillary branching of species of ,ankyropteris suggests comparison with the ,hymenophyllaceae4 ,the investigation of the vascular system of the petioles has afforded results which in the hands of ,p4 ,bertrand have led to conclusions in regard to inter-relationships4 ,we must1 however1 not overlook the danger of attributing can excessive importance to this single criterion and of neglecting the facts of stem anatomy4 ,i4 ,botryoptereae4 ,grammatopteris4 ,renault instituted this genus for petrified stems from the ,permo-,carboniferous beds of ,autun4 ,grammatopteris ,rigolloti#aaae1 the type-species1 is represented by a fragment1 #ab-ae mm4 in diameter1 surrounded by crowded petioles characterised by a vascular strand in the form of a short and comparatively broad plate with the smallest tracheae at each end4 ,the solid xylem of the stem stele 7protostele7 has peripheral groups of protoxylem4 ,nothing is known as to the form of the leaves1 but sporangia similar to those of ,etapteris 7,zygopteris7 were found in association with the stem4 ,it is possible1 as ,p4 ,bertrand suggests1 that ,renault's species may be the stem of a ,tubicaulis4 ,tubicaulis4 ,tubicaulis solenites 7,sprengel7#aaaf4 ,fig4 #cjd4 ,this species from the ,lower ,permian of ,saxony has been fully described by ,stenzel#aaag4 ,it is characterised by a very slender erect stem bearing numerous spirally disposed leaves associated with adventitious roots2 the single stele 7protostele7 consists exclusively of tracheae1 described as intermediate between the scalariform and reticulate type1 surrounded by phloem4 ,leaf-traces are given off from the periphery of the stele where groups of smaller elements occur2 these have the form of a wide-open ,u-shaped strand with the base of the ,u facing the axis of the stem4 ,as the trace passes out towards the leaves1 the ends of the ,u become more or less incurved4 ,the stem is said to reach a metre in length and to bear compound fronds a metre long4 ,the orientation of the leaf-trace with its concavity turned outwards is in striking contrast to the relation between leaf-trace and stem in recent ferns4 ,illustration3 ,,fig4 #cjd4 ,tubicaulis solenites4 7,from ,tansley1 after ,stenzel47 ,stem and petioles3 the latter numbered in the order of their age4 ,tubicaulis ,sutcliffii1 ,stopes#aaah4 ,in this species the vascular axis1 #b mm4 in diameter1 is almost cylindrical and of the protostelic type with the protoxylem 8near to or at the edge03 the tracheae are scalariform or reticulate4 ,the leaf-traces1 when first separated from the edge of the stele1 are oval and gradually assume the curved form seen in ,t4 solenites 7fig4 #cjd7 with the convex side towards the axis of the stem4 ,the transition from the scalariform to the reticulate type of pitting on the tracheal walls referred to by ,miss ,stopes has also been noticed in some recent ferns 7e4g4 ,helminthostachys7 and in ,sigillaria 7fig4 #bjj1 ,c1 p4 #bab74 ,the fact that the scalariform type of pitting is practically universal in the xylem of recent ferns1 would seem to show that this character has been acquired in the course of evolution and retained in preference to the reticulate form characteristic of several ,palaeozoic species4 ,the distinction between the two methods of pitting is one of little phylogenetic importance4 ,botryopteris4 ,this genus1 founded by ,renault on a specimen from ,autun1 is represented in the ,lower ,coal-,measures of ,england by ,botryopteris hirsuta 7 ,rachiopteris hirsuta ,will471 ,b4 ramosa 7 ,r4 ramosa ,will4#aaai7 7fig4 #cjf7 and ,b4 cylindrica 7fig4 #cje71 also by ,b4 antiqua 7fig4 #cjg7 from the ,culm of ,pettycur1 ,scotland4 ,an important characteristic of the genus is the solid stele of the stem which agrees with that of ,tubicaulis and ,grammatopteris1 except in the central or peripheral position of the smallest tracheae4 ,botryopteris forensis ,renault#aabj4 ,figs4 #cji1 ,b2 #cai1 ,d-,g4 ,the stem of this species from the ,upper ,carboniferous of ,st tienne is #ag cm4 x #ge mm4 in diameter4 ,the solid stele consists of reticulate tracheae with the smallest elements on the outer edge4 ,the comparatively broad cortex of the type-specimen is traversed by a leaf-trace in an almost vertical course and by vascular strands passing horizontally to roots4 ,the petioles are circular in section and their vascular strand has the form of an in transverse section 7fig4 #cai1 ,g71 the three projecting arms pointing to the axis of the stem4 ,both stem and leaves bore large multicellular hairs1 spoken of by ,renault as equisetiform because of the finely toothed sheaths of which they are composed4 ,the compound fronds had fleshy lobed pinnules with dichotomously branched veins 7fig4 #cji1 ,b72 stomata are said to be confined to the upper surface1 an observation which leads ,renault to describe the plant as aquatic on evidence which is hardly convincing4 ,the pyriform and pedicellate sporangia are borne in groups of two to six on the ultimate divisions of the frond2 the wall is composed of two layers of cells and on one side of the sporangium is an annulus several cells in breadth 7fig4 #cai1 ,d1 ,f74 ,an interesting type of sporangium described by ,oliver#aaba from ,grand',croix in ,france may1 as he suggests1 belong to ,botryopteris forensis2 the differences between ,renault's and ,oliver's specimens being the result of the more perfect preservation of the tissues in the latter4 ,the sporangium described by the ,english author is circular in section and measures #jfe #jec mm42 the wall is in part composed of a single layer of cells and in part of two to three layers1 a character recalling the 8annulate0 sporangia of ,botryopteris4 ,between the spore-mass and the wall is an interrupted ring of short tracheal elements similar to the xylem-mantle which occurs at the periphery of the nucellus of certain ,palaeozoic gymnospermous seeds4 ,in the absence of proof of a connexion between this sporangium and ,botryopteris it is convenient to use the generic name ,tracheotheca subsequently proposed by ,oliver#aabb4 ,in the recent ferns ,helminthostachys and ,botrychium1 and1 as ,oliver notices1 in the microsporangia of the ,australian ,cycad ,bowenia spectabilis1 vascular strands extend almost to the sporogenous tissue1 but the fossil sporangium is unique in having a tracheal layer in immediate contact with the spores4 ,these xylem elements may1 as ,oliver suggests1 have served the purpose of conveying water to the ripening spores4 ,botryopteris hirsuta 7,will47#aabc4 ,this ,english species has a slender axis bearing numerous leaves with petioles equal in diameter to the stem4 ,the surface of the vegetative organs bears large multicellular hairs4 ,the leaf-traces resemble those of ,b4 forensis1 but the projecting teeth which terminate in protoxylem elements are less prominent than in the ,french species2 the petioles were named by ,felix ,rachiopteris tridentata#aabd4 ,as a leaf-trace passes into the stele of the stem the three protoxylem strands unite and take up an internal position in the solid stele4 ,the stele may1 therefore1 be described as endarch4 ,the small tracheae at the edge of the stele supply the xylem strands of adventitious roots4 ,sporangia similar to those of ,b4 forensis have been found in association with the ,english species4 ,botryopteris cylindrica 7,will474 ,fig4 #cje4 ,a plant originally described by ,williamson#aabe from the ,lower ,coal-,measures of ,england as ,rachiopteris cylindrica 7fig4 #cje7 and afterwards more fully dealt with by ,hick#aabf1 has a slender stem with a cylindrical stele characterised by well-defined central protoxylem elements in one or two groups4 ,the leaf-traces are semi-lunar in section with the protoxylem on the flatter side4 ,the stele of ,botryopteris cylindrica 7fig4 #cje1 ,a7 is more cylindrical in section than that of ,b4 ramosa 7fig4 #cjf7 and shows more clearly the differentiation into smaller central and larger peripheral tracheae4 ,in the section reproduced in fig4 #cje1 ,b the stele is giving off a branch almost identical in structure with the main vascular axis4 ,scott#aabg1 in referring to the inclusion of this type in the genus ,botryopteris1 expresses the opinion that its habit must have been very different from that of other species1 and he suggests the institution of a new genus4 ,illustration3 ,,fig4 #cje4 ,botryopteris cylindrica 7 #cj74 ,from sections in the ,cambridge ,botany ,school4 ,botryopteris ramosa 7,williamson74 ,fig4 #cjf4 ,this species1 which bears a close resemblance to ,botryopteris hirsuta1 was originally described by ,williamson from the ,lower ,coal-,measures of ,england as ,rachiopteris ramosa#aabh1 the specific name being chosen on account of the numerous and crowded branches given off from the main axis4 ,the section shown in fig4 #cjf1 ,a1 illustrates ,williamson's description of the stem as being 8always surrounded when seen in transverse sections by a swarm of similar sections of the large and small branches1 though of varying shapes and sizes40 ,the stele is composed of a solid and more or less cylindrical rod of xylem tracheae of the reticulate type surrounded by phloem 7figs4 ,a and ,d73 one or more internal groups of smaller protoxylem elements occur in an approximately central position 7fig4 ,a1 px74 ,the stele is in fact endarch like those of ,selaginella spinosa and ,trichomanes reniforme1 a feature which1 as ,tansley#aabi believes1 probably entitles the vascular axis to be considered a primitive form of protostele4 ,in the specimens represented in fig4 #cjf the phloem and inner cortical tissues were almost completely destroyed before petrifaction4 ,the thick-walled outer cortex bears at its periphery numerous multicellular hairs4 ,some of the xylem strands given off from the stele no doubt supplied adventitious roots1 but in most cases the outgoing branches are leaf-traces and the numerous sections of axes of different sizes seen in fig4 ,a point to a repeated subdivision of the crowded fronds4 ,the structure of a petiole is shown in figs4 ,c and ,d4 ,as seen in fig4 ,c1 the oval vascular strand has three protoxylem groups1 px1 on its flatter side2 a well-defined epidermal layer is shown at e in fig4 ,c4 ,fig4 ,b shows at a a section of a leaf-axis in the act of branching and the row of branchlets at b represents a further stage in subdivision4 ,at sp in fig4 ,a the section has cut through a single sporangium characterised by a group of larger 78annulus07 cells on one side of the wall4 ,illustration3 ,,fig4 #cjf4 ,a-,d4 ,botryopteris ramosa2 stem and frond axes4 7,a #g2 ,b #ae2 ,c #bf2 ,d #ac4 ,from sections in the ,cambridge ,botany ,school ,collection47 px1 protoxylem2 sp1 sporangium2 e1 epidermis4 ,this slender fern with its numerous repeatedly branched leaves may perhaps have lived epiphytically on more robust plants4 ,botryopteris antiqua1 ,kidst4 ,fig4 #cjg4 ,this species1 recently described by ,kidston#aacj from the ,culm of ,pettycur near ,burntisland1 is represented by sections of a small stem with a cylindrical stele #jdj mm4 in diameter composed entirely of scalariform tracheae without any recognisable protoxylem4 ,the petioles are larger than the stem2 the meristele 7fig4 #cjg7 is oval with protoxylem elements on the slightly more rounded adaxial face4 ,as ,kidston suggests1 this stem may belong to a scrambling plant which required support to bear its relatively large leaves4 ,an interesting feature is the absence of projecting teeth in the leaf-trace1 a character in marked contrast to the form assumed by the petioles of ,botryopteris forensis 7fig4 #cai1 ,g7 and ,b4 hirsuta4 ,this leads ,kidston to suggest that the vascular strand of the petiole tends 8to become more simple 444 as traced back in geological time40 ,the greater similarity in this species between the stele of the stem and that of the petiole is probably another mark of a more primitive type4 ,illustration3 ,,fig4 #cjg4 ,botryopteris antiqua3 ,petiolar vascular strand4 7,after ,kidston3 #fe47 ,in these three types1 ,grammatopteris1 ,tubicaulis1 and ,botryopteris1 we have monostelic plants1 for the most part of very small size1 with leaf-traces varying in shape from the oblong band-form in ,grammatopteris1 and the oval form of ,botryopteris antiqua1 to the type represented in its most pronounced form by ,b4 forensis4 ,in several species the stem stele is endarch4 ,our knowledge of the leaves is very meagre3 in ,b4 forensis they were repeatedly branched and apparently bore small fleshy pinnules2 the sporangia1 though differing from those of recent ferns1 may be compared with the spore-capsules of ,osmundaceae as regards the structure of the annulus4 ,the abundance of hairs on the stems and leaves of some species1 the tracheal sheath in the sporangium described by ,oliver#aaca as ,tracheotheca 7 ,botryopteris871 and the apparent absence of a large well-developed lamina1 may perhaps be regarded as evidence of xerophilous conditions4 ,,ii4 ,zygoptereae4 ,corda#aacb proposed the generic name ,zygopteris for petrified petioles from the ,permian of ,saxony1 included by ,cotta in his genus ,tubicaulis1 which he named ,t4 primarius4 ,corda's genus has been generally used for petioles of ,palaeozoic ferns characterised by a vascular strand having the form of an ,h in transverse section 7fig4 #cjh1 ,d74 ,since the generic name was instituted1 information has been obtained in regard to the nature of the stems which bore some of the petioles of the ,zygopteris type2 and for other species of ,zygopteris1 the stems of which are still unknown1 new generic names have been proposed4 ,p4 ,bertrand#aacc retains ,zygopteris for one species only1 ,z4 primaria4 ,fig4 #cjh1 ,d1 shows the character of the petiolar vascular strand2 the chief points are the comparatively long cross-pieces 7antennae of ,p4 ,bertrand7 inclined at an angle of #de to the plane of symmetry of the petiole axis1 and the groups of protoxylem elements shown by the white patches in fig4 ,d4 ,in this as in other members of the ,zygoptereae the main rachis of the leaf gives off four sets of branches in pairs alternately from the right and left side of the primary vascular axis4 ,this method of branching of the stele in the primary rachis of several members of the ,coenopterideae shows that the fronds bore pinnae laterally disposed1 in some cases in one row and in others in two rows on each side of the rachis4 ,in a typical fern frond1 as represented by recent and most fossil species1 branching of the rachis occurs in the plane of the frond1 that is in the plane represented by the horizontal arm of xylem in ,zygopteris primaria connecting the two antennae or cross-pieces4 ,in the ,zygoptereae the branches from the petiole vascular axis lie in a plane at right angles to that of the frond2 they lie in the transverse and not in the horizontal plane4 ,the two strands shown in fig4 #cjh1 ,b1 #d1 have been formed by the division of a single strand1 #c1 in the transverse plane 7i4e4 in the plane of the paper74 ,as ,tansley#aacd points out1 a type of branching superficially similar to1 though not identical with this1 is seen in some recent species of ,gleichenia and ,lygodium4 ,in this connexion it is worthy of note that a fern figured by ,unger from ,thuringia as ,sphenopteris petiolata ,goepp#aace bears pinnae in two rows on the rachis which are characterised by repeated branching and by a very narrow lamina or by slender naked axes2 the occurrence of this form of frond in rocks containing ,clepsydropsis antiqua 7fig4 #cjh1 ,a7 suggests a possible connexion between the petrified rachis and the impressions of the leaves4 ,illustration3 ,,fig4 #cjh4 ,a4 ,clepsydropsis antiqua4 ,b4 ,etapteris ,scotti4 ,c4 ,diplolabis forensis4 ,d4 ,zygopteris primaria4 ,e-,g4 ,stauropteris oldhamia4 ,the white patches in the xylem in figs4 ,b-,g mark the position of protoxylem elements4 7,a1 after ,unger2 ,b-,g1 after ,p4 ,bertrand47 ,illustration3 ,,fig4 #cji4 ,a4 ,diplolabis forensis4 ,b4 ,botryopteris forensis4 ,c1 ,d4 ,corynepteris coralloides4 ,e4 ,schizopteris 7,etapteris7 pinnata4 7,a1 ,b1 after ,renault2 ,c1 ,d1 after ,zeiller2 ,e1 after ,renault and ,zeiller47 ,the vascular strand of the rachis of ,zygopteris primaria 7fig4 #cjh1 ,d7 is simpler than that of most of the ,zygoptereae and exhibits a close resemblance to the type of strand described by ,renault as ,diplolabis 7fig4 #cjh1 ,c74 ,diplolabis4 ,renault#aacf instituted this genus for two species from the ,culm beds and ,coal-,measures of ,france based on the structure of the petioles4 ,the stems are unknown4 ,the main rachis has a stele similar to that of ,zygopteris primaria1 but distinguished by its greater similarity1 in transverse section1 to an ,x rather than to the letter ,h3 the long transverse bar in ,zygopteris is here much reduced in size4 ,the petiole of ,diplolabis forensis#aacg ,ren4 7fig4 #cjh1 ,c7 has a diameter of #ae-b cm4 ,from the antennae a pair of small bundles is given off alternately from the right and left side1 as in ,zygopteris2 the members of each pair coalesce after leaving the antennae and then separate to pass into the lateral branches of the frond4 ,the position of the protoxylem and the formation of the lateral xylem strands previous to their separation are shown in fig4 #cjh1 ,c4 ,on the side of the vascular strand shown in fig4 ,c1 #b1 the two lateral extensions of the antennae are converging towards one another previous to their separation and subsequent union4 ,the ovoid sporangia occur in groups of three to six and are coalescent below with a central receptacle2 they have no annulus1 but the cells on the side next the receptacle are smaller than those on the external wall 7fig4 #cji1 ,a74 ,the synangial form of the sorus suggests comparison with ,marattiaceae4 ,the species described by ,renault from the ,culm of ,esnost is regarded by ,p4 ,bertrand as identical with that described by ,solms1 from the ,culm of ,falkenberg1 as ,zygopteris ,roemeri#aach4 ,diplolabis is compared by ,p4 ,bertrand with ,metaclepsydropsis1 the generic name given to the ,lower ,carboniferous petiole described by ,williamson as ,rachiopteris duplex#aaci4 ,mr ,gordon has recently described in a preliminary note a new type of stem stele under the name ,zygopteris pettycurensis from the ,lower ,carboniferous plant bed of ,pettycur#aadj3 he regards the petioles attached to the stem as identical with ,zygopteris ,roemeri ,solms-,laubach#aada4 ,this species1 founded by ,solms-,laubach on petioles only1 is placed by ,bertrand#aadb in the genus ,diplolabis and regarded as identical with ,d4 esnostensis ,ren4 ,the stele found by ,mr ,gordon may therefore be assigned to the genus ,diplolabis3 it includes two regions composed exclusively of tracheae and is cylindrical in transverse section4 ,the inner xylem zone consists of short1 square-ended1 reticulately pitted elements and the outer zone is composed of long and pointed conducting tracheae4 ,the scalariform protoxylem elements are situated between the two metaxylem zones4 ,as ,mr ,gordon says3 this type of stem occupies a position 8in the ,zygopteroid alliance0 corresponding to that which ,thamnopteris ,schlechtendalii 7p4 #cbi7 occupies in the ,osmundaceous series4 ,the discovery of this stem supplies another link between the two fern groups1 ,osmundaceae and ,coenopterideae4 ,pelourde#aadc has described an imperfectly preserved vascular strand from a locality near ,autun as the type of a new genus ,flicheia esnostensis4 ,mr ,gordon has pointed out to me that this is a partially rotted petiole of ,diplolabis esnostensis 7 ,zygopteris ,roemeri74 ,in their recent account of fossil ,osmundaceous genera1 ,kidston and ,gwynne-,vaughan#aadd speak of the central parenchyma of the existing medullated stele as being derived from tracheal tissue4 ,they add that if the ,zygopteroid line of descent is at all close to the ,osmundaceous1 we must be prepared for the existence of a ,zygopteris with a solid xylem like that of ,thamnopteris3 8such a discovery1 in fact1 we hopefully anticipate#aade40 ,the new ,pettycur stem amply justifies this prophecy4 ,it is noteworthy that ,mr ,gordon's stem affords an instance of the occurrence of a type of stele1 similar in its cylindrical form and in the absence of parenchyma to that of ,botryopteris1 in a plant bearing leaves characterised by the ,zygopteris type of vascular strand4 ,metaclepsydropsis duplex 7,will47 fig4 #caj1 ,a#aadf4 ,rachiopteris duplex1 ,williamson #ahgd4 ,asterochlaena 7,clepsydropsis7 duplex1 ,stenzel #ahhi4 ,clepsydropsis1 ,renault #ahif4 ,the vascular axis of the main axis of the frond is characterised by the hour-glass shape of the xylem which consists entirely of tracheae1 most of which are reticulately pitted4 ,in a transverse section 7fig4 #caj1 ,a7 the two ends of the stele are dissimilar2 at one end of the long axis is a small bay of thin-walled tissue 7phloem7 enclosed by a narrow band of xylem1 and at the other the bay is open and has two protoxylem groups4 ,the latter represents the earliest stage in the production of secondary bundles3 at a later stage the bay is closed by the elongation of the edges1 the enclosed group of phloem is vertically extended1 and the protoxylem strands are more widely separated4 ,the curved band of xylem becomes detached as a curved arc and divides into two 7fig4 #caj1 ,a74 ,in a single section of this species one often sees several strands of xylem enclosed in a common cortex with the main vascular axis2 these are the xylem bundles of lateral pinnae4 ,metaclepsydropsis duplex shows the method of branching of the petiole vascular axis which has already been noticed in ,diplolabis and ,zygopteris4 ,in reference to this feature1 ,williamson wrote in #ahgb--8;,i know of no recent fern in which the secondary branches of the petiole are thus given off in pairs1 which pairs are distichously arranged on the primary axis1 and each of which secondary petioles sustains ternary ones arranged distichously40 ,by slightly altering the primary stele of this type of frond1 by narrowing of the constricted portion of the hour-glass and extending the lateral groups of xylem obliquely upwards1 the form of stele shown in fig4 #caj1 ,a1 would be converted into the ,diplolabis type 7fig4 #cjh1 ,c74 ,clepsydropsis4 ,unger#aadg instituted this genus as a subdivision of ,corda's family ,rhaciopterideae#aadh1 the name having reference to the hour-glass form of the vascular axis#aadi4 ,the type-species ,c4 antiqua 7fig4 #cjh1 ,a7 is spoken of as the commonest fossil plant in the ,devonian rocks of ,thuringia4 ,in some sections the xylem has the form seen in fig4 #cjh1 ,a1 in which an invagination of thin-walled tissue occurs at each end2 in other sections 7fig4 #cjh1 ,a7 the bays become islands in the xylem4 ,solms-,laubach speaks of ,unger's species as ,rachiopteris 7,clepsydropsis7 antiqua4 ,p4 ,bertrand#aaej1 who has recently described ,unger's plant1 while recognising that ,c4 antiqua and ,metaclepsydropsis duplex closely resemble one another1 draws attention to certain differences in the structure of the xylem which he regards as sufficient to justify a generic separation4 ,the leaf-traces of ,clepsydropsis are described by ,bertrand as almost circular closed rings of xylem instead of an arc as in ,metaclepsydropsis4 ,illustration3 ,,fig4 #caj4 ,a4 ,metaclepsydropsis duplex4 ,b1 ,c4 ,stauropteris oldhamia4 ,d4 ,ankyropteris scandens4 ,a1 from a section in ,dr ,kidston's ,collection 7,lower ,carboniferous72 ,b1 ,c1 from sections in the ,cambridge ,botany ,school2 ,d1 after ,stenzel4 ,ankyropteris4 ,stenzel adopted this name for a subdivision of ,corda's genus ,zygopteris1 applying it to a species described by ,renault as ,z4 ,brongniarti1 to a ,permian species described by himself as ,z4 7,ankyropteris7 scandens1 and to ,z4 ,lacattii ,ren42 ,rachiopteris ,grayi ,will4 and ,rachiopteris corrugata ,will4 are also included in this genus4 ,the characters emphasised by ,stenzel#aaea are 7i7 the double anchor-like form of the ,h-shaped petiole strand in which the lateral arms 7antennae7 are curved like the flukes of an anchor1 and 7ii7 the emission of four rows of branches instead of two4 ,the latter distinguishing feature no longer holds good1 as ,z4 primaria also gives off four rows of bundles and not two as ,stenzel supposed4 ,p4 ,bertrand has adopted ,stenzel's genus in a narrower sense#aaeb4 ,illustration3 ,,fig4 #caa4 ,ankyropteris ,grayi4 ,stele4 7,from a section in ,dr ,kidston's ,collection1 #ah47 ,ankyropteris scandens ,stenzel#aaec4 ,fig4 #caj1 ,d4 ,this ,lower ,permian species is very similar to or perhaps identical with ,ankyropteris ,grayi 7,williamson74 ,the stem of ,a4 scandens was found in association with the roots of a ,psaronius stem evidently petrified in situ as it burrowed1 like ,tmesipteris1 tropical aroids1 and other recent plants1 among the living roots of the tree-fern4 ,the stem1 #aj-aa mm4 in diameter1 bore fronds with an ,h-shaped vascular strand1 small scale-leaves1 and adventitious roots4 ,the stele consists of a five-angled cylinder of scalariform tracheae surrounding an axial strand of parenchyma containing scattered tracheae of smaller diameter4 ,this axial tissue extends as a narrow strip into each of the short and obtusely truncated arms 7cf4 fig4 #caa74 ,a striking feature is the production of a shoot in the axil of the foliage-leaves 7fig4 #caj1 ,d71 a manner of branching characteristic of ,trichomanes 7see page #cfe74 ,ankyropteris ,grayi 7,will474 ,fig4 #caa4 ,in describing this species1 ,williamson wrote--8,that no classification of these fossil ferns based solely upon transverse sections of the petiolar bundles is or can be of much value1 is clearly shown when tested amongst those living ferns the classification of which is chiefly based upon the sporangial reproductive organs#aaed40 ,this is a view entirely opposed to that which inspires ,p4 ,bertrand's recent monograph4 ,whether the value attached to the vascular structure of petioles as a basis of classification is upheld or not1 it is noteworthy that since ,williamson expressed his opinion1 our knowledge of the anatomy of ferns and of the value of anatomical evidence has enormously increased4 ,the slender stem#aaee of this ,lower ,coal-,measures species agrees closely with that of ,a4 scandens2 it bore spirally disposed fronds1 scale-leaves1 and roots4 ,the stele has the form of an irregular five-rayed star 7fig4 #caa7 in which the relative length of the arms varies in different sections owing to the separation of the distal ends to form leaf-traces4 ,the axial region is composed of parenchyma and associated narrow tracheae1 as in ,a4 scandens4 ,the xylem1 with protoxylem elements at the ends and especially at the angles of the arms1 is completely surrounded by phloem4 ,the cortex consists internally of parenchyma which becomes thicker-walled towards the periphery and bears multicellular epidermal hairs4 ,a leaf-trace is detached in the form of a triangular strand and is formed by the tangential extension of the distal end of an arm of the stele4 ,the trace1 on its way through the cortex1 divides into two2 the outer branch gradually changes from a slightly curved band to an ,h-shaped meristele2 the inner branch1 which supplied an axillary shoot1 is similar to the stele of the stem1 but smaller4 ,scott#aaef has recently recorded the occurrence of scale-leaves 7aphlebiae7 in this species like those described by ,stenzel in ,a4 scandens4 ,illustration3 ,,fig4 #cab4 ,a4 ,thamnopteris ,schlechtendalii4 ,leaf-trace3 px1 protoxylem2 s1 island of parenchyma4 7,after ,kidston and ,gwynne-,vaughan47 ,b4 ,ankyropteris corrugata4 ,single trachea with tyloses4 ,c4 ,a4 bibractensis4 ,part of foliar strand4 7,after ,p4 ,bertrand47 ,bertrand includes in ,ankyropteris ,renault's species ,zygopteris bibractensis#aaeg and ,williamson's species ,rachiopteris corrugata#aaeh3 the former he names ,a4 bibractensis var4 westphaliensis4 ,the fossil described by ,williamson as ,r4 irregularis or inaequalis#aaei are the secondary branches of ,a4 bibractensis4 ,ankyropteris bibractensis1 var4 westphaliensis4 ,figs4 #cab1 ,c2 #cac4 ,the rachis stele of this species1 which is represented by portions of fronds only1 has the form of a double anchor 7fig4 #cac72 the antennae are continued at the outer edge of their distal ends into a narrow band 78filament0 of ,p4 ,bertrand7 7fig4 #cab1 ,c1 and #cac1 a7 composed of smaller tracheae and separated from the xylem of the antennae by a strip of thin-walled tissue 7phloem874 ,a group of protoxylem occurs at the junction of the filament and antennae4 ,the whole of the xylem is surrounded by phloem4 ,illustration3 ,,fig4 #cac4 ,ankyropteris bibractensis3 s1 stigmarian rootlet2 a1 narrow loop of xylem4 7,cambridge ,botany ,school2 #f74 ,the section reproduced in fig4 #cac shows the characteristic form of the petiolar vascular axis1 consisting of a horizontal band of metaxylem with groups of much smaller tracheae on both the upper and lower margins4 ,at the junction between the antennae1 curved like the flukes of an anchor1 and the horizontal band of xylem1 the latter is only one trachea in breadth4 ,the narrow loops of smaller xylem elements are shown on the outer edge1 a 7fig4 #cac71 of the antennae separated from the arcs of larger tracheae by a dark line which represents a crushed band of delicate tissue4 ,the spaces enclosed by the incurved antennae are largely occupied by parenchymatous ground-tissue4 ,the cylinder of outer cortex consists internally of comparatively thin-walled parenchyma succeeded externally by a zone of dark and thicker-walled cells characterised by a fairly regular arrangement in radial series1 as if formed by a secondary meristem2 there is1 however1 no indication of a meristematic layer4 ,below the small-celled epidermis are a few layers of thinner-walled cells which are not arranged in radial series4 ,the structure of the outer part of the cortex is similar to that in the petiole of recent species of ,angiopteris 7fig4 #bdc1 p4 #cai7 and ,marattia1 in which a more delicate hypoderm is succeeded by a band of mechanical tissue4 ,the rachis of this type of frond gives off two rows of lateral branches from the vascular axis1 the plane of symmetry being at right angles to the primary rachis4 ,each pinna bore at its base two aphlebiae supplied with vascular strands from the leaf-traces4 ,we have no certain information in regard to the sporangia of this species1 but ,scott points out that 8pear-shaped sporangia1 with a very broad and extensive annulus1 are commonly found associated with ,zygopteris bibractensis and ,z4 corrugata in the petrifactions of the ,english ,lower ,coal-,measures#aafj40 ,ankyropteris corrugata 7,will474 ,figs4 #cab1 ,b2 #cad-cag4 ,the stem of this type of ,zygoptereae was described by ,williamson from the ,lower ,coal-,measures of ,lancashire as ,rachiopteris corrugata and included by him in the sub-group ,anachoropteroides4 ,the stele 7fig4 #cad1 ,b7 is oval in transverse section2 it consists of a cylinder of xylem tracheae enclosing a central region occupied by parenchymatous tissue and scattered narrow scalariform tracheae4 ,the central tissue extends radially in the form of narrow arms which reach almost to the outer edge of the tracheal tissue and divide it up into #e-g groups4 ,a cylinder of thin-walled tissue encloses the xylem and in this occur groups of large sieve-tubes 7fig4 #cad1 ,d1 ,sv74 ,in a section of this species in the ,williamson ,collection#aafa the long axis of the stele has a length of #e mm4 and the diameter of the stem as a whole is #be cm4 ,the greater part of the extra-stelar tissue consists of large parenchymatous cells passing near the periphery into a band of darker and thicker-walled tissue4 ,reniform vascular strands traverse the cortex in an obliquely ascending course on their way to the leaves1 also smaller bundles1 some of which are given off directly from the stele1 while others are branches of the petiole vascular strands4 ,the petioles described by ,williamson as ,rachiopteris insignis#aafb were afterwards recognised by him as those of ,ankyropteris corrugata1 though this conclusion was not published#aafc4 ,williamson's species ,r4 insignis must not be confused with ,unger's ,culm species ,arctopodium insigne1 which ,solms-,laubach#aafd refers to as ,rachiopteris insignis4 ,the leaf-bundle of ,ankyropteris corrugata is at first reniform in contour 7fig4 #cad1 ,c1 ,p71 but as it becomes free from the stem it gradually assumes the ,h-shaped form 7figs4 #cae-cag74 ,this petiolar strand differs from that of ,ankyropteris bibractensis 7fig4 #cac7 in the shorter and less strongly curved antennae2 and1 as ,williamson first noticed1 the tracheae are frequently filled with thin-walled parenchyma 7fig4 #cab1 ,b74 ,the existence of scale-leaves or aphlebiae like those of ,ankyropteris scandens and ,a4 ,grayi has been recorded by ,scott in ,a4 corrugata#aafe4 ,the section represented in fig4 #cad1 ,c1 shows the relatively small size of the stele ,s in the stem of ,ankyropteris corrugata4 ,the main mass of the cortex consists of uniform parenchyma passing near the surface into darker and stronger tissue3 two vascular bundles are shown in the cortex1 one of which forms the conducting strand of a petiole1 ,p1 which has nearly freed itself from the stem3 the other bundle1 as shown by the examination of a series of sections1 eventually passes into another leaf-stalk4 ,a root of another plant has invaded the cortex at ,r1 fig4 #cad1 ,c4 ,illustration3 ,,fig4 #cad4 ,ankyropteris corrugata4 ,r1 intruded root2 ,p1 petiole2 ,s1 stele1 ,sv sieve-tubes4 ,a1 ,b4 ,from a section in the ,university ,college ,collection4 ,c4 ,after ,williamson4 ,d4 ,from a section in the ,williamson ,collection 7,british ,museum74 ,the form and structure of the stele is diagrammatically represented in fig4 #cad1 ,b4 ,the outer portion 7black7 consists of a cylinder of scalariform tracheae in which the position of groups of smaller elements 7protoxylem7 is shown by the white patches4 ,the xylem is thus seen to be mesarch4 ,the prominent group of xylem on the lower right-hand side of the section consists of tracheae1 cut across in an oblique direction1 which are about to pass out as a separate strand4 ,the centre of the stele is occupied by parenchymatous tissue in which are included scattered tracheae1 either singly or in small groups4 ,these medullary tracheae are rather narrower than those of the main xylem cylinder4 ,a characteristic feature is the radial outward extension into the xylem of the medullary parenchyma1 which tends partially to divide the tracheal cylinder into broad groups4 ,illustration3 ,,fig4 #cae4 ,ankyropteris corrugata 7,will474 ,petiolar vascular strand4 ,from a section in the ,university ,college 7,london7 ,collection2 after ,tansley #ce4 ,fig4 #cad1 ,a1 enlarged from fig4 ,b1 a1 shows the mesarch position of a protoxylem group1 and a few of the parenchymatous cells of one of the narrow arms of the axial tissue4 ,at ,sv in fig4 ,d a group of large sieve-tubes is seen separated from the xylem by a few parenchymatous cells1 and beyond the sieve-tubes are some tangentially elongated cells4 ,both the sieve-tubes1 ,sv1 and the flattened cells resemble tissues in a corresponding position in the steles of modern ,osmundaceae4 ,in a section of ,ankyropteris corrugata in the ,williamson ,collection the radial arrangement of the more external metaxylem elements suggests the addition of secondary tracheae#aaff4 ,this suggestion of secondary thickening1 a point which requires much more thorough investigation1 is interesting in relation to a new type of stem named by ,scott ,botrychioxylon#aafg1 but not yet fully described4 ,this generic name has been given to a stem stele which closely resembles that of ,ankyropteris corrugata except in the regular radial arrangement of the peripheral xylem elements4 ,the name ,botrychioxylon was chosen by ,scott because of the secondary xylem characteristic of the recent genus ,botrychium 7fig4 #bdg1 p4 #cbb74 ,illustration3 ,,fig4 #caf4 ,ankyropteris corrugata4 ,petiole4 a1 narrow xylem loop2 b1 spaces in cortex4 ,from a section in the ,cambridge ,botany ,school ,collection4 7 #aj47 ,in the petiolar vascular strand represented in fig4 #cae the narrow band of tracheae which forms a loop external to the antennae is clearly seen1 also the small-celled parenchyma between the loops and the larger metaxylem elements of the antennae4 ,the crushed tissue lying on the outer face of each of the loops probably represents the phloem and pericycle2 the thin-walled elements above and below the horizontal band of metaxylem are probably sieve-tubes4 ,fig4 #caf shows a transverse section of a petiole of this species3 the loops1 a1 of small tracheae are seen bending round the outer edge of the antennae4 ,the inner and more delicate cortical tissue is partially preserved and spaces1 b1 have been formed in it as the result of contraction previous to petrifaction4 ,in the petiole represented in fig4 #cag the tracheae of the horizontal band are considerably crushed2 the section is1 however1 of interest because of the presence of ,lyginodendron roots1 l1 in the space originally occupied by the inner cortex4 ,illustration3 ,,fig4 #cag4 ,ankyropteris corrugata4 ,from a section in the ,cambridge ,botany ,school ,collection4 7 #i47 ,in a paper on the tyloses of ,rachiopteris corrugata1 ,weiss#aafh draws attention to the fact that similar inclusions have not been found in the tracheae of recent ferns4 ,the occurrence of thin-walled parenchymatous cells in the large tracheae of ,ankyropteris corrugata petioles and of other species is a striking feature4 ,williamson#aafi compared these cells with the tyloses in the vessels of recent flowering plants1 and in a later paper#aagj he suggested that the included cells may belong to saprophytic or parasitic fungi4 ,it is1 as ,weiss points out1 difficult to explain the occurrence of tyloses in tracheae not immediately in contact with living parenchyma4 ,it may be that the pits in the tracheae of ,ankyropteris were open spaces as in the xylem of recent ferns described by ,gwynne-,vaughan1 and if so this would facilitate the invasion of the conducting elements by growing cells4 ,a comparison is made by ,weiss between certain cell-groups found by him in the tracheae of ,ankyropteris and by ,miss ,jordan#aaga in the vessels of the recent dicotyledon ,cucumis sativus4 ,in a more recent paper on tyloses ,miss ,mc,nicol#aagb expresses the opinion that pseudoparenchyma in the tracheae of the fossil petioles owes its origin to fungal hyphae4 ,williamson compared the petiole bundles of ,ankyropteris corrugata with those of recent ,osmundaceae1 a comparison based on the structure of the leaf-trace before its separation from the stem and its assumption of the ,h-form4 ,it is noteworthy1 however1 that this comparison has acquired a greater significance as the result of recent work4 ,the stele of ,ankyropteris bears a fairly close resemblance to that of ,zalesskya described by ,kidston and ,gwynne-,vaughan2 in both types the xylem is represented by two kinds of tracheal tissue4 ,in the ,permian ,osmundaceous genus the centre of the stele consists of short storage tracheids1 while in ,ankyropteris we may regard the central parenchyma and scattered tracheae as derivatives of the solid xylem core of some ancestral type4 ,moreover1 the appearance and arrangement of the phloem and the tangentially elongated elements external to it 7fig4 #cad7 remind one of the extra-xylem zone in recent ,osmundaceae4 ,that the ,osmundaceae and ,zygoptereae are closely related groups there can be little doubt2 of this affinity and common origin#aagc ,ankyropteris corrugata affords striking evidence4 ,the difference between the steles of ,ankyropteris ,grayi and ,a4 scandens 7figs4 #caj1 ,d2 #caa7 and that of ,ankyropteris corrugata is comparatively small4 ,in the two former species the cylindrical form has become stellate owing to the radial extension of the xylem arms4 ,it may be that this more elaborate style of vascular construction is connected with the climbing habit of ,a4 scandens and possibly ,a4 ,grayi4 ,the radial extension of the xylem and the consequent alternation of the yielding parenchymatous cortex and the more rigid tracheal arms would probably render the water-conducting elements less liable to injury in a twisting axis#aagd4 ,in ,anachoropteris ,decaisnii#aage1 described by ,renault1 and more especially in ,asterochlaena laxa#aagf ,stenzel1 a ,lower ,permian type from ,saxony 7fig4 #cbd71 the xylem of the stele is much more deeply lobed than in ,ankyropteris ,grayi or ,a4 scandens4 ,illustration3 ,,fig4 #cah4 ,etapteris ,scotti1 ,p4 ,bert4 7,from ,tansley1 after ,renault47 ,etapteris ,scotti4 ,figs4 #cjh1 ,b2 #cji1 ,e2 #cah4 ,p4 ,bertrand has proposed this name for a species of petiole from the ,lower ,coal-,measures of ,england referred by ,binney#aagg to ,zygopteris ,lacattii ,ren41 and included by ,williamson#aagh in his comprehensive genus ,rachiopteris4 ,bertrand#aagi regards the ,english species1 which is recorded also from ,germany#aahj1 as distinct from ,renault's type#aaha and therefore proposes a new name4 ,the petiole stele has the ,h-form1 but its structure is simpler than that of the ,ankyropteris petiole4 ,the horizontal band of xylem has at each end two oval groups of tracheae connected with it by a single row of xylem elements 7fig4 #cah74 ,from the lower part of each oval group a small strand is detached2 the two strands from one side of the stele coalesce and then separate to pass into two pinnae4 ,fig4 #cjh1 ,b1 shows four stages in the giving-off of the secondary branches4 ,this species1 therefore1 produces four rows of branches in alternate pairs from the right and left sides of the petiole4 ,the first stage is shown at #j1 #j1 fig4 #cjh1 ,b2 the two projecting groups of protoxylem mark the points of departure of a pair of small strands4 ,at #a1 the projections are more prominent1 and at #b a pair of strands has become detached3 at a later stage1 #c1 these two strands unite to divide later 7#d7 into two slightly curved bundles4 ,illustration3 ,,fig4 #cai4 ,a-,c4 ,sporangia of ,etapteris 7874 ,d-,g4 ,botryopteris forensis4 7,after ,renault47 ,our knowledge of the fructification of ,etapteris is based on ,renault's account of sporangia1 which he regarded as belonging to ,zygopteris 7,etapteris7 ,lacattii4 ,they have the form of elongated slightly curved sacs 7#be #ac mm47 borne in clusters 7fig4 #cai1 ,a-,c7 on slender ramifications of the fertile frond1 which is characterised by the absence of a lamina4 ,each sporangium has a pedicel1 and three to eight sporangia are attached to a common peduncle2 the walls of the sporangia are at least two cell-layers in thickness and the annulus consists of a band of thick-walled cells passing from the crest down each side 7figs4 ,b and ,c71 thus differing from the sporangia of ,botryopteris 7fig4 #cai1 ,d1 ,f7 in which the broad annulus is confined to one side4 ,illustration3 ,,fig4 #cbj4 ,stauropteris oldhamia4 7,after ,tansley4 ,from a section in ,dr ,scott's ,collection4 #fj47 ,it is practically certain that the fronds described by ,grand',eury#aahb as ,schizopteris pinnata 7fig4 #cji1 ,e7 and ,schizostachys frondosus represent respectively the sterile and fertile leaves of ,etapteris4 ,zeiller#aahc gives expression to this by substituting the generic name ,zygopteris for ,schizopteris1 and we may now speak of the leaves as ,etapteris4 ,dr ,white#aahd has referred to a new genus1 ,brittsia1 some impressions of pinnate fronds from the ,coal-,measures of ,missouri which1 as he points out1 bear a close resemblance to ,schizopteris pinnata ,grand',eury 7fig4 #cji1 ,e74 ,no sporangia have been found2 it is1 however1 probable that ,brittsia problematica represents fragments of a leaf borne by a plant closely allied to ,etapteris 7,zygopteris74 ,the broad rachis bears crowded pinnae given off at a wide angle2 the small pinnules are rather deeply lobed or pinnatifid 7#c-aj mm4 long by #ae-c mm4 broad74 ,the lamina is traversed by irregularly lobed and occasionally anastomosing veins4 ,in the fertile pinnae the segments have no lamina but bear bundles of pedicellate sporangia4 ,it should be noticed that the sporangia described by ,renault and by other authors as those of ,zygopteris 7fig4 #cai1 ,a-,c7 have not been found in organic continuity with a frond showing a well-preserved vascular strand4 ,it is1 however1 certain that this characteristic annulate sporangium1 borne on branched and slender pedicels1 was produced on fronds with a much reduced lamina belonging to some species of the ,zygoptereae1 ,etapteris and probably also ,ankyropteris4 ,stauropteris4 ,this genus was instituted by ,binney for petioles from the ,lower ,coal-,measures of ,oldham 7,lancashire74 ,stauropteris oldhamia ,binney#aahe is characterised by a stele 7figs4 #cjh1 ,e-,g2 #caj1 ,c2 #cbj2 #cba7 composed of four groups of xylem which ,bertrand regards as homologous with the antennae of ,diplolabis1 ,ankyropteris1 and ,etapteris1 the horizontal cross-piece of these genera being absent in ,stauropteris4 ,williamson spoke of this species as 8one of the most beautiful and also one of the most perplexing of the plants of the ,coal-,measures02 he discussed its possible affinity with both ,lycopods and ferns1 deciding in favour of the latter group#aahf4 ,in transverse section the petiolar vascular axis is approximately square1 the xylem groups forming the ends of the diagonals2 the tracheal groups are separated by phloem and the centre of the stele in the primary rachis is also occupied by that tissue1 which is connected by four narrow strips with the external phloem4 ,the structure of the petiolar vascular axis is very clearly shown in the drawing by ,mrs ,tansley reproduced in fig4 #cbj4 ,protoxylem elements occur close to the surface of each of the four arms of the xylem2 the bays between the two lateral and the two lower xylem groups contain large sieve-tubes4 ,portions of the inner cortex are seen in places abutting on the small-celled pericyclic tissue4 ,the right and left halves of the stele are not absolutely identical 7fig4 #cbj2 fig4 #cjh1 ,e72 this is due to the fact that secondary branches are given off in four rows1 two alternately from the right and left sides4 ,the preparation for the departure of the lateral strands alters the configuration of the stelar xylem groups4 ,the protoxylem groups are not external but separated from the surface by one or two layers of metaxylem4 ,in fig4 #cjh1 ,e1 the occurrence of two protoxylem strands in the right-hand groups of metaxylem marks an early stage in the detachment of branches4 ,these two protoxylems are the result of division of single protoxylem strands like those in the left-hand half of the stele4 ,at a later stage the petiolar stele assumes the form shown in fig4 #cjh1 ,f1 and two small bundles are detached to supply aphlebiae3 this is followed by the stage shown in fig4 ,g1 where two four-armed strands are passing out to a pair of branches of the leaf axis4 ,the separation of these two meristeles leaves the right-hand half of the stele in the condition seen on the left-hand side of fig4 ,e4 ,the diagrammatic sketch represented in fig4 #caj1 ,c1 shows one pair of branches in organic connexion with the rachis1 and each of these arms contains an obliquely cut vascular strand like those in fig4 #cjh1 ,g4 ,the cortex consists for the most part of fairly thick-walled parenchyma 7fig4 #cba7 which in the hypodermal region is replaced by a zone of thin-walled lacunar tissue4 ,a few stomata have been recognised in the epidermis#aahg4 ,the lower left-hand branch seen in fig4 #caj1 ,c1 has been shaved by the cutting wheel so that the aerenchymatous tissue1 l1 is shown in surface-view3 a portion of this tissue is enlarged in fig4 ,c4 ,the same delicate chlorophyllous tissue forms a folded and shrivelled layer with an uneven margin on the surface of the rachis and lateral branches4 ,this hypha-like tissue1 which was discovered by ,scott#aahh and figured by ,bertrand#aahi1 doubtless represents the much reduced lamina of the highly compound leaves2 it may be compared with the green outer cortex of ,psilotum shoots and with the lacunar tissue in the capsule of the common moss1 ,funaria hygrometrica4 ,illustration3 ,,fig4 #cba4 ,stauropteris oldhamia3 a1 sections of pinnae4 7 #aj4 ,from a section in the ,cambridge ,botany ,school ,coll47 ,the rachis reproduced in fig4 #cba is surrounded by an enormous number of sections1 some transverse1 others more or less vertical1 of branchlets of various sizes4 ,fig4 #caj1 ,b1 shows the three-rayed vascular axis of a branch of a lower order than those seen in fig4 ,c1 and the single vascular strands of still finer ramifications of the leaf4 ,the extraordinary abundance of axes of different sizes1 many of which are cut in the plane of branching1 in close association with the rachises of ,stauropteris affords a striking demonstration of the extent to which the subdivision of the frond was carried in a small space4 ,the leaves must have presented the appearance of a feathery plexus of delicate green branchlets devoid of a lamina1 some of which bore terminal sporangia4 ,it may be that the delicate fronds were borne on a slender rhizome which lived epiphytically in a moist atmosphere on the stouter stems of a supporting plant4 ,the sporangia#aaij of ,stauropteris oldhamia are exannulate and nearly spherical1 with a wall of more than a single row of cells2 they occur at the tips of slender and doubtless pendulous branchlets4 ,the discovery by ,scott#aaia of germinating spores 7fig4 #cbc7 in a sporangium of this type supplies an interesting piece of evidence in favour of the fern nature of these reproductive organs4 ,similar germinating spores have been described by ,boodle#aaib in sporangia of ,todea4 ,illustration3 ,,fig4 #cbb4 ,sporangia of ,stauropteris oldhamia4 ,st1 stomium3 p1 palisade tissue4 7,from ,tansley1 after ,d4 ,h4 ,scott1 from a drawing by ,mrs ,d4 ,h4 ,scott47 ,stauropteris burntislandica4 ,this ,lower ,carboniferous plant identified by ,williamson with the ,oldham plant from the ,lower ,coal-,measures is referred by ,bertrand to a distinct species4 ,in the structure of the rachis stele it agrees closely with ,stauropteris oldhamia2 the main vascular strand gives off four rows of branches1 two from each side1 and aphlebiae were present at the common base of each pair of pinnae4 ,mrs ,scott#aaic1 who has recently described the sporangia of this species1 speaks of one specimen in which germinating spores were found4 ,the same author gives an account of some curious spindle-shaped bodies which she found in association with ,s4 burntislandica4 ,the nature of these organs is uncertain2 ,mrs ,scott inclines to regard them as glands borne in pairs on lateral pedicels of the frond3 she adopts for these the name ,bensonites fusiformis proposed by ,dr ,scott4 ,if there is a reasonable probability1 as there certainly seems to be1 in favour of connecting these organs with ,stauropteris1 it is legitimate to question the desirability of adding to the long list of names included in the group ,coenopterideae4 ,illustration3 ,,fig4 #cbc4 ,germinating spores from a sporangium of ,stauropteris4 7,from ,tansley1 after ,d4 ,h4 ,scott47 ,corynepteris4 ,fig4 #cji1 ,c1 ,d4 ,this genus was founded by ,baily#aaid on fragments of a fern from ,carboniferous rocks in ,county ,limerick1 ,ireland1 characterised by a peculiar type of fructification which he named ,corynepteris stellata4 ,more complete examples of the same genus have been described by ,zeiller#aaie from the ,coal-field of ,valenciennes4 ,the sporangia are large1 ovoid1 and sessile2 the annulus 7fig4 #cji1 ,d7 has the form of a complete vertical band several cells in breadth3 five to ten sporangia are grouped round a receptacle4 ,zeiller describes two species as ,sphenopteris 7,corynepteris7 coralloides ,gutb4 and ,s4 7,corynepteris7 ,essinghii ,and42 in both the fronds are quadripinnate and bear aphlebiae at the base of the pinnae4 ,the former species is recorded by ,kidston#aaif from the ,south ,wales ,coal-field4 ,a single pinnule of ,c4 coralloides is shown in fig4 #cji1 ,c4 ,potoni#aaig refers this frond to his genus ,alloiopteris3 the portion of a pinna represented in fig4 #ced1 ,g shows the characteristic modified pinnule next the rachis4 ,zeiller draws attention to the occurrence of two parallel lines on the rachis of a specimen of ,corynepteris coralloides which he figures#aaih1 and suggests that these may indicate the existence of an ,h-shaped form of vascular strand like that of ,etapteris and ,ankyropteris4 ,the sorus of ,corynepteris is comparable with that of the ,marattiaceae1 but the broad annulus is a difference which suggests affinity to ,etapteris4 ,the sorus is similar to that in ,diplolabis 7fig4 #cji1 ,a71 but in that genus the sporangia are exannulate4 ,the vascular axis in the stems of different members of the ,coenopterideae assumes a variety of types4 ,in ,botryopteris antiqua the xylem forms a solid protostele in which no protoxylem strands have been recognised2 in other species1 e4g4 ,b4 ramosa1 the cylindrical stele is similar to that of ,trichomanes radicans 7,hymenophyllaceae7 in the more or less central position of the protoxylem4 ,in ,botryopteris forensis the protostele is said to be exarch4 ,the probability is that the central ,botryopteris type is the endarch protostele1 a form of vascular axis which may be regarded as primitive4 ,the leaf-traces of the ,lower ,carboniferous ,botryopteris antiqua are simple oval strands differing but slightly from the cylindrical stele of the stem4 ,in the ,upper ,carboniferous ,british species the petiolar vascular strand has become more specialised and farther removed from that of the stem2 in ,b4 forensis the distinction between leaf and stem steles is still more pronounced4 ,it is perhaps legitimate to regard these types as representing an ascending series1 the more primitive of which are distinguished by the greater similarity between leaf and stem1 organs differentiated from a primitive thallus#aaii1 that is from a vegetative body4 ,portions of this ultimately became specialised as lateral members or leaves1 while a portion acquired the character of a radially constructed supporting axis or stem4 ,sidenote3 ,,ankyropteris1 ,,etc4 ,the vascular strand characteristic of the ,zygoptereae is represented by the ,h-shaped form as seen in ,ankyropteris corrugata or in a more complex form in ,a4 bibractensis4 ,this style of strand may be regarded as a development from the simple strands of ,grammatopteris and ,tubicaulis or ,botryopteris antiqua along other lines than those followed by ,b4 forensis4 ,the extension of the xylem in two symmetrically placed arms at the ends of the cross-piece of the ,h is correlated with the habit of branching of the leaf-system which forms one of the striking peculiarities of many of the ,zygoptereae4 ,the solid type of stele characteristic of the ,botryoptereae is closely matched by that in the ,lower ,carboniferous stem discovered by ,mr ,gordon#abjj4 ,by the partial transformation of the central xylem region into parenchymatous tissue and the concentration of water-conducting elements in the peripheral region the style of ,ankyropteris corrugata was developed4 ,the vascular strand of the older plant1 which is of the ,diplolabis type1 may be regarded as a more primitive style than that of the ,h-form of petiole strand represented by ,ankyropteris corrugata4 ,a further stage in evolution is seen in the stem stele of ,ankyropteris ,grayi and ,a4 scandens1 both of which have the ,h-form of meristele4 ,this step in increasing complexity of stem stele1 though probably connected with the increasing specialisation of the leaf-traces1 as held by ,mr ,tansley1 may also be associated with the development of a climbing habit4 ,in ,asterochlaena laxa ,stenzel 7fig4 #cbd7 and ,a4 ramosa 7,cotta7#abja the tendency towards a stellate expansion of the originally cylindrical form of stele reaches a higher degree1 with the result that a style is evolved which agrees closely with that of the conducting tissue of some existing ,dicotyledonous ,lianes4 ,attention has already been drawn to the generalised features exhibited by the ,coenopterideae both in the anatomy of the steles and in the structure of the sporangia4 ,the conclusion arrived at is that while the ,coenopterideae foreshadow in some of their characters more than one group of more recent ferns1 some at least of their members afford convincing evidence of the correctness of the view--which is also that of ,dr ,kidston and ,mr ,gwynne-,vaughan--that the ,osmundaceae and the ,coenopterideae are offshoots of a common stock4 ,illustration3 ,,fig4 #cbd4 ,asterochlaena laxa3 part of stem with petiole and a few roots4 ,from ,tansley1 after ,stenzel4 ,,chapter ,,xxvi4 ,,hydropterideae ,marsiliaceae4 ,salviniaceae4 ,the unsatisfactory and meagre records in regard to the past history of these heterosporous ,filicales render superfluous more than a brief reference to the recent species4 ,marsiliaceae4 ,this family is usually spoken of as including the two genera ,marsilia and ,pilularia4 ,lindman#abjb has however founded a third genus1 ,regnellidium1 on a ,brazilian plant which is distinguished by some well-defined characters from all species of ,marsilia4 ,the members of the ,marsiliaceae live for the most part in swampy situations4 ,marsilia is represented in ,europe by ,m4 quadrifoliata ,l4 which occurs in ,portugal1 ,france1 ,germany and other parts of the ,continent1 extending also to ,kashmir1 ,northern ,china1 and ,japan4 ,of the other #ec species1 #ag are recorded from different regions in ,africa1 while others occur in ,south ,america1 ,asia#abjc1 ,australia1 and elsewhere4 ,pilularia globulifera ,l4 is the only ,british representative of the ,hydropterideae4 ,the remaining four species of the genus occur in ,south ,america1 ,california1 ,new ,zealand1 ,australia1 and ,p4 minuta ,dur4 is met with in the ,south of ,france1 ,algeria1 and ,asia ,minor in subtropical or warm temperate regions4 ,the ,marsiliaceae are regarded as more nearly related to the ,schizaeaceae than to any other family of homosporous ferns#abjd4 ,their heterospory1 the production of sporangia in closed fruit-like sporocarps1 and the anatomical features associated with existence in marshy habitats1 tend to obscure the resemblances to the true ferns4 ,the genus ,marsilidium proposed by ,schenk#abje for a piece of an axis1 bearing apparently a whorl of six leaflets1 from the ,wealden of ,osterwald1 cannot be regarded as satisfactory evidence of the existence of the ,marsiliaceae in the ,wealden flora of ,north ,germany4 ,the six leaflets of ,marsilidium speciosum1 having a length of #e cm41 are similar in shape to the four leaflets of recent species of ,marsilia1 but they differ in the repeated dichotomy of the veins from the reticulate venation of the recent forms4 ,it is worthy of note1 however1 that in ,lindman's ,brazilian type ,regnellidium diphyllum 7fig4 #cbf1 ,a71 the leaflets are characterised by dichotomous and not by anastomosing veins4 ,hollick#abjf has described some impressions of imperfect orbicular leaves with a 8finely flabellate obscurely reticulated787 venation0 from ,cretaceous rocks of ,long ,island as ,marsilia ,andersoni1 but these are too fragmentary to be accorded this generic designation4 ,my friend ,dr ,krasser informs me that he is describing some well-preserved leaves from ,cretaceous beds of ,grnbach in ,lower ,austria as ,marsilia ,nathorsti#abjg4 ,he compares these with the recent form ,marsilia elata1 a variety of ,m4 ,drummondi4 ,another ,lower ,cretaceous species ,marsilia perucensis has been figured by ,fri and ,bayer#abjh as a stalked fruit-like body from ,bohemia4 ,this was originally described by ,velenovsk as ,m4 cretacea1 but under this name ,heer#abji had previously recorded a supposed sporocarp from ,greenland4 ,these fossils have little claim to recognition as examples of ,marsiliaceous plants4 ,the fragment figured by ,heer#abaj from ,tertiary rocks of ,oeningen as ,pilularia pedunculata is too small to determine with reasonable accuracy4 ,other supposed representatives of the family mentioned in palaeobotanical literature are not of sufficient importance to describe4 ,salviniaceae4 ,the two genera of ,salviniaceae1 ,salvinia and ,azolla1 are water plants1 and are usually described as annuals which survive the less favourable season in the form of detached sporocarps4 ,goebel#abaa states that all the tropical species of ,salvinia known to him have an unlimited existence4 ,salvinia natans1 ,hoffm41 the only ,european species1 extends from the ,south of ,france to ,northern ,china and the plains of ,india3 the other twelve species are mostly tropical4 ,azolla1 represented by four species1 occurs in ,western and ,southern ,north ,america1 ,south ,america1 ,madagascar1 ,australia1 ,new ,zealand1 and is widely spread in tropical ,asia and ,africa4 ,species of ,azolla frequently form a considerable proportion of the floating carpet of vegetation on inland waters#abab growing under conditions which might be supposed favourable for preservation in a fossil state4 ,the ,salviniaceae1 though probably rather farther removed than the ,marsiliaceae from the homosporous ,filicineae1 are considered by ,bower#abac to be related to the ,gradatae1 but modified in consequence of their aquatic habit and the assumption of heterospory4 ,no undoubted examples of fossil species of ,azolla have been described4 ,salvinia1 on the other hand1 is represented by several ,tertiary species1 for the most part founded on leaves only1 and ,hollick#abad1 who published a list of fossil ,salvinias1 has described detached leaves as ,salvinia elliptica ,newb4 from what may be ,upper ,cretaceous rocks from ,carbonado1 ,washington4 ,some of the leaves figured as ,tertiary ,salvinias are of no value as evidence of the former distribution of the genus#abae4 ,from the ,coal-beds of ,yen-,bi 7,tonkin71 probably of ,miocene age1 ,zeiller#abaf has figured some well-preserved impressions of oval or orbicular leaves1 #ae mm4 long and #aj-bj mm4 broad1 characterised by reticulate venation and by cordate bases1 which he refers to ,heer's ,swiss species ,salvinia formosa#abag4 ,dr ,zeiller#abah in the most recently published part of his series of valuable rsums of palaeobotanical literature refers to a description by ,brabenec of specimens of this species from ,bohemian ,tertiary beds showing both microspores and megaspores4 ,one of the most complete specimens so far discovered has recently been described by ,fritel#abai from ,eocene beds of the ,paris ,basin as ,salvinia ,zeilleri4 ,this species1 founded on portions of stems bearing floating leaves1 submerged root-like leaves1 and sporocarps1 is compared with a recent tropical ,american species ,s4 auriculata4 ,it is noteworthy that no authentic records of ,hydropterideae have been discovered in ,palaeozoic rocks#abbj4 ,comparisons have been made in the case of the genera ,traquairia ,carr4 and ,sporocarpon ,will4 with the reproductive organs of ,azolla#abba1 but these rest on a wholly insufficient basis4 ,dawson#abbb proposed the generic name ,protosalvinia for some spores of ,devonian age1 which he regarded on inadequate grounds as evidence of ,palaeozoic ,hydropterideae4 ,zeiller#abbc1 in discussing the possible relationships of the problematical type ,chorionopteris gleichenioides ,cord41 suggests a possible alliance with the ,hydropterideae4 ,corda founded the genus ,chorionopteris#abbd on some small fragments of pinnules1 #f-g mm4 long1 found in the ,carboniferous rocks of ,radnitz in ,bohemia4 ,the lobes of the pinnules are incurved distally to form a capsule1 containing four sporangia1 which apparently opened on dehiscence into four valves2 the spores are of one size4 ,the material is however insufficient for accurate determination4 ,there is no evidence contributed by fossil records which indicates a high antiquity for the ,hydropterideae4 ,it is unsafe to base any conclusion on the absence of undoubted ,palaeozoic representatives of this group2 but the almost complete absence of records in pre-,tertiary strata is a fact which may be allowed some weight in regard to the possible evolution of the heterosporous filicales at a comparatively late period in the earth's history4 ,a description of the ,mesozoic genus ,sagenopteris may be conveniently included in this chapter1 though as in many other instances the inclusion of a genus under the heading of a recent family name does not by any means imply that the position of the extinct type is regarded as settled4 ,sagenopteris4 ,this generic name was applied by ,presl#abbe to small fronds composed of four or rarely two palmately disposed leaflets with a more or less distinct midrib and anastomosing secondary veins4 ,schimper#abbf compared ,sagenopteris with ,marsilia1 but did not regard the resemblance as evidence of relationship4 ,nathorst#abbg expressed the opinion that certain fruit-like bodies obtained from the ,rhaetic beds of ,scania are of the nature of sporocarps and were borne by ,sagenopteris1 with the leaves of which they were associated4 ,he published a drawing of part of a fruit showing on its partially flattened surface some raised oval bodies which are considered to be spores4 ,dr ,nathorst kindly placed at my disposal the drawings reproduced in fig4 #cbe made from some of his specimens found at ,bjuf in ,scania4 ,in contour and superficial features1 e4g4 the veining on the wall1 these bodies bear a fairly close resemblance to the sporocarps of recent species of ,marsilia4 ,they were found in association with the leaves of ,sagenopteris undulata ,nath41 an abundant ,scania type similar in form to the ,english ,jurassic species ,s4 ,phillipsi 7figs4 #cbg1 #cbh74 ,heer was independently led by an examination of some examples of the ,swedish 8fruits0 to compare them with the sporocarps of ,marsilia4 ,a small spherical body is figured by ,zigno#abbh close to a leaf of his species ,s4 angustifolia1 which may be a sporocarp4 ,in a recent paper1 ,salfeld#abbi says that he found fructification on the lower face of the leaflets of ,s4 ,nilssoniana ,brongn4 from ,german ,jurassic rocks1 but he brings forward no evidence in support of this statement4 ,the systematic position of ,sagenopteris is by no means settled4 ,in a previous account of the genus ,i expressed the view that it is probably a member of the true ferns#abcj1 but the resemblance of ,dr ,nathorst's drawings to the ,marsilian sporocarps influences me in favour of his opinion that ,sagenopteris may belong to the ,hydropterideae4 ,the evidence1 as ,solms-,laubach#abca states1 is not wholly satisfactory3 ,schenk points out that the frequent occurrence of detached ,sagenopteris leaflets suggests that they easily fell off the petiole1 whereas in ,marsilia the leaflets do not fall off independently4 ,the discovery of a new type of ,marsiliaceae in ,brazil1 which ,lindman has described as ,regnellidium diphyllum#abcb 7fig4 #cbf1 ,a71 affords an additional piece of evidence bearing on the comparison of ,sagenopteris with members of this family4 ,in ,regnellidium the leaves differ from those of ,marsilia in bearing two instead of four leaflets1 and in the former the veins are repeatedly forked1 and do not anastomose as in ,marsilia4 ,in the possession of only two leaflets ,regnellidium agrees with some forms of ,sagenopteris 7fig4 #cbh74 ,illustration3 ,,fig4 #cbe4 ,sporocarp-like bodies found in association with the leaves of ,sagenopteris4 7,nat4 size4 ,from drawings supplied by ,dr ,nathorst47 ,illustration3 ,,fig4 #cbf4 ,a4 ,regnellidium diphyllum ,lind4 ,single leaf and stalked sporocarp4 7 nat4 size4 ,after ,lindman47 ,b4 ,cuticle of ,sagenopteris rhoifolia4 7,after ,schenk47 ,sagenopteris ,phillipsi 7,brongniart7#abcc4 ,figs4 #cbg1 #cbh4 #ahbh4 ,glossopteris ,phillipsi1 ,brongniart1 ,hist4 vg4 foss4 p4 #bbe1 ,pls4 ,,lxi4 bis1 ,,lxiii4 #ahch4 ,sagenopteris ,phillipsi1 ,presl1 in ,sternberg's ,flor4 ,vorwelt1 vii4 p4 #fi4 ,illustration3 ,,fig4 #cbg4 ,sagenopteris ,phillipsi4 ,a4 ,from the type-specimens of ,lindley and ,hutton 7,glossopteris ,phillipsi74 ,gristhorpe ,bay1 ,yorkshire4 ,british ,museum1 ,no4 #cibba4 ,slightly reduced4 ,m4,s4 ,b4 ,from a specimen in the ,british ,museum 7#cibbb74 ,nat4 size4 ,figured by ,lindley and ,hutton as ,glossopteris ,phillipsi4 ,the fronds of this common ,jurassic species1 which is recorded from many ,european localities1 from ,north ,america1 ,australia1 the ,antarctic regions#abcd1 and elsewhere1 are very variable as regards the form1 size1 and number of the leaflets4 ,frond petiolate1 in some forms the petiole bears four linear or oval-lanceolate leaflets having a distinct midrib and oblique anastomosing veins4 ,in others a shorter winged petiole bears one or two shorter and broader1 somewhat obcuneate1 leaflets without a midrib4 ,it is probable that ,bunbury#abce was correct in his opinion that the specimen figured by ,lindley and ,hutton#abcf as ,otopteris cuneata1 characterised by two leaflets 7fig4 #cbh71 is not specifically distinct from the normal form with four leaflets 7fig4 #cbg74 ,similarly1 such specimens as that represented in ,pl4 ,,xviii41 fig4 #c of the first part of my ,jurassic ,flora1 in which a short stalk bears only one leaflet may1 provisionally at least1 be included in ,brongniart's species4 ,yabe#abcg describes a form with two leaflets from ,jurassic rocks of ,korea as ,sagenopteris bilobata which resembles ,s4 ,phillipsi2 and ,moeller#abch records a specimen similar to that represented in fig4 #cbh from ,bornholm as ,s4 cuneata 7,lind4 and ,hutt474 ,illustration3 ,,fig4 #cbh4 ,sagenopteris ,phillipsi4 ,from a specimen in the ,manchester ,university ,museum4 ,nat4 size4 ,the leaf shown in fig4 #cbg1 ,a1 in which the longest segments are #de cm4 in length1 represents the most abundant form and illustrates the very close agreement between ,s4 ,phillipsi and the ,rhaetic species ,s4 rhoifolia4 ,fig4 #cbg1 ,b1 which is drawn from a specimen figured by ,lindley and ,hutton#abci1 shows a leaf with longer 7#fe cm47 and much narrower segments4 ,broader leaflets are occasionally met with in which the lamina reaches a length of #aa cm4#abdj ,leaves with leaflets narrower 7#c mm4 broad7 than those represented in fig4 #cbg1 ,b1 are described by ,zigno#abda from ,jurassic beds of ,italy as ,s4 angustifolia and by ,moeller#abdb from the ,jurassic of ,bornholm as ,s4 ,phillipsi f4 pusilla4 ,a coarser type of venation than that of ,s4 ,phillipsi is occasionally found in ,jurassic examples1 as in ,s4 grandifolia ,font4#abdc from ,oregon and ,s4 ,nathorsti ,barth4 from ,bornholm#abdd4 ,sagenopteris is recorded also from several ,rhaetic floras4 ,the best known species1 ,s4 rhoifolia ,presl#abde1 is hardly distinguishable from some forms of ,s4 ,phillipsi or from the ,italian ,jurassic species described by ,zigno as ,s4 ,goeppertiana#abdf1 though the leaflets are usually rather larger4 ,this species was first described by ,brongniart as ,filicites ,nilssoniana#abdg1 and a few authors#abdh have adopted this specific name because of its priority over ,presl's designation4 ,as ,nathorst remarks1 to give up the well-known name ,s4 rhoifolia for ,s4 ,nilssoniana is 8mere pedantry40 ,the epidermis of ,s4 rhoifolia as figured by ,schenk#abdi consists of cells with straight and not undulating walls3 stomata occur on the lower surface 7fig4 #cbf1 ,b74 ,rhaetic leaves of the type represented by ,s4 rhoifolia have a wide geographical distribution4 ,the specimens described by ,feistmantel from the ,damuda series of ,india as ,sagenopteris longifolia are no doubt fronds of ,glossopteris longifolia#abej4 ,the ,wealden species ,sagenopteris ,mantelli 7,dunk47#abea agrees closely in habit and in the form of the leaflets with ,s4 ,phillipsi and ,s4 rhoifolia4 ,it is probable that some of the leaves described by ,velenovsk#abeb from ,lower ,cretaceous rocks in ,bohemia as ,thinnfeldia variabilis are portions of ,sagenopteris fronds4 ,s4 ,mantelli is recorded from several ,european localities1 from ,california#abec1 and elsewhere4 ,sagenopteris appears to have been widely distributed during the ,rhaetic1 ,jurassic and ,lower ,cretaceous floras4 ,the very great similarity between the specimens recorded from these three formations renders the genus an uncertain guide in regard to geological age4 ,decisive evidence as to its position in the plant kingdom is at present lacking3 the inclusion of the genus as a possible member of the ,hydropterideae has still to be justified4 ,,chapter ,,xxvii4 ,,genera ,,of ,,pteridosperms1 ,,ferns1 ,,and ,,plantae ,,incertae ,,sedis4 ,the genera and species described in this ,chapter are founded on sterile leaves or portions of leaves1 and in the great majority of cases the reproductive organs are either imperfectly known or have still to be discovered4 ,some of the genera1 the smaller number1 are no doubt true ferns1 while most of them may safely be regarded as plants which will ultimately be shown to belong to some other group1 in most cases that of the ,pteridosperms4 ,it is possible that a few of the types may be members of the ,cycadophyta rather than of the ,pteridospermeae1 but evidence as to systematic position is for the most part of a negative kind or too incomplete to lead to any definite expression of opinion as to the cycadean or pteridosperm nature of the imperfectly known ,palaeozoic or ,mesozoic species4 ,many of the genera are of little botanical interest1 though even the most problematical are of importance as criteria of geological age4 ,genera which there is good reason for including in the ,pteridosperms are dealt with in this section1 in order that the ,chapter in ,volume ,,iii4 devoted to this important group may be limited to more completely known types4 ,in most text-books it is customary to employ family names for sterile fern-like fronds which possess similar venation features or have in common certain vegetative characters1 the value of which it is impossible to estimate4 ,in the following account family or group names are not adopted1 on the ground that such slight utility as they may have is more than counterbalanced by the risk attending a grouping under one name of plants which may agree only in unessential characters4 ,the practice of classifying fossil plants has been carried to excess4 ,grouping together genera as a matter of convenience unavoidably creates a prejudice in favour of actual relationship1 which may or may not exist4 ,taeniopteris4 ,this generic name was instituted by ,brongniart#abed for simple linear or broadly linear leaves with a prominent midrib from which secondary veins1 simple or dichotomously branched1 are given off at right angles or obliquely4 ,the frond of the type-species ,taeniopteris vittata 7fig4 #ccb71 characteristic of ,jurassic floras1 was compared by ,brongniart with the pinnules of ,danaea and ,angiopteris4 ,among recent ferns the ,taeniopteris form of frond and venation is represented by ,oleandra neriiformis1 ,asplenium nidus1 and many other species4 ,though usually applied to fronds which there is good reason for regarding as simple leaves1 the generic designation ,taeniopteris has been extended to include pinnate fronds1 e4g4 the ,upper ,palaeozoic species ,t4 jejunata ,grand',eury1 and ,t4 ,carnoti ,ren4 and ,zeill4 7fig4 #ccj1 ,a74 ,the compound fronds from the ,lower ,coal-,measures of ,missouri described by ,dr ,white#abee as ,t4 missouriensis are characterised by decurrent and confluent ,taeniopteroid pinnules4 ,in a later reference#abef to this plant ,white pertinently adds1 8perhaps it belongs more properly in ,alethopteris40 ,leaves of the ,taeniopteris type are described by several authors as species of ,oleandridium1 ,angiopteridium1 ,danaeites1 ,marattia1 and other genera4 ,in such species of ,taeniopteroid leaves as have been dealt with in a former ,chapter1 the occurrence of sori justifies the substitution of a name denoting a close relationship to existing members of the ,marattiaceae1 but in the absence of fertile specimens the provisional designation ,taeniopteris should be retained4 ,it is often difficult to decide between ,taeniopteris and ,nilssonia as the more suitable name to apply to fragments of fossil leaves of ,mesozoic age4 ,taeniopteris is1 however1 distinguished from the ,cycadean genus by the greater prominence of the rachis1 also by the dichotomous branching of the secondary veins1 usually close to their origin and at varying distances between the axis of the frond and the edge of the lamina4 ,the genus ,taeniopteris1 though most abundant in ,rhaetic and ,jurassic strata1 occurs also in ,upper ,carboniferous and ,lower ,permian rocks4 ,the generic name ,macrotaeniopteris instituted by ,schimper#abeg has been used for leaves differing only in size from the usual type of ,taeniopteris1 but there is no adequate reason for its retention4 ,the species included in ,taeniopteris afford no satisfactory evidence as to their systematic position4 ,it is obviously unwise to adopt such generic titles as ,oleandridium1 ,marattiopsis1 etc41 merely because of resemblance in the venation of sterile fragments to ,oleandra or ,marattiaceous ferns4 ,some specimens of ,taeniopteris fronds described by ,mr ,sellards#abeh from ,permian rocks of ,kansas1 which are referred to later1 have furnished unconvincing evidence of reproductive organs4 ,taeniopteris multinervis1 ,weiss4 ,fig4 #cbi1 ,a1 ,b4 ,the late ,dr ,weiss#abei instituted this species 7which he designated ,taeniopteris multinervia1 though the specific name multinervis is constantly used7 for a fragment of a leaf from the ,lower ,permian of ,lebach characterised by numerous forked veins given off at right angles from a prominent rachis 7fig4 #cbi1 ,b74 ,this type of frond is recorded from the ,permian of ,trienbach 7,alsace7 by ,zeiller#abfj1 by ,renault#abfa and ,zeiller#abfb from the ,upper ,carboniferous of ,autun1 and from other localities4 ,the lamina of the simple leaf reaches a breadth of #f cm4 and a length of #dj cm4 7fig4 #cbi1 ,a72 the numerous secondary veins 7#be-cf per cm4 of lamina7 are either at right angles to the rachis or given off at an acute angle4 ,the mesophyll consists of polygonal cells some of which are elongated at right angles to the surface of the lamina4 ,a very similar form is described by ,fontaine and ,white from the ,permian of ,virginia as ,t4 ,lescuriana#abfc4 ,illustration3 ,,fig4 #cbi4 ,a4 ,taeniopteris multinervis1 ,weiss4 7 nat4 size4 ,after ,zeiller47 ,b4 ,t4 multinervis4 7,enlarged4 ,after ,zeiller47 ,c4 ,lesleya ,delafondi4 7 #b4 ,after ,zeiller47 ,it is futile to expect to be able to separate the numerous ,taeniopteris leaves into well-defined species3 all we can do is to group the specimens under different names1 using as artificial distinctions such characters as the shape of the leaf1 the number of veins per centimetre1 and the prominence of the rachis4 ,another ,virginian species of ,permian age described by ,fontaine and ,white#abfd1 ,t4 ,newberriana1 is said to bear sori1 but no satisfactory information is given as to the nature of these organs4 ,specimens referred with some hesitation to this species and to a similar species1 ,t4 coriacea1 have been described by ,sellards#abfe from material obtained from ,permian beds in ,kansas4 ,the lamina of the simple linear fronds is characterised by the occurrence of small oval bodies half immersed in the substance of the leaf between the secondary veins 7figs4 #ccj1 ,d1 ,e74 ,one of these bodies is represented in an apparently dehisced condition in fig4 #ccj1 ,d4 ,sellards suggests the possibility that these bodies are sporangia1 but1 as he points out1 they afford no indication of cellular structure nor are they in direct connexion with the veins4 ,taeniopteris jejunata1 ,grand',eury#abff4 ,this species differs from ,t4 multinervis in its bipinnate fronds2 the linear or oval-linear pinnae are attached by a short stalk to the primary rachis and reach a length of #be cm42 the veins are less crowded1 #ab-ae per centimetre4 ,t4 jejunata is recorded from the ,coal-fields of the ,loire and ,commentry#abfg in ,france1 from the ,lower ,permian of ,thuringia#abfh1 and elsewhere4 ,taeniopteris ,carnoti1 ,ren4 and ,zeiller#abfi4 ,fig4 #ccj1 ,a4 ,this species1 founded on portions of pinnate fronds from the ,coal-field of ,commentry1 is characterised by rather broader 7#be-cj mm47 pinnules1 with short pedicels and a cordate base1 reaching a length of #be-cj cm4 ,the secondary forked veins are more numerous than in ,t4 jejunata4 ,in ,t4 multinervis the pinnules are still broader and have a stronger midrib4 ,several species of ,taeniopteris have been described from ,triasso-,rhaetic rocks in ,europe1 ,india1 ,tonkin and elsewhere4 ,in some cases it is practically impossible to recognise clear specific distinctions between ,rhaetic and ,jurassic types4 ,from the ,damuda and ,panchet series of ,india 7,triasso-,rhaetic7 ,feistmantel has described large sterile fronds as ,macrotaeniopteris ,feddeni#abgj which reach a breadth of #bj cm43 these may be compared with the ,indian species ,taeniopteris lata ,oldham#abga1 and to ,t4 gigantea from the ,rhaetic of ,franconia#abgb and ,scania4 ,a specimen of this species figured by ,nathorst#abgc from ,scania has a lamina #cc cm4 broad4 ,other examples are afforded by ,m4 ,wianamattae ,feist4#abgd from rocks of the same age in ,australia and by ,taeniopteris superba ,sap4#abge from ,lower ,rhaetic rocks near ,autun4 ,from the ,rhaetic of ,tonkin1 ,zeiller records several species1 among which may be mentioned ,t4 ,jourdyi ,zeill4#abgf and ,t4 spatulata ,mac,clelland 7fig4 #ccj1 ,b1 ,c74 ,both have simple fronds4 ,those of ,t4 ,jourdyi reach a length of #aj-dj cm4 and a breadth of #aj-gj mm42 the rachis is characterised by crowded and discontinuous transverse folds1 and the secondary veins 7#ce-ej per cm47 are usually at right angles to the rachis4 ,this ,tonkin species is compared by ,zeiller with the ,european ,rhaetic species ,t4 tenuinervis ,brauns4 ,the polymorphism of the fronds is a striking feature3 in one case described by ,zeiller the lamina appears to be divided into segments like those characteristic of the leaf of the ,cycadean genus ,anomozamites4 ,it is obviously difficult in many instances to distinguish between detached ,taeniopteroid pinnae of a compound frond and complete simple leaves4 ,in some compound fern fronds1 as in the recent ,polypodiaceous genus ,didymochlaena1 the pinnules are deciduous1 and the same feature undoubtedly characterised the fronds of many extinct species4 ,a specimen figured by ,zeiller which shows several petioles of ,t4 ,jourdyi attached to a thick stem#abgg demonstrates the simple nature of the leaves4 ,in other cases1 e4g4 ,t4 vittata1 specimens occur in which the slightly enlarged petiole-base has a clean-cut surface indicating abscission from a rhizome 7fig4 #ccb74 ,the fronds described by ,zeiller as ,t4 spatulata#abgh 7fig4 #ccj1 ,b1 ,c7 closely resemble ,jurassic leaves from ,victoria referred to ,taeniopteris ,daintreei ,mc,coy#abgi4 ,illustration3 ,,fig4 #ccj4 ,a4 ,taeniopteris ,carnoti1 ,ren4 and ,zeill4 7,nat4 size4 ,after ,renault and ,zeiller47 ,b4 ,t4 spatulata1 ,mc,clell4 7,nat4 size4 ,after ,zeiller47 ,c4 ,t4 spatulata4 7 #c4 ,after ,zeiller47 ,d4 ,supposed sporangium of ,t4 coriacea4 7 #ae4 ,after ,sellards47 ,e4 ,t4 coriacea4 7 #b4 ,after ,sellards47 ,whether specifically identical or not1 these leaves represent a type distinguished from the other species of the genus by the small breadth of the linear-lanceolate or linear-spathulate lamina1 which may be #f-ae cm4 in length and #c-ab mm4 broad4 ,the lamina is often characterised by transverse folds 7fig4 #ccj1 ,c74 ,taeniopteris ,carruthersi4 ,fig4 #cca4 #ahgb4 ,taeniopteris ,daintreei1 ,carruthers1 ,quart4 ,journ4 ,geol4 ,soc4 ,vol4 ,,xxviii4 ,pl4 ,,xxvii4 fig4 #f4 #ahhc4 ,t4 ,carruthersi1 ,tenison-,woods1 ,proc4 ,linn4 ,soc4 ,n4 ,s4 ,wales1 ,vol4 ,,viii4 p4 #aag4 ,illustration3 ,,fig4 #cca4 ,taeniopteris ,carruthersi1 ,ten4-,woods4 ,nat4 size4 ,the simple fronds included under this specific name are characterised by a strong midrib from which numerous simple or forked secondary veins are given off at a right angle or slightly inclined4 ,the breadth of the lamina decreases gradually towards the petiole4 ,the ,australian species named by ,mc,coy ,taeniopteris ,daintreei1 to which ,carruthers referred the ,queensland fossils1 has a much narrower and more linear form of frond1 and for this reason ,tenison-,woods instituted a new specific name4 ,t4 ,carruthersi represents a form of leaf met with in ,rhaetic1 or possibly ,upper ,triassic1 rocks in ,s4 ,africa#abhj and ,australia4 ,a very similar1 perhaps an identical type1 was described from ,argentina by ,geinitz#abha as ,t4 mareyiaca3 among many other examples of this form of frond may be mentioned ,t4 immersa#abhb ,nath4 from the ,rhaetic rocks of ,scania and ,t4 virgulata from the ,rhaetic of ,tonkin#abhc4 ,a comparison of ,taeniopteris ,carruthersi or various other 8species0 of ,rhaetic fronds with the ,jurassic species ,t4 vittata illustrates the slight and unimportant differences on which specific separation is based4 ,it is hopeless to attempt to draw a satisfactory distinction between the numerous ,taeniopteris fronds from ,upper ,triassic and ,jurassic rocks4 ,taeniopteris vittata1 ,brongniart4 ,fig4 #ccb4 ,the simple leaves to which ,brongniart applied this name are characteristic of the ,inferior ,oolite flora of ,england1 and examples of the same type are recorded from ,jurassic rocks of ,india1 ,poland1 the ,arctic regions1 ,japan1 ,china1 ,australia and other countries#abhd4 ,leaf linear-lanceolate1 reaching a length of more than #bj cm4 and a breadth of #c cm4 ,the lamina increases gradually in breadth from the base and tapers towards the apex4 ,numerous secondary veins are given off at right angles from a broad midrib3 the lateral veins may be simple or forked close to their origin1 near the margin1 or in the intermediate portion1 of the lamina4 ,it is exceedingly difficult to use ,taeniopteris leaves of this form as evidence in regard to the ,jurassic or ,rhaetic age of plant-bearing strata4 ,the species ,t4 tenuinervis ,brauns1 as figured by ,schenk#abhe from the ,rhaetic rocks of ,germany and ,persia1 and recorded from several other regions1 presents a close agreement with ,t4 vittata4 ,oleandridium lentriculiforme ,etheridge#abhf from the ,hawkesbury series of ,australia is another similar leaf4 ,the species ,t4 vittata from the ,yorkshire coast1 represented in fig4 #ccb1 shows a well-preserved petiole with a clean-cut base like that of the petioles of ,oleandra neriiformis and other recent ferns which are detached from the rhizome by the action of an absciss-layer4 ,illustration3 ,,fig4 #ccb4 ,taeniopteris vittata4 7,british ,museum ,no4 #cibag4 nat4 size47 ,a broader form of frond with similar venation was described by ,lindley and ,hutton#abhg as ,taeniopteris major4 ,an examination of the type-specimen from the ,inferior ,oolite of ,yorkshire1 now in the ,manchester ,museum1 led me to doubt the necessity of specific separation from ,t4 vittata#abhh4 ,a smaller frond of the same general type as ,t4 vittata is recorded from ,wealden strata of ,north ,germany and ,england under the name ,t4 ,beyrichii#abhi4 ,weichselia4 ,this generic name was instituted by ,stiehler#abij for impressions of bipinnate sterile fronds1 presumably ferns1 from ,lower ,cretaceous rocks near ,quedlinburg4 ,the same type of leaf from ,english ,wealden beds had previously been referred by ,mantell and other authors to ,pecopteris1 and by ,brongniart to his genus ,lonchopteris#abia4 ,it is1 however1 advisable to follow ,nathorst's example#abib and restrict the latter name to ,palaeozoic species4 ,as already suggested1 it would obviate confusion to substitute a new generic designation for ,lonchopteris in the case of ,triassic species which are probably members of the ,osmundaceae4 ,the type-species of ,stiehler1 ,weichselia ,ludowicae#abic1 does not differ in any important character from ,weichselia ,mantelli1 the species originally described by ,stokes and ,webb from the ,wealden of ,england as ,pecopteris reticulata4 ,weichselia ,mantelli 7,brongn47#abid4 ,fig4 #ccc4 #ahbd4 ,pecopteris reticulata1 ,stokes and ,webb1 ,trans4 ,geol4 ,soc4 #b4 ,vol4 ,i4 p4 #dbc1 ,pls4 ,,xlvi4 ,,xlvii4 #ahbh4 ,lonchopteris ,mantelli1 ,brongniart1 ,prod4 p4 #f2 ,hist4 vg4 foss4 p4 #cfi1 ,pl4 ,,cxxxi4 #ahid4 ,weichselia ,mantelli1 ,seward1 ,wealden ,flora1 ,vol4 ,i4 p4 #aad4 ,pl4 ,x4 fig4 #c4 #ahii4 ,weichselia reticulata1 ,fontaine1 in ,ward1 ,ann4 ,rep4 ,u4 ,s4 ,geol4 ,surv4 p4 #fea4 ,frond bipinnate1 rachis broad2 pinnae very long1 of uniform breadth and with prominent axes2 pinnules crowded1 entire1 with obtuse apex1 usually oblong but more or less triangular or rounded towards the distal ends of the pinnae4 ,the pinnules1 which may reach a length of #i cm41 are characterised by a fleshy lamina attached by the whole breadth of the base2 the two rows of segments on each secondary rachis are usually inclined towards one another so that they form with the axis of the pinna a wide-open ,v instead of lying in one plane 7fig4 #ccc1 ,c74 ,from a median rib are given off numerous anastomosing branches 7fig4 #ccc1 ,b74 ,illustration3 ,,fig4 #ccc4 ,weichselia ,mantelli4 ,a4 ,part of a frond from the ,wealden of ,sussex1 ,england4 7,british ,museum2 v4 #bfcj4 nat4 size47 ,b4 ,pinnule from ,bernissart1 ,belgium 7 #c74 ,c4 ,weichselia erratica1 ,nath4 ,section of pinna4 7,after ,nathorst47 ,this characteristic ,wealden species is recorded from ,england1 ,germany1 ,france1 ,belgium1 ,austria1 ,russia1 ,bornholm1 ,north ,america1 and ,japan4 ,it is by no means certain that ,weichselia ,mantelli is a true fern3 no satisfactory evidence of fructification has been adduced4 ,the broad and strong rachis is comparable with that of a ,cycadean leaf and the thick lamina suggests a plant of xerophilous habit4 ,i have retained the specific name ,mantelli on the ground of long established usage instead of following ,fontaine in his adherence to strict priority4 ,glossopteris4 ,the name ,glossopteris was proposed by ,brongniart in #ahbbabie for an imperfect leaf-impression which he called ,filicites 7,glossopteris7 dubius1 but the specimen so named has since been identified as part of a sporophyll of a ,lepidostrobus4 ,the author of the genus afterwards published#abif a diagnosis1 based on well-preserved leaves from ,permo-,carboniferous rocks in ,australia and ,india1 of the type-species ,glossopteris ,browniana1 the ,indian examples being distinguished as ,g4 ,browniana var4 indica while the ,australian form was named ,g4 ,browniana var4 australasica4 ,schimper#abig afterwards raised the ,indian fossils to specific rank as ,g4 indica though some authors#abih have continued to consider the two forms as insufficiently distinct to be regarded as different species4 ,the genus ,glossopteris may be defined as follows3 ,leaves simple1 varying considerably in size1 shape1 and venation characters1 but almost without exception characterised by repeatedly anastomosing lateral veins4 ,the leaves are of two kinds3 7i7 foliage leaves2 apparently always sterile1 usually spathulate1 with an obtuse apex1 a well-marked midrib which may persist to the apex or die out in the upper half of the lamina1 characterised by its slight prominence and comparatively great breadth especially in the basal part of the frond4 ,in most cases the lamina extends as a narrow margin to the leaf-base1 but in a few forms there is a short petiole 7fig4 #ccd74 ,though usually spathulate1 the frond may be linear-lanceolate1 or ovate2 the apex is sometimes acute4 ,leaves vary in length from #c to #dj cm4 and may in larger forms have a breadth of #aj cm4 ,numerous lateral veins curve upwards and outwards to the margin of the lamina or pursue a straight course almost at right-angles to the midrib4 7ii7 ,scale-leaves#abii which differ from the foliage-leaves in their much smaller size and in the absence of a midrib2 they are deltoid1 oval or cordate in shape and generally terminate in an acute apex2 the edge of the lamina may be slightly incurved so that the leaf presents a convex upper surface supplied with anastomosing veins4 ,the scale-leaves1 which vary in length from about #a to #f cm41 probably acted as sporophylls4 ,the only evidence as to the nature of the fructification so far obtained is represented by empty sporangium-like organs 7#ab-ae mm4 long by #jf-jh mm4 broad7 frequently associated with the scale-leaves#acjj4 ,the leaves1 in some cases at least1 were borne near together on a cylindrical stem or rhizome which produced branched adventitious roots#acja4 ,the fossils long known as ,vertebraria were recognised by ,zeiller#acjb and by ,oldham#acjc as the stems of ,glossopteris4 ,the systematic position of ,glossopteris must for the present be left an open question4 ,though usually spoken of as a fern1 it is noteworthy that despite the enormous abundance of its foliage leaves in the ,permo-,carboniferous strata of ,india1 ,australia1 ,south ,africa1 and ,south ,america1 no single example has been discovered which shows undoubted remains of sori or sporangia4 ,many authors have described fertile leaves of ,glossopteris2 but it was not until ,arber's discovery of sporangia in close association with the scale-leaves that any light was thrown on the nature of the reproductive organs4 ,the probability is that ,glossopteris was not a true fern but a member of that large and ever-increasing class1 the ,pteridosperms4 ,this opinion is based largely on negative evidence4 ,such sporangia as have been described may have contained microspores and the plant may have been heterosporous4 ,the occurrence of seeds in association with ,glossopteris fronds recorded by more than one writer#acjd1 though by no means decisive and possibly the result of chance association1 is favourable to this view4 ,dr ,white#acje has suggested that the small leaves described by ,zeiller#acjf as ,ottokaria bengalensis from ,lower ,gondwana 7,permo-,carboniferous7 rocks of ,india1 and similar fossils recorded by himself from ,brazil as ,o4 ovalis1 may represent 8sporangiferous0 organs of ,glossopteris or ,gangamopteris1 8both of which are probably pteridospermic40 ,there is1 however1 no conclusive evidence in support of this suggestion4 ,the genus1 whatever its position may be1 has a special interest for the geologist and for the student of plant distribution2 it is a characteristic member of a ,permo-,carboniferous flora which flourished over an enormous area1 including ,india1 ,south ,africa1--extending from ,cape ,colony to ,rhodesia and ,german ,east ,africa#acjg1--;,australia1 and ,south ,america#acjh4 ,this flora1 known as the ,glossopteris flora1 differed considerably in its component genera from that which overspread ,europe and ,north ,america and some more southern regions in the ,upper ,carboniferous and ,permian periods4 ,the discovery by ,amalitzky#acji of ,glossopteris1 and other genera characteristic of the ,glossopteris flora1 in the ,upper ,permian rocks in ,vologda 7,russia7 demonstrates the existence of a northern outpost of the southern botanical province1 and ,zeiller's discovery of the genus in the ,rhaetic flora of ,tonkin#acaj shows that ,glossopteris persisted beyond the limits of the ,palaeozoic epoch4 ,dr ,david ,white#acaa has recently proposed to re-christen the ,glossopteris flora the ,gangamopteris flora on the ground that ,gangamopteris is strictly ,palaeozoic in its range1 whereas ,glossopteris persisted into the ,mesozoic era2 this is perhaps hardly a sufficient reason for giving up so well established a title as the ,glossopteris flora4 ,a fuller account of this southern flora must be reserved for another volume4 ,glossopteris ,browniana1 ,brongniart#acab4 ,figs4 #ccd-cf4 ,the specific name ,browniana is now applied to obtusely pointed leaves which sometimes reach a length of #ae cm41 but are usually rather shorter4 ,in form and venation they closely resemble the leaves of the recent genus ,antrophyum and species of ,acrostichum4 ,the comparatively broad midrib may be replaced in its proximal portion by several parallel veins3 from it are given off numerous lateral veins which form a reticulum characterised by meshes approximately equal in size and elongated in a direction parallel to the general course of the secondary veins 7fig4 #ccd74 ,illustration3 ,,fig4 #ccd4 ,glossopteris ,browniana1 ,brongn4 ,a4 ,nat4 size3 ,b #c4 ,the drawings1 originally published by ,zeiller#acac1 reproduced in fig4 #cce illustrate the venation and its range of variation2 the meshes are usually hexagonal and arranged as shown in figs4 ,a and ,b1 but occasionally 7fig4 #cce1 ,c7 they follow a more steeply inclined course4 ,small leaves with a more or less distinct midrib1 #b-c cm4 in length1 supply transitional stages between foliage- and scale-leaves4 ,in the true scale-leaves spreading and occasionally anastomosing veins take the place of the midrib and lateral veins of the ordinary frond4 ,mc,coy#acad in describing some ,australian specimens of ,glossopteris in #ahdg spoke of scale-like appendages of the rhizome which he compared with the large ramenta of ,acrostichum and other ferns4 ,it was1 however1 ,zeiller#acae who first recognised the leaf-nature of these scales and adequately described them2 additional figures of scale-leaves have been published by ,mr ,arber#acaf and by myself#acag4 ,the importance of these small leaves has been considerably increased by ,mr ,arber's discovery of associated sporangia which1 as he suggests1 were probably borne on their lower concave surface4 ,illustration3 ,,fig4 #cce4 ,glossopteris ,browniana1 ,brongn4 7,after ,zeiller4 #b47 ,the sporangia 7fig4 #ccf7 are compared by ,arber with the microsporangia of recent ,cycads and with the ,palaeozoic sporangia described by ,zeiller as ,discopteris ,rallii 7fig4 #bef1 ,d72 the latter are distinguished by the well-defined group of thicker walled cells representing the annulus of true fern sporangia4 ,we know nothing as to the contents of the ,glossopteris sporangia1 whether they contained microspores or whether they are the spore-capsules of a homosporous plant4 ,illustration3 ,,fig4 #ccf4 ,glossopteris ,browniana1 ,brongn4 ,sporangia4 7 #cj74 ,after ,arber4 ,the rhizome of ,glossopteris ,browniana has been described in detail by ,zeiller1 who first demonstrated that the fossils originally assigned by ,royle#acah to the genus ,vertebraria represent the stem of this and1 as we now know1 of some other species of ,glossopteris4 ,vertebraria occurs in abundance in ,permo-,carboniferous strata in association with ,glossopteris2 the differences between ,australian1 ,indian1 and ,south forms1 though expressed by specific names1 are insignificant4 ,the stems are usually preserved in the form of flattened1 single or branched1 axes sometimes bearing slender branched roots and characterised by one or two1 or less frequently three1 longitudinal grooves or ridges 7fig4 #ccg7 from which lateral grooves or ridges are given off at right angles1 dividing the surface into more or less rectangular areas #a cm4 or more in length4 ,the surface of these areas is often slightly convex and in some specimens the outlines of cells may be detected4 ,mr ,oldham has described some interesting examples of ,vertebraria from ,india in which the longitudinal and transverse grooves are occupied by a dark brown ferruginous substance or by the carbonised remains of plant-tissues 7fig4 #cch1 ,c1 ,d74 ,in transverse section1 a ,vertebraria cast appears to be divided into a number of wedge-shaped segments radiating from a common centre4 ,prof4 ,zeiller#acai has figured specimens of ,vertebraria with portions of ,glossopteris fronds still attached4 ,illustration3 ,,fig4 #ccg4 ,vertebraria indica1 ,royle4 ,nat4 size4 7,after ,feistmantel47 ,the rhizome of ,glossopteris1 as represented by the ,vertebraria casts1 is aptly compared by ,zeiller#acbj with that of the recent ,polypodiaceous fern ,onoclea struthiopteris4 ,sections of the recent stem 7fig4 #cch1 ,e1 ,f7 show that the form is irregularly stellate owing to the presence of prominent wings which anastomose laterally at intervals as shown by the examination of a series of sections4 ,the leaf-traces are derived from the steles of adjacent wings4 ,fig4 #cch 7,b and ,a7 represents somewhat diagrammatically a longitudinal and transverse view of a ,vertebraria2 the radiating arms represented in the transverse section 7fig4 ,a7 are the stem ribs or wings and the segments between them are intrusions of sedimentary material4 ,the rectangular areas characteristic of the surface of a ,vertebraria are the intruded segments of rock3 these are separated at intervals by transverse grooves1 which mark the course of vascular strands given off at each anastomosis of the longitudinal wings to supply the leaves4 ,illustration3 ,,fig4 #cch4 ,a1 ,b4 ,vertebraria indica4 7,after ,zeiller47 ,c1 ,d4 ,v4 indica4 7,nat4 size4 ,after ,oldham47 ,e1 ,f4 ,onoclea struthiopteris4 7 #b4 ,after ,zeiller47 ,mr ,oldham1 who discovered the connexion between ,glossopteris and ,vertebraria independently of ,dr ,zeiller1 does not agree with the interpretation of the structural features of the rhizome which ,zeiller bases on a comparison between ,vertebraria and ,onoclea struthiopteris4 ,oldham#acba describes ,vertebraria as consisting of a central axis 8joined to an outer rind by a series of radial septa10 the spaces between the septa being divided into chambers by transverse partitions4 ,his view is that the rhizome of ,glossopteris was a cylindrical organ and not an irregularly winged axis like the stem of ,onoclea4 ,zeiller#acbb has replied in detail to ,oldham's interpretation and adheres to his original view1 that the rhizome consisted of a solid axis with radial wings or flanges which at intervals anastomosed transversely in pairs at the nodes4 ,it may1 however1 be possible that the spaces between the longitudinal and transverse grooves on a ,vertebraria axis1 which have been filled with the surrounding rock1 were originally occupied in part at least by secondary wood1 and the transverse strips of carbonaceous material#acbc lying in the grooves may represent medullary-ray tissue and accompanying leaf-traces4 ,the longitudinal striations seen in some specimens of ,vertebraria on the areas between the grooves may be the impressions of woody tissue4 ,it is impossible without the aid of more perfectly preserved material to arrive at a satisfactory conception of the structural features of a complete ,glossopteris rhizome4 ,illustration3 ,,fig4 #cci4 ,glossopteris fronds attached to rhizome4 7,from a specimen lent by ,dr ,mohlengraaff4 ,considerably reduced47 ,in the specimen of ,glossopteris ,browniana shown in fig4 #cci several leaves are attached to an axis which shows none of the surface-features of ,vertebraria4 ,i am indebted to the kindness of ,dr ,mohlengraaff of ,delft for the loan of this specimen which was obtained from ,permo-,carboniferous rocks in the ,transvaal4 ,an axis figured by ,etheridge#acbd from an ,australian locality bears a tuft of ,glossopteris leaves1 possibly ,g4 ,browniana2 in place of the rectangular areas characteristic of ,vertebraria it shows transversely elongated leaf-scars or1 on the internal cast1 imbricate rod-like projections which ,etheridge suggests represent vascular bundles4 ,glossopteris indica1 ,schimper4 ,figs4 #cdj1 ,a1 #cda4 ,it is a question of secondary importance whether or not the fronds which ,brongniart spoke of as a variety of ,glossopteris ,browniana should be recognised as specifically distinct4 ,the careful examination by ,zeiller of the venation characters has1 however1 afforded justification for separating ,g4 ,browniana and ,g4 indica4 ,we must admit that the slight and not very constant differences in the size and form of the meshes produced by the anastomosing of the lateral veins are characters which cannot be recognised as having more than a secondary value1 though1 as a matter of convenience1 we employ them as aids to determination4 ,the arbitrary separation of sterile leaves1 which differ by small degrees from one another in form and in the details of venation1 by the application of specific names is a thankless task necessitated by custom and convenience2 it is1 however1 idle to ignore the artificial basis of such separation4 ,mr ,arber has recently published1 in his valuable ,glossopteris ,flora1 an analytical key which serves to facilitate the description and determination of different types of frond#acbe4 ,illustration3 ,,fig4 #cdj4 ,a4 ,glossopteris indica1 ,schimper4 7 nat4 size47 ,b4 ,glossopteris angustifolia1 ,brongniart4 7,nat4 size47 ,from ,arber1 after ,feistmantel4 ,the large leaves of ,glossopteris indica1 reaching a length in extreme cases of #dj cm4 and a breadth of #aj cm41 are characterised by a rather greater regularity in the arrangement of the meshes and by the greater parallelism of the upper and lower sides of each mesh 7fig4 #cda7 and by less difference in size between the venation meshes than in ,g4 ,browniana1 the leaves of which are usually smaller4 ,the relatively thick epidermis consists of rectangular cells with stomata in depressions#acbf4 ,the scale-leaves#acbg1 rather larger than those of ,g4 ,browniana1 are more or less rhomboidal with rounded angles and reach a length of #ae-f cm4 and a breadth of #ae-be cm4 ,the rhizome is practically identical with that of ,g4 ,browniana#acbh4 ,illustration3 ,,fig4 #cda4 ,glossopteris indica1 ,schimp4 7 #a47 ,from ,arber1 after ,zeiller4 ,this species occurs in great abundance in the ,permo-,carboniferous rocks of ,india1 ,australia1 and in various parts of ,south ,africa1 and elsewhere4 ,it has been recognised also by ,amalitzky#acbi in ,upper ,permian beds in ,russia and by ,zeiller in the ,rhaetic series of ,tonkin#accj4 ,illustration3 ,,fig4 #cdb4 ,glossopteris angustifolia var4 taeniopteroides4 7 #c47 ,glossopteris angustifolia1 ,brongniart4 ,figs4 #cdj1 ,b2 #cdb4 ,it is convenient to retain this designation for linear fronds with an acute or obtuse apex and a venation-reticulum composed of long and narrow meshes 7fig4 #cdj1 ,b74 ,it is by no means unlikely1 as ,arber suggests1 that the same plant may have produced leaves of the ,g4 indica type and narrower fronds which conform to ,g4 angustifolia4 ,in his description of some ,indian specimens of ,g4 indica1 ,zeiller draws attention to the variation exhibited in regard to the extent of anastomosing between the secondary veins3 some examples with very few cross-connexions agree more closely with ,taeniopteris than with ,glossopteris as usually defined#acca4 ,the venation shown in fig4 #cdb illustrates an extreme case of what is almost certainly a ,glossopteris leaf of the ,g4 angustifolia type4 ,this specimen1 which was discovered by ,mr ,leslie in the ,permo-,carboniferous sandstone of ,vereeniging 7,transvaal71 has been referred to a variety of ,brongniart's species as ,g4 angustifolia var4 taeniopteroides#accb on account of the almost complete absence of any cross-connexions4 ,the reference to ,glossopteris1 which my friend ,dr ,zeiller suggested1 is amply justified by the form of the leaf as a whole1 by the angle at which the lateral veins leave the midrib1 a feature in contrast to the wider angle at which the lateral veins are usually given off in ,taeniopteris 7figs4 #cbi1 #ccb71 and by the similarity to the ,indian specimens already mentioned4 ,several authors have described leaves or leaflets under the generic name ,megalopteris#accc from ,carboniferous and ,permian rocks which bear a close resemblance to the ,south ,african variety1 but in some cases at least ,megalopteris is known to be a pinnate and not a simple leaf4 ,the leaf figured by ,jack and ,etheridge as ,taeniopteris sp4#accd from ,queensland may also be an example of ,glossopteris4 ,comparison may be made also with the ,palaeozoic leaves described in the first instance by ,lesquereux and more recently by ,renault and ,zeiller as species of ,lesleya#acce 7fig4 #cdg74 ,illustration3 ,,fig4 #cdc4 ,blechnoxylon talbragarense1 ,eth43 s1 scale-leaves2 x1 secondary xylem4 7,after ,etheridge4 ,a #b2 ,b #c2 ,c much enlarged47 ,blechnoxylon talbragarense1 ,etheridge4 ,fig4 #cdc4 ,under this name ,etheridge#accf described some specimens from the ,permo-,carboniferous ,coal-,measures of ,new ,south ,wales1 which he regards as a fern1 comparable1 in the possession of a cylinder of secondary xylem1 with the recent genus ,botrychium and with ,lyginodendron and other members of the ,cycadofilices4 ,the slender axis 7#a-c mm4 in diameter7 appears to consist of a zone of radially disposed tissue 7fig4 #cdc1 ,c1 x71 which is probably of the nature of secondary xylem1 enclosing a pith and surrounded externally by imperfectly preserved remnants of cortex4 ,unfortunately no anatomical details could be made out1 but the general appearance1 if not due to inorganic structure1 certainly supports ,etheridge's determination4 ,the stem bore at intervals clusters of linear-lanceolate leaves 7reaching #ab mm4 in length7 in close spirals 7fig4 #cdc1 ,a and ,b72 the leaves are characterised by a strong midrib and forked secondary veins4 ,small 8pyriform0 bodies of the nature of scale-leaves occur in association with the fronds 7fig4 #cdc1 ,b1 s74 ,in his description of this interesting plant1 ,etheridge quotes an opinion which ,i expressed in regard to the comparison of the stem with those of ,botrychium1 ,lyginodendron1 and other genera4 ,no satisfactory evidence has been found as to the nature of the fructification4 ,although the leaves of ,blechnoxylon are much smaller than those of ,glossopteris1 ,i am now disposed to regard the genus as closely allied or even generically referable to ,glossopteris4 ,the crowded disposition of the leaves is like that in ,glossopteris1 shown in fig4 #cci and in the figures published by ,etheridge and by ,oldham2 the association of scale-leaves and foliage-leaves is another feature in common4 ,the absence of a reticulum of anastomosing veins can no longer be considered a fatal objection to the suggestion that the ,australian type may be a species of ,glossopteris4 ,if the view that ,blechnoxylon is not a distinct genus is correct1 the occurrence of secondary xylem is favourable to the opinion already expressed that ,glossopteris is more likely to be a ,pteridosperm than a true fern4 ,the data at present available render it advisable to retain ,mr ,etheridge's name3 the comparison with ,glossopteris lacks confirmation4 ,sidenote3 ,,blechnoxylon ,illustration3 ,,fig4 #cdd4 ,glossopteris retifera4 7,nat4 size4 ,from ,arber1 after ,feistmantel47 ,glossopteris retifera1 ,feist4 ,fig4 #cdd4 ,in some ,glossopteris leaves the anastomosing secondary veins form a coarser reticulum1 as in the example represented in fig4 #cdd4 ,the name ,g4 retifera was given by ,feistmantel#accg to ,indian fronds of this type2 similar forms have been described as ,g4 conspicua and ,g4 ,tatei4 ,the type illustrated by ,g4 retifera is recorded also from ,permo-,carboniferous rocks in ,zululand#acch1 ,natal1 the ,transvaal1 ,cape ,colony1 and the ,argentine4 ,gangamopteris4 ,in #ahdg ,mc,coy#acci described a leaf-fragment from ,permo-,carboniferous rocks in ,new ,south ,wales as ,cyclopteris angustifolia4 ,the type-specimen of this species1 which is now in the ,sedgwick ,museum1 ,cambridge1 has been re-described by ,mr ,arber#acdj4 ,subsequently#acda ,mc,coy instituted the generic name ,gangamopteris for leaves1 like that previously referred by him to ,cyclopteris1 from the ,bacchus ,marsh ,sandstone1 of ,new ,south ,wales1 but he did not publish a diagnosis of the genus until several years later#acdb4 ,feistmantel#acdc1 who has described many species of ,gangamopteris from the ,lower ,gondwana strata of ,india1 slightly modified the original diagnosis4 ,the genus is represented by sterile fronds only4 ,we know nothing of the stem1 and such evidence as is available in regard to the form of the fertile leaves is of a circumstantial kind4 ,it is1 however1 highly probable that ,gangamopteris is not a true fern but a ,pteridosperm4 ,leaves simple1 sessile1 varying in shape2 obovate or spathulate1 broadly lanceolate or rarely linear2 the apex is usually blunt 7fig4 #cde7 but occasionally gradually tapered4 ,in general appearance a ,gangamopteris leaf is similar to that of ,glossopteris indica1 the chief distinction being the absence of a midrib4 ,gangamopteris leaves are on the whole larger than those of ,glossopteris2 many of them reach a length of #bj cm4 and some of the large ,indian fronds are nearly #dj cm4 long4 ,the venation of ,gangamopteris shows a greater uniformity in the size and shape of the meshes than that of ,glossopteris4 ,the middle of the lamina1 especially in the lower part1 is occupied by a few vertical veins from which branches curve upwards and outwards towards the edge of the lamina4 ,the secondary veins are connected by frequent anastomoses and agree very closely with those of ,glossopteris4 ,the lamina becomes narrower towards the base1 which is either cuneate or in some cases slightly auriculate 7fig4 #cde74 ,as ,i have elsewhere pointed out#acdd1 the presence or absence of a midrib is not in itself a character of real taxonomic importance4 ,in the recent fern ,scolopendrium vulgare the frond has a prominent midrib1 while in ,s4 nigripes there is no median rib4 ,mr ,arber has expressed the opinion that 8it is extremely doubtful whether the genus ,gangamopteris should not be merged in ,glossopteris#acde40 ,the retention of the two names is1 however1 convenient1 and it would tend to confusion were we to carry to its logical conclusion the view that the recognised distinction between the two genera may not be a mark of generic difference4 ,gangamopteris is confined to ,palaeozoic strata1 a fact which leads ,white#acdf to speak of the ,gangamopteris rather than of the ,glossopteris ,flora4 ,it occurs in ,south ,america1 ,south ,africa1 ,australia1 and ,india1 extending as far north as ,kashmir2 it has been discovered by ,amalitzky in ,permian rocks of ,russia#acdg4 ,the ,russian rocks in which ,glossopteris and ,gangamopteris were found are no doubt of ,permian age4 ,in ,australia1 ,south ,africa1 ,brazil and ,argentina1 and in the ,indian ,coal-fields1 ,gangamopteris is a characteristic genus of ,lower ,gondwana rocks4 ,these strata are usually spoken of as ,permo-,carboniferous in order to avoid the danger of attempting on insufficient data a precise correlation with ,european formations4 ,feistmantel speaks of ,gangamopteris as most abundant in the ,talchir-,karharbri beds1 though it is represented also in the overlying ,damuda series4 ,in ,australia the genus occurs in rocks which correspond in position and in their plant fossils with the ,talchir-,karharbri beds of ,india2 similarly1 in ,south ,africa and ,south ,america the ,gangamopteris beds are homotaxial with those of ,india and ,australia4 ,the leaf described by ,carruthers#acdh from ,brazil as ,noeggerathia obovata 7the type-specimen is in the ,british ,museum7 is no doubt specifically identical with ,gangamopteris cyclopteroides ,feist4#acdi ,in a paper by ,mr ,hayden on ,gangamopteris beds in the ,vihi ,valley1 ,kashmir1 evidence is adduced in support of the conclusion that the rocks are 8not younger than ,upper ,carboniferous and may belong to the base of that subdivision or even to the ,middle ,carboniferous#acej40 ,it would seem that ,gangamopteris was a very widely spread genus during the latter part of the ,carboniferous period in the vast ,southern ,continent to which the name ,gondwana ,land is often applied1 and that it flourished in the ,southern ,flora during at least part of the ,permian period3 with other members of the ,glossopteris ,flora it migrated to the ,north where it has been preserved in ,permian rocks of ,northern ,russia4 ,the ,glossopteris ,flora must have had its birth in the ,southern hemisphere4 ,the conclusion seems inevitable that the leaves of ,glossopteris and ,gangamopteris in the shales and sandstones of ,india1 ,south ,africa1 ,south ,america1 and ,australia are relics of the vegetation of a continent of which these regions are the disjuncta membra4 ,darwin wrote to his friend ,hooker in #ahha1 8,i have sometimes speculated whether there did not exist somewhere during long ages an extremely isolated continent1 perhaps near the ,south ,pole#acea40 ,it is probable that ,gangamopteris is one of the genera which flourished on this continent4 ,gangamopteris cyclopteroides1 ,feistmantel#aceb4 ,fig4 #cde4 #ahgf4 ,feistmantel1 ,records ,geol4 ,surv4 ,india1 ,vol4 ,,ix4 ,pt iii4 p4 #gc4 ,the specimen represented in fig4 #cde illustrates the characters of this commonest representative of the genus4 ,illustration3 ,,fig4 #cde4 ,gangamopteris cyclopteroides1 ,feist4 7,nat4 size4 ,from ,arber1 after ,feistmantel47 ,gangamopteris kashmirensis1 ,seward4 #aije4 ,seward1 ,mem4 ,geol4 ,surv4 ,india1 ,vol4 ,,ii4 ,mem4 ii4 ,this type agrees closely with ,g4 cyclopteroides in size and in the form of the leaf1 but it is distinguished by the flatter form of the arch formed by the lateral veins1 by their greater inclination to the margin of the lamina1 and by the more acutely pointed apex of the lamina4 ,this species1 though not very sharply distinguished from ,g4 cyclopteroides1 is important as coming from beds which have been assigned on other than palaeobotanical evidence to an ,upper or possibly a ,middle ,carboniferous horizon#acec4 ,we have no definite information in regard to the nature of the reproductive organs of ,gangamopteris1 but such evidence as there is supports the view expressed by ,dr ,white#aced and shared by some other authors that ,gangamopteris and ,glossopteris should be assigned to the ,pteridosperms4 ,despite the abundance of ,gangamopteris leaves1 no fertile specimen has been discovered4 ,this negative evidence may prove to be as correct as that which led ,stur#acee to exclude ,neuropteris1 ,alethopteris and ,odontopteris from the ferns4 ,the only evidence of a positive kind is that furnished by ,dr ,david ,white in his recent ,report on the ,palaeozoic ,flora of ,south ,brazil4 ,this author describes some small ,aphlebia-like leaves under two new generic names ,arberia#acef and ,derbyella#aceg4 ,the differences between the two sets of specimens1 so far as can be determined from the reproductions of imperfect impressions1 are slight1 and it is by no means clear that a distinction of generic rank exists4 ,these scale-leaves are on the average about #b cm4 in length2 the lamina is oval or rounded and has more or less prominent lobes4 ,in ,derbyella there are indications of anastomosing veins4 ,the specimens referred to ,arberia minasica are1 as ,white points out1 very similar to the fossil described by ,feistmantel from ,lower ,gondwana rocks of ,india as probably a portion of an inflorescence of ,noeggerathiopsis#aceh4 ,feistmantel's specimen is represented in fig4 #cdf3 the curled lobes may have originally borne seeds4 ,in the ,brazilian examples the abruptly truncated lobes 8bear evidence of separation from reproductive bodies40 ,an important point is the association of these scale-leaves with ,gangamopteris fronds and with gymnospermous seeds of the ,samaropsis type4 ,on the leaves assigned to ,derbyella aurita circular depressions occur at the base of the lobes which are described as probably due to sporangia4 ,dr ,white's discovery gives us increased confidence in expressing the view that ,gangamopteris bore its reproductive organs on specialised leaves very different from the sterile fronds2 it also strengthens the suspicion that the genus is a member of the class of seed-bearing fern-like plants4 ,illustration3 ,,fig4 #cdf4 ,arberia sp4 7 ,noeggerathiopsis of ,feistmantel74 7,nat4 size4 ,after ,feistmantel47 ,lesleya4 ,this generic designation was instituted by ,lesquereux#acei for simple oval-linear leaves from the ,coal-,measures of ,pennsylvania4 ,the leaves so named are probably generically identical with the specimen doubtfully assigned by ,brongniart#acfj to the ,coal-,measures1 and made by him the type of the genus ,cannophyllites on the ground of a resemblance to the leaves of the recent flowering plant ,canna4 ,fig4 #cdg illustrates the form of a ,lesleya leaf from the ,coal-basin of ,gard1 named by ,grand',eury ,l4 simplicinervis#acfa1 a type in which the veins are frequently unbranched and not repeatedly forked as in most examples of the genus 7fig4 #cbi1 ,c74 ,the features of the genus are1 the oval-linear or lanceolate shape of the presumably simple frond1 its entire or1 in one species at least 7,l4 ,delafondi1 ,zeill471 finely dentate margin1 the stout rachis giving off at a very acute angle numerous dichotomously branched secondary veins4 ,in ,l4 ,delafondi 7fig4 #cbi1 ,c71 described by ,zeiller#acfb from the ,lower ,permian of ,autun1 the frond may reach a length of more than #bj cm4 and a breadth of #h cm4 ,similar species are represented by ,l4 ensis#acfc from the coal-field of ,commentry1 and ,l4 grandis#acfd from ,upper ,carboniferous rocks of ,north ,america4 ,the genus is characteristic of ,upper ,carboniferous and ,lower ,permian strata3 the form of the leaf and the direction of the secondary veins suggest comparison with ,glossopteris1 but in ,lesleya there are no cross-connexions between the veins4 ,nothing is known as to the fructification1 a fact which naturally evokes the opinion that the genus is a ,pteridosperm#acfe and not a true fern4 ,some years before the discovery of ,pteridosperms1 ,grand',eury#acff suggested that ,lesleya might be a ,gymnosperm2 his opinion being based on the woody nature of the rachis and on the simple venation of ,lesleya simplicinervis4 ,illustration3 ,,fig4 #cdg4 ,leslya simplicinervis1 ,grand',eury4 7,reduced3 after ,grand',eury47 ,neuropteridium4 ,in their monograph of fossil plants from the ,bunter ,series of the ,vosges1 ,schimper and ,mougeot#acfg described some pinnate leaves of ferns as species of the genus ,neuropteris4 ,in #ahfi ,schimper#acfh placed these in a new sub-genus ,neuropteridium1 in order to draw attention to the fact that their fronds appear to be simply pinnate and not bipinnate or tripinnate as in ,neuropteris4 ,the type-species of ,neuropteridium is ,n4 grandifolia ,sch4 and ,moug4 from the ,bunter ,sandstones of the ,vosges4 ,the genus includes ,triassic ,european species and the widely distributed ,permo-,carboniferous species from ,brazil#acfi originally described by ,carruthers as ,odontopteris ,plantiana4 ,it is probable that some ,carboniferous plants1 particularly species from the lower members of the formation1 referred to the genus ,cardiopteris1 are not genetically distinct from the ,indian and southern hemisphere type ,neuropteridium validum 7 ,odontopteris ,plantiana74 ,fronds pinnate1 linear2 a broad rachis bears pinnules which may be either semicircular or broadly linear with an entire or lobed margin4 ,the longer pinnules may exceed #f cm4 in length4 ,the pinnules agree with those of ,neuropteris in being attached by the median portion of the lamina and not by the whole base1 which is more or less auriculate4 ,in some cases the repeatedly forked veins diverge from the centre of the pinnule base2 in others there is a midrib which persists for a short distance only1 and in some species the more persistent median vein gives the segments a closer resemblance to those of ,neuropteris4 ,fructification unknown1 with the exception of obscure indications of sporangia 787 on the fertile leaves of a ,triassic species4 ,illustration3 ,,fig4 #cdh4 ,neuropteridium validum1 ,feist4 ,nat4 size4 ,from the ,karharbri ,coal-field1 ,india4 ,from ,arber1 after ,feistmantel4 ,neuropteridium validum4 7,feistmantel#acgj74 ,fig4 #cdh4 #ahfi4 ,odontopteris ,plantiana1 ,carruthers1 ,geol4 ,mag4 ,vol4 ,,vi4 p4 #i1 ,pl4 ,,vi4 figs4 #b1 #c4 #ahgh4 ,neuropteris valida1 ,feistmantel1 ,mem4 ,geol4 ,surv4 ,india1 ,foss4 ,flor4 ,gondwana ,syst41 ,vol4 ,,iii4 p4 #aj1 pl4 ,,ii4-,,vi4 #ahhj4 ,neuropteridium validum1 ,feistmantel1 ,ibid4 #b1 p4 #hd4 ,the specimen represented in fig4 #cdh illustrates the main features of ,neuropteridium validum4 ,this species is referred to by ,dr ,white#acga as ,n4 ,plantianum on the ground of priority1 and with a view to perpetuate the name of the ,english engineer ,nathaniel ,plant who discovered the species in a ,brazilian ,coal-field in the province of ,rio ,grande do ,sul4 ,feistmantel's specific name is however retained as being much better known4 ,an examination of ,mr ,plant's specimen in the ,british ,museum led me#acgb to speak of the ,brazilian species as identical with ,n4 validum described by ,feistmantel from ,lower ,gondwana rocks of ,india4 ,zeiller#acgc had previously drawn attention to the resemblance between the two sets of specimens4 ,the frond of ,n4 validum may exceed #ej cm4 in length4 ,the lower pinnules may be entire and semicircular in form while the upper and larger segments1 which may reach a length of #e or #f cm41 are characterised by broad lobes 7fig4 #cdh74 ,this type is represented in the flora of the ,talchir-,karharbri series 7,lower ,gondwana7 of ,india#acgd1 in ,permo-,carboniferous rocks of ,brazil and ,argentine#acge1 and in the sandstones of ,vereeniging on the borders of the ,transvaal and ,cape ,colony4 ,it is a characteristic member of the ,glossopteris ,flora and occurs in association with ,glossopteris and ,gangamopteris4 ,neuropteridium intermedium 7,schimper74 ,fig4 #cdi4 ,this species has been figured by ,schimper and ,mougeot#acgf from the ,bunter of the ,vosges and more fully described by ,blanckenhorn#acgg from the ,bunter beds of ,commern4 ,the pinnate leaves reach a length of #fe cm42 the lower semicircular pinnules pass gradually into broadly linear segments characterised by an auriculate base and a ,neuropteris type of venation 7fig4 #ced1 ,d1 ,e74 ,in the example reproduced in fig4 #cdi from one of ,blanckenhorn's figures1 the fronds are attached to a short and thick rhizome bearing roots and portions of old petioles4 ,illustration3 ,,fig4 #cdi4 ,neuropteridium intermedium 7,schimp474 7,after ,blanckenhorn4 nat4 size47 ,an example of another ,triassic species is afforded by ,neuropteridium grandifolium ,schimp4 and ,moug41 which agrees very closely with ,n4 validum in the size and shape of the pinnules4 ,the occurrence in ,lower ,mesozoic ,european rocks of fronds hardly distinguishable from the older southern species may be regarded as favourable to the view already expressed1 that some at least of the ,permo-,carboniferous plants migrated north of the ,equator4 ,the resemblance between the ,vosges ,triassic species of ,schizoneura#acgh and the examples of this genus recorded from the ,lower ,gondwana rocks of ,india affords additional evidence of a northern migration4 ,our knowledge of the reproductive organs of ,neuropteridium is practically nil4 ,there is no doubt that ,zeiller#acgi and ,blanckenhorn#achj are correct in regarding the ,bunter fronds assigned by ,schimper and ,mougeot to the genus ,crematopteris as the fertile leaves of ,neuropteridium intermedium or some other species from the same horizon4 ,these fronds bear crowded pinnules similar to those of ,neuropteridium intermedium1 ,n4 ,voltzii#acha1 and other species1 exhibiting on the exposed surface numerous carbonaceous spots which may be the remains of sporangia4 ,cardiopteris4 ,schimper#achb applied this generic name to ,lower ,carboniferous fronds of a simple-pinnate habit which had previously been described as species of ,cyclopteris4 ,cardiopteris frondosa may serve as a typical example4 ,this species1 originally described by ,goeppert as ,cyclopteris frondosa 7fig4 #cej71 is recorded from ,lower ,carboniferous rocks in the ,vosges district#achc in ,silesia1 ,moravia#achd1 and ,thuringia#ache4 ,the pinnules1 which are attached in opposite pairs to a broad rachis1 vary in length from #b to #aj cm4 and have a breadth of #b to #h cm42 in manner of attachment and venation they agree with those of ,neuropteridium validum4 ,the venation is very clearly shown in a drawing of some large pinnules figured by ,stur#achf4 ,the specimen of ,cardiopteris frondosa1 a portion of which is shown in fig4 #cej on a slightly reduced scale1 was originally figured by ,schimper from an unusually good example in the ,strassburg ,museum4 ,schimper's drawing hardly does justice to the original specimen4 ,a frond bearing rather narrower pinnules1 alternately placed on the rachis1 which ,fritsch has described as ,cardiopteris ,hochstetterii var4 franconica from the ,culm of ,thuringia1 bears a close resemblance to ,neuropteridium validum but differs in the entire margin of the pinnules4 ,an ,upper ,carboniferous species from ,russia described by ,grigoriew#achg as ,neuropteris1 cf4 cordata var4 densineura1 represents another form of similar habit4 ,illustration3 ,,fig4 #cej4 ,cardiopteris frondosa 7,goepp474 7 nat4 size4 ,after ,schimper47 ,schuster#achh has recently proposed a new generic name ,ulvopteris for a fragment of a pinna from the ,coal-,measures of ,dudweiler in ,germany bearing large pinnules1 which he compares with those of ,cardiopteris and species of ,rhacopteris4 ,the specimen appears to be indistinguishable from some of those already referred to as conforming to ,neuropteridium1 and it is difficult to recognise any reason for the creation of a new generic name4 ,we cannot hope to arrive at any satisfactory decision in regard to the precise affinity between ,neuropteridium validum and species referred to ,cardiopteris and other genera so long as portions of sterile fronds are the only tests at our disposal4 ,it is difficult to determine whether a specimen consisting of an axis bearing pinnules represents a large pinna of a bipinnate frond or if it is a complete pinnate leaf4 ,there is1 however1 no adequate reason for supposing that the presumably pinnate fronds from the ,gondwana ,land rocks are generically distinct from the ,lower ,carboniferous ,european species ,cardiopteris frondosa4 ,granting the probability that both genera are ,pteridosperms and closely allied to one another1 the two generic names may be retained on the ground of long usage and in default of satisfactory evidence confirmatory of generic identity4 ,cardiopteris would thus stand for a type of frond characteristic of the ,lower ,carboniferous strata of ,europe1 while ,neuropteridium is retained for the ,southern species ,n4 validum1 and for others from the ,trias of the ,vosges4 ,aphlebia4 ,this name was proposed by ,presl#achi for large leaf-like impressions having a pinnate or pinnatifid form and characterised by a confused irregular type of venation1 or by a fine superficial striation or wrinkling which simulates veins4 ,gutbier had previously described similar fossils as ,fucoides1 and other authors have described ,aphlebiae as species of ,rhacophyllum1 ,schizopteris1 and other genera#acij4 ,the term ,aphlebia is retained1 not as denoting a distinct genus but 7i7 as a descriptive name for detached leafy structures similar to those figured by ,presl1 which are now recognised as laminar appendages of the petioles of ferns or fern-like fronds1 and 7ii7 as an epithet for highly modified pinnules which frequently occur at the base of the primary pinnae of ,pecopteroid and ,sphenopteroid fronds 7e4g4 ,dactylotheca plumosa1 fig4 #bic7acia4 ,modified pinnules1 similar in their reduced and deeply dissected lamina to those represented in fig4 #bic1 are frequently found at the base of the primary pinnae of ,palaeozoic species of ,sphenopteris and other genera of ,pteridosperms or ferns1 including members of the ,coenopterideae4 ,potoni#acib gives a list of various types of ,aphlebiae in his paper on these organs4 ,a striking case has recently been described by ,zeiller in a ,french ,upper ,carboniferous species1 ,sphenopteris ,matheti#acic4 ,it would seem that the larger examples of ,aphlebiae are more frequently associated with the compound leaves of ,pteridosperms than with those of ,ferns#acid4 ,as examples of the larger types of ,aphlebiae reference may be made to ,aphlebia crispa 7,gutb47#acie1 which reaches a length of nearly #fj cm4 and has the form of a more or less triangular pinnate leaf divided into decurrent deeply lobed segments1 to a similar species represented by ,a4 ,germari 7 ,schizopteris lactuca ,germ47#acif which simulates the leaves of endive 7,cichorium endivia ,l471 and to some large forms figured by ,grand',eury#acig as species of ,schizopteris4 ,aphlebiae such as that figured by ,kidston#acih as ,rhacophyllum crispum1 with narrow ultimate segments1 might easily be mistaken for the impressions of an alga4 ,the term ,aphlebia may be applied also to the ,cyclopteroid pinnules on the petioles of some species of ,neuropteris1 ,odontopteris and ,archaeopteris4 ,goebel#acii has referred to the application by ,potoni and other authors of the term ,aphlebioid to the pinnules which serve as bud-protecting organs in recent fronds of ,gleichenia 7fig4 #bbf1 p4 #bij72 he expresses the opinion that it is superfluous and misleading to make use of a special designation for structures which are undoubtedly modified pinnules4 ,in the case of fossils it is1 however1 convenient to employ the term ,aphlebia as a descriptive name for modified pinnules or stipular structures which cannot be connected with definite species of fronds4 ,it is clear that some ,aphlebiod leaflets1 such as those of ,dactylotheca1 served as protective organs for the unexpanded pinnae#adjj1 and in all probability the large ,aphlebiae served the same purpose as the fleshy stipules of ,angiopteris and ,marattia which cover the uncoiled fronds4 ,the pinnatifid scale-leaves of considerable size 7fig4 #cea7 which occur in the leaf-axils or as ochrea-like stipules on the fronds of ,gunnera 7a tropical and subtropical ,dicotyledonous genus7 bear a very close resemblance to some ,palaeozoic ,aphlebiae1 e4g4 ,aphlebia crispa 7,gutb474 ,the recent and fossil scale-leaves may be regarded as similar in function as in form2 moreover the delicate coiled fronds of ,palaeozoic ,pteridosperms or ferns1 like those of some recent flowering plants1 may have been kept moist by a secretion of mucilage4 ,the pinnatifid stipules of ,marattia fraxinea 7fig4 #bda1 ,b1 p4 #cag7 resemble certain fossil ,aphlebiae1 and the wrinkled surface of the recent stipules presents an appearance similar to that which in some fossil forms has been erroneously described as veining4 ,it is not improbable that mantle-leaves of such recent ferns as ,polypodium quercifolium 7fig4 #bcd1 ,m1 p4 #cjc7 are comparable with some fossil ,aphlebiae which may have served as humus-collectors for ,palaeozoic epiphytes4 ,illustration3 ,,fig4 #cea4 ,scale-leaf of ,gunnera manicata4 7,slightly reduced4 ,m4,s47 ,the filiform appendages on the petioles of the recent fern ,hemitelia capensis 7fig4 #bce1 p4 #cjd7 have often been compared with the aphlebioid leaflets of fossil fronds4 ,potoni who has discussed the nature of ,aphlebiae regards them as vestiges of a once continuous lamina1 which formed a winged border to the branched axes of more primitive forms of fronds4 ,it is possible that the pinnules between the pinnae on the rachis of ,archaeopteris and the ,cyclopteroid leaflets of ,neuropteris and ,odontopteris may have the morphological significance attributed to them by ,potoni4 ,in some cases it is probable that the ,aphlebiae1 whether vestiges or not1 served the purpose of protecting either the whole frond or individual pinnae4 ,aphlebiae1 though especially characteristic of ,palaeozoic leaves1 are occasionally met with in the form of modified pinnules at the base of the primary pinnae on ,mesozoic ferns1 e4g4 in ,coniopteris hymenophylloides#adja4 ,in some fern fronds the lowest pinnule of each pinna differs in shape or size from the normal ultimate segments1 but it would be almost affectation to extend the use of the term ,aphlebia to such pinnules4 ,the ,jurassic species ,cladophlebis lobifolia 7,phill47 is a case in point#adjb4 ,in this fern1 which some authors speak of1 without sufficient reason1 as ,dicksonia lobifolia#adjc1 the lowest pinnule is large and different in shape from the others4 ,illustration3 ,,fig4 #ceb4 ,a4 ,sphenopteris obtusiloba4 ,pinnule4 7,enlarged4 ,after ,zeiller47 ,b1 ,c4 ,s4 obtusiloba4 7 nat4 size4 ,after ,zeiller47 ,d4 ,pecopteris arborescens4 7,slightly enlarged4 ,after ,zeiller47 ,e4 ,sphenopteris furcata 7 ,diplotmema furcatum74 7,slightly enlarged4 ,after ,zeiller47 ,sphenopteris4 ,sphenopteris is one of the many generic names which we owe to ,brongniart#adjd4 ,it is the generic designation used for a great number of ,palaeozoic and later fronds1 most of which are those of true ferns while some ,palaeozoic species are undoubted ,pteridosperms4 ,the genus1 which is purely provisional1 includes members of widely different families possessing pinnules of the same general type1 such as is represented in some recent species of ,davallia1 ,asplenium1 and other ferns4 ,the fronds of ,sphenopteris may be bipinnate1 tripinnate1 or quadripinnate2 the rachis may be dichotomously branched or the branching may be of the pinnate type characteristic of most recent ferns4 ,the pinnules are small2 they vary considerably in shape even in a single frond1 but the chief characteristics are3 the lobed lamina1 contracted and often wedge-shaped at the base 7fig4 #ceb71 the dichotomously branched veins radiating from the base or given off from a median rib at an acute angle4 ,the lamina may be divided into a few bluntly rounded lobes 7fig4 #ceb1 ,c7 or deeply dissected into linear or cuneate segments 7fig4 #ceb1 ,a1 ,b1 ,e74 ,examples of ,sphenopteroid leaves have already been described under the genera ,coniopteris1 ,onychiopsis1 ,ruffordia1 etc4 ,among the numerous examples of ,sphenopteris species from the ,carboniferous rocks mention may be made of ,sphenopteris obtusiloba ,brogn4#adje 7fig4 #ceb1 ,a-,c71 which occurs in the ,middle and ,lower ,coal-,measures of ,britain#adjf4 ,this type is characterised by the almost orbicular1 oval or triangular pinnules which may reach a length of #ae mm42 they are occasionally entire1 but more usually divided into #c to #e rounded lobes4 ,the forked veins radiate from the base of the pinnule4 ,the rachis may be dichotomously branched4 ,fructification unknown4 ,the species ,s4 furcata ,brongn4#adjg1 characteristic of the ,middle and ,lower ,coal-,measures of ,britain 7fig4 #ceb1 ,e71 is referred to under ,stur's genus ,diplotmema#adjh in which it is included by some authors solely because of the dichotomous habit of branching of the pinnae4 ,the pinna represented in fig4 #cec illustrates a similar type of pinnule4 ,this species1 which is very common in the ,calciferous ,sandstone of ,scotland1 was described by ,lindley and ,hutton as ,sphenopteris affinis#adji4 ,the fronds of ,sphenopteris affinis were discovered by ,mr ,peach#adaj in a fertile condition1 but he regarded the reproductive organs as those of a plant parasitic on the ,sphenopteris fronds4 ,kidston#adaa substituted ,stur's genus ,calymmatotheca for ,sphenopteris on the ground that the sporangia figured by ,peach under the name ,staphylopteris ,peachii bear a close resemblance to the organs which ,stur described as valves of an indusium in his species ,calymmatotheca ,stangeri#adab4 ,an examination of ,stur's specimens by ,miss ,benson#adac and by ,prof4 ,oliver and ,dr ,scott has confirmed ,stur's interpretation of the appendages at the tips of the fertile pinnae as valves of an indusial or cupular structure4 ,the superficially similar bodies on the fertile pinnae of ,s4 affinis are however true sporangia1 and cannot legitimately be included in the genus ,calymmatotheca as described by ,stur4 ,for this reason ,miss ,benson institutes a new genus ,telangium1 the type-species of which1 ,t4 ,scotti from the ,lower ,coal-,measures of ,lancashire1 is based on petrified material4 ,the ,scotch species ,sphenopteris affinis 7 ,calymmatotheca affinis of ,kidston7 is also transferred to ,telangium2 the sporangia are considered by ,miss ,benson to be microsporangia4 ,this with other species is no doubt correctly included in the ,pteridosperms4 ,a complete frond of ,sphenopteris affinis1 showing a regular dichotomy of the main axes1 is represented by an admirable drawing in ,hugh ,miller's ,testimony of the ,rocks#adad4 ,illustration3 ,,fig4 #cec4 ,sphenopteris affinis1 ,lind4 and ,hutt4 ,from the ,calciferous ,sandstone of ,burdiehouse 7,scotland74 7,sedgwick ,museum1 ,cambridge47 ,m4,s4 ,some of the ,palaeozoic species of ,sphenopteris probably represent the fronds of true ferns1 but others are known to have been borne by ,pteridosperms4 ,s4 ,hoeninghausi 7fig4 #bij1 ,c1 p4 #cii7 is the foliage of ,lyginodendron1 and ,scott#adae speaks of three species1 ,s4 dissecta1 ,s4 elegans1 and ,s4 ,linkii as the leaves of ,heterangium4 ,grand',eury#adaf has recorded the occurrence in ,french ,coal-,measures of seeds in association with other ,sphenopteroid fronds4 ,mariopteris1 ,diplotmema1 ,palmatopteris4 ,the discovery of sporangia on the fronds of several ,palaeozoic species of ,sphenopteris and ,pecopteris has led to the institution of new generic names1 which indicate an advance in knowledge beyond the stage implied by the use of those provisional designations based solely on the form and venation of the pinnules4 ,other names have been created by authors in place of ,sphenopteris and ,pecopteris on the ground that a striking feature in the mode of branching of fronds is sufficiently important to justify generic recognition even in the absence of fertile specimens4 ,as examples of designations based primarily on the branch-system of compound leaves1 the genera ,mariopteris1 ,diplotmema1 and ,palmatopteris may be briefly considered 7fig4 #ced ,a-,c74 ,dr ,kidston#adag is of opinion that the creation of new genera for purely vegetative characters of fronds is of no real advantage1 and he prefers to retain the older provisional names for species known only in the sterile condition4 ,on the other hand1 if we are sufficiently familiar with specimens large enough to enable us to recognise a well-defined morphological character1 it may serve a useful purpose to employ a generic designation for features which may have a phylogenetic value4 ,a comparative examination of ,palaeozoic1 ,mesozoic1 and recent compound fronds1 including both ,pteridosperms and true ferns1 brings to light certain distinguishing features characteristic of the older types which1 as ,potoni maintains#adah1 point to the derivation of the pinnate habit from a primitive dichotomous system of branching4 ,for a more complete discussion of this question reference should be made to ,potoni's suggestive papers4 ,among recent ferns ,matonia and ,dipteris1 two survivals from the past1 afford instances of fronds with a branching system of the dichotomous type4 ,similarly1 in ,gleichenia1 ,lygodium1 and more rarely in species of ,polypodiaceae 7e4g4 ,davallia aculeata1 fig4 #bcb7 dichotomy is a striking feature of the fronds4 ,in the great majority of recent ferns the fronds have assumed a pinnate habit4 ,among ,palaeozoic fern-like fronds dichotomous branching of the main rachis and of the pinnae is much more common4 ,potoni draws attention to several other features which distinguish ,palaeozoic fronds from the majority of later species3 the frequent occurrence of pinnules borne directly on the main rachis 7fig4 #ced1 ,d71 and of modified pinnules or ,aphlebiae on the rachis and petiole1 are characters to which he attributes an evolutionary significance4 ,the main point is that a comparative examination of leaf-form affords evidence in favour of the view that the modern type of frond1 with its naked rachis bearing two rows of pinnae1 has been derived from a less specialised type in which the distinction between the parts of the leaf is much less evident4 ,the primitive leaf was probably a dichotomously branched axis provided with a continuous lamina which eventually became broken up into separate lobes or pinnules4 ,as the dichotomy of the frond became less regular1 a pinnate habit was acquired1 as is clearly seen in many ,palaeozoic types which constitute connecting links between forked and pinnate fronds 7fig4 #ced1 ,d74 ,the ,aphlebiae may be remnants of the once-continuous lamina on the petiole1 and the normal pinnules borne on the rachis may be regarded as the attributes of fronds in which the division of physiological labour had not reached the stage which characterises the leaves of recent ferns4 ,mariopteris4 ,this name1 which is due to ,zeiller#adai1 is applied by him to ,palaeozoic fronds characterised by a double bifurcation of the rachis of the primary pinnae4 ,mariopteris muricata 7 ,pecopteris muricata ,schloth47 may be taken as the type of the genus4 ,this species is common in the ,lower and ,middle ,coal-,measures of ,britain and rare in the ,upper ,coal-,measures#adbj4 ,it is described by ,kidston#adba as one of the most polymorphic and widely distributed ,coal-,measure species4 ,the pinnules as seen in fig4 #cfd1 ,b1 are of the ,sphenopteroid type4 ,no fertile specimens are known1 but it is significant that ,grand',eury#adbb has recorded the association of ,mariopteris muricata and seeds4 ,the main rachis gives off alternate naked branches1 each of which bifurcates at its apex into two short naked axes1 and these are again forked1 the ultimate branches having the form of bipinnate pinnae provided with large ,sphenopteroid pinnules 7fig4 #ced1 ,b74 ,zeiller includes in ,mariopteris some species which ,stur#adbc referred to his genus ,diplotmema4 ,possibly some of the ,palaeozoic fronds with a zigzag rachis may have been climbers like ,lygodium4 ,illustration3 ,,fig4 #ced4 ,a4 ,palmatopteris4 ,b4 ,mariopteris4 7,a1 ,b1 after ,potoni47 ,c4 ,diplotmema ,zeilleri1 ,stur4 7,after ,zeiller47 ,c4 ,d4 ,zeilleri4 ,pinnule4 7 #c4 ,after ,zeiller47 ,d4 ,neuropteris macrophylla4 7,british ,museum47 ,d4 ,n4 macrophylla4 ,pinnule4 7,slightly enlarged4 ,after ,kidston47 ,e4 ,n4 heterophylla4 ,pinnule4 7,slightly enlarged4 ,after ,zeiller47 ,f4 ,n4 ,scheuchzeri4 7,slightly reduced4 ,after ,kidston47 ,g4 ,alloiopteris ,essinghii4 7,enlarged4 ,after ,potoni47 ,diplotmema4 ,this generic name is employed by ,zeiller#adbd and other authors in a more restricted sense than that in which it was originally used by ,stur4 ,the ,upper ,carboniferous species ,sphenopteris furcata ,brongn4 7fig4 #ceb1 ,e7 may serve as the type4 ,this species occurs in the ,middle and ,lower ,coal-,measures of ,britain#adbe4 ,the main rachis gives off branches as in ,mariopteris1 but in ,diplotmema each naked lateral branch is forked at its apex into two opposite pinnae bearing deeply dissected ,sphenopteroid pinnules4 ,zeiller#adbf and ,stur have recorded fertile specimens of ,diplotmema1 but in no case have actual sporangia been discovered4 ,in the species ,diplotmema ,zeilleri ,stur 7fig4 #ced1 ,c1 ,c7 two ,aphlebiae occur at the base of each secondary axis#adbg4 ,it has been pointed out by ,potoni that in ,diplotmema furcatum the equal dichotomy of the lateral branches is not characteristic of the frond as a whole4 ,in the case of branches higher on the rachis the dichotomy becomes unequal and the forked axis is gradually replaced by a simple pinna 7fig4 #ced1 ,a74 ,for this type of frond1 ,potoni proposed the generic name ,palmatopteris in place of ,diplotmema1 which he discards4 ,the long comparatively slender rachis of ,p4 furcata suggests comparison with the liane species of ,lygodium#adbh4 ,illustration3 ,,fig4 #cee4 ,a4 ,cephalotheca mirabilis1 ,nath4 ,fertile pinnae4 7,partially restored4 ,after ,nathorst47 ,b4 ,c4 mirabilis4 ,sterile pinnule4 ,nat4 size4 7,after ,nathorst47 ,cephalotheca4 ,this genus was proposed by ,nathorst#adbi for some peculiar bipinnate fertile fronds from the ,upper ,devonian rocks of ,bear ,island4 ,the pinnae bear slender forked ultimate segments represented by a few detached fragments 7fig4 #cee1 ,b71 associated with the rachises4 ,the fertile pinnae are given off in opposite pairs from the main axis over which they are concrescent 7fig4 #cee1 ,a74 ,a mop-like cluster of sporangia is borne on the lower surface and close to the base of a fertile pinna3 the exannulate sporangia are compared with those of ,scolecopteris4 ,nathorst compares ,cephalotheca with a ,belgian species of ,upper ,devonian age described by ,crpin#adcj as ,rhacophyton condrusorum and by ,gilkinet#adca as ,sphenopteris condrusorum4 ,a similar fossil is also described by ,baily#adcb as ,filicites lineatus from the ,kitorkan ,grits of ,ireland4 ,the position of ,cephalotheca cannot be definitely determined from the available data1 but it is more probable that it was a seed-bearing ,pteridosperm and not a true fern4 ,zeiller#adcc has recently expressed the same opinion4 ,thinnfeldia4 ,the genus ,thinnfeldia1 founded by ,ettingshausen in #ahebadcd on some ,hungarian ,liassic specimens1 though frequently included in the ,filicales1 cannot be said to occupy that position by virtue of any well-authenticated filicinean features4 ,it is by no means improbable that many of the species referred to this genus are closely allied to ,palaeozoic ,pteridosperms4 ,thinnfeldia may be briefly defined as follows3 ,fronds simple and pinnatifid1 pinnate or bipinnate3 rachis broad and occasionally dichotomously branched4 ,pinnules often fleshy or coriaceous2 broadly linear1 entire or lobed1 provided with a midrib from which simple or forked secondary veins are given off at an acute angle3 or the laminae may be short and broad without a midrib and traversed by several slightly divergent and forked veins4 ,no satisfactory evidence of reproductive organs has so far been adduced4 ,the genus is chiefly characteristic of ,upper ,triassic1 ,rhaetic1 and ,jurassic floras1 though it was in all probability represented in ,permian floras4 ,several species1 many of which are valueless1 are recorded also from ,cretaceous and ,tertiary formations4 ,search should be made for fertile specimens or for evidence as to the association of seeds with ,thinnfeldia fronds4 ,some ,permian fossils from ,kansas which ,sellards#adce has made the type of a new genus1 ,glenopteris1 appear to be indistinguishable generically from leaves of ,lower ,mesozoic age universally recognised as typical examples of ,thinnfeldia4 ,thinnfeldia odontopteroides 7,morris7#adcf4 ,figs4 #cef-ceh4 ,this is a very variable species as regards the shape and size of the ultimate segments and their venation4 ,it is a type of extended geographical range characteristic of ,rhaetic or ,upper ,triassic rocks in ,australia1 ,south ,africa1 ,india1 ,south ,america1 and various ,european localities4 ,frond bipinnate2 the broad rachis may be dichotomously branched4 ,pinnules with a thick lamina which may be almost semicircular in form1 deltoid1 broadly oval or broadly linear1 and often confluent at the base4 ,short and broad pinnules occur on some fronds directly attached to the main rachis between the pinnae4 ,the longer and narrower pinnules 7fig4 #cef1 ,c71 resembling those of the ,palaeozoic genus ,alethopteris1 have a well-defined midrib1 while the smaller segments are characterised by several slightly divergent veins which spring directly from the rachis 7fig4 #cef1 ,a74 ,epidermal cells polygonal or1 above the veins1 rectangular in shape2 stomata1 which are slightly sunk1 occur on both the upper and lower epidermis4 ,fertile specimens unknown4 ,the portion of a lobed pinnule shown in fig4 #cef1 ,b1 illustrates a form of segment intermediate between the linear type with a midrib and a row of shorter pinnules without a median vein4 ,fig4 #cef1 ,d1 represents another instance of variation in the arrangement of the veins in segments of different sizes4 ,various specific and generic names have been assigned to ,thinnfeldia fronds of ,rhaetic age on the ground of the occurrence of pinnules longer and narrower than those usually associated with ,t4 odontopteroides2 but in view of the range of variation met with in a single leaf it is advisable to extend rather than to restrict the boundary of what we are pleased to regard as a specific type4 ,illustration3 ,,fig4 #cef4 ,a-,d4 ,thinnfeldia odontopteroides 7,morris74 ,e4 ,ptilozamites4 7,e1 after ,nathorst47 ,the name ,thinnfeldia lancifolia has been applied by ,morris to fossils from ,australia which may be identified with ,t4 odontopteroides1 and the same designation is employed by ,szajnocha and by ,solms-,laubach#adcg for ,rhaetic specimens from ,south ,america4 ,similar fronds are described by ,geinitz#adch as ,thinnfeldia tenuinervis from ,argentine ,rhaetic strata4 ,odontopteris macrophylla ,curran1 ,t4 falcata ,ten4-,woods1 ,gleichenia lineata ,ten4-,woods1 and ,cardiopteris ,zuberi ,szaj4 afford other examples of what are probably closely allied forms#adci4 ,illustration3 ,,fig4 #ceg4 ,thinnfeldia odontopteroides 7,morris74 nat4 size4 ,some exceptionally large examples of ,t4 odontopteroides are figured by ,feistmantel#addj from the ,hawkesbury series of ,new ,south ,wales in which the bipinnate frond has a breadth of #be-cj cm4 ,a specimen from the ,molteno beds of ,south ,africa1 probably of ,rhaetic age1 represented in fig4 #ceg1 illustrates a smaller leaf with pinnules of the linear type1 some of which are partially divided into shorter pinnules with forked veins4 ,the example represented in fig4 #ceh1 from ,cyphergat 7,s4 ,africa71 shows two equal branches of a rachis with small contiguous segments4 ,illustration3 ,,fig4 #ceh4 ,thinnfeldia odontopteroides4 ,from a specimen in the ,british ,museum 7v4 #bdij74 #a nat4 size4 ,some specimens figured by ,zeiller#adda from the ,rhaetic strata of ,tonkin as ,pecopteris 7,bernouillia87 sp4 may be portions of ,thinnfeldia fronds1 and the large leaves which he refers to ,ctenopteris ,sarreni differ but slightly from the ,australian specimens described by ,feistmantel as ,t4 odontopteroides4 ,thinnfeldia rhomboidalis1 ,ettingshausen4 ,figs4 #cei1 #cfj1 ,c4 ,under this name ,ettingshausen described the type-specimen of the genus from ,lower ,lias strata at ,steierdorf in ,hungary4 ,he assigned the plant to the ,coniferae on the ground of a resemblance of the pinnules to the phylloclades of ,phyllocladus4 ,thinnfeldia rhomboidalis bears a close resemblance to ,t4 odontopteroides1 but the pinnules are usually longer and narrower1 as shown in the ,english specimen from the ,lower ,lias of ,dorsetshire represented in fig4 #cei4 ,the darker margin of the pinnules shown in fig4 #cfj1 ,c1 gives the impression of a revolute lamina1 but a microscopical examination points to a thicker cuticle at the edge of the segments4 ,illustration3 ,,fig4 #cei4 ,thinnfeldia rhomboidalis1 ,ettings4 ,slightly reduced4 ,from an ,english ,liassic specimen in the ,british ,museum4 ,m4,s4 ,the species is recorded from ,jurassic rocks of ,france1 ,germany1 ,italy1 ,india1 ,australia1 and elsewhere#addb4 ,palaeobotanical literature contains numerous records of ,jurassic1 ,cretaceous and some ,tertiary species referred to ,thinnfeldia1 but many of these are probably not generically identical with ,t4 odontopteroides or ,t4 rhomboidalis4 ,mr ,berry#addc in a paper on ,the ,american species referred to ,thinnfeldia concludes that the genus is 8a rather indefinite one 444 and badly in need of revision40 ,he regards the ,middle and ,upper ,cretaceous ,american species as ,conifers related to ,phyllocladus and probably forming a link between the ,podocarpeae and ,taxeae3 for these forms he proposes the generic name ,protophyllocladus4 ,the opinion has been expressed elsewhere#addd that this 8problematical#adde0 genus rests on an unsatisfactory basis2 the available data do not justify the use of a name which implies the existence in ,north ,american ,cretaceous floras of a type related to the ,new ,zealand and ,tasmanian ,conifer ,phyllocladus4 ,we are not in a position to assign a single species of ,thinnfeldia to the ,filicales or the ,gymnosperms4 ,a leaflet from ,jurassic rocks of ,poland figured by ,raciborski#addf shows what this author regards as the impression of a circular sorus3 no sporangia have been found4 ,a specimen in the ,british ,museum#addg1 which is said to come from ,rhaetic beds in ,queensland1 shows a row of contiguous polygonal prominences on each side of the midrib which resemble the sori of a fern2 but until sporangia are discovered we cannot determine the precise nature of this apparently fertile frond4 ,a species described by ,fontaine#addh from the ,potomac beds 7,wealden-,jurassic7 of ,north ,america as ,thinnfeldia variabilis affords a good example of a plant which cannot be identified with any degree of confidence either as a fern or a seed-bearing type4 ,mr ,berry draws attention to the former application of this name by ,velenovsk to a distinct ,lower ,cretaceous ,bohemian species and proposes for ,fontaine's plant the name ,t4 ,fontainei2 he maintains that no one has doubted the fern-nature of the ,potomac plant4 ,t4 variabilis may indeed be a fern1 but the evidence is not such as to preclude legitimate doubts as to the correctness of this suggestion4 ,solms-,laubach#addi1 in referring to ,schenk's view that ,thinnfeldia and its allies may represent a group intermediate between ,ferns and ,gymnosperms1 admits that it is a possible supposition2 he is1 however1 inclined to consider ,lomatopteris and ,cycadopteris1 8genera especially comparable with ,thinnfeldia0 as more probably ferns4 ,at this point we may conveniently consider a series of genera which occupy an equally uncertain position and bear a very close resemblance to ,thinnfeldia4 ,illustration3 ,,fig4 #cfj4 ,a4 ,lomatopteris jurensis4 7 nat4 size4 ,after ,kurr47 ,b4 ,l4 ,schimperi4 7 nat4 size4 ,after ,salfeld47 ,c4 ,thinnfeldia rhomboidalis1 ,ett4 7,slightly enlarged4 ,british ,museum4 ,no4 #ebfgb47 ,lomatopteris4 ,the generic name ,lomatopteris was proposed by ,schimper#adej for some bipinnate fronds originally described by ,kurr#adea from ,jurassic rocks of ,wrttemberg as ,odontopteris 787 jurensis 7fig4 #cfj1 ,a74 ,i have elsewhere expressed the opinion#adeb that this ,german species may be identical with ,thinnfeldia rhomboidalis ,ett4 ,kurr's type-specimen1 a portion of which is reproduced in fig4 #cfj1 ,a1 consists of a frond or large pinna characterised by a prominent and broad rachis giving off alternate linear pinnae bearing bluntly rounded1 contiguous and basally concrescent pinnules having a thick or revolute border and a central rib4 ,the lateral veins are visible in the ultimate segments of ,kurr's fossil4 ,saporta#adec has described several species1 which he refers to ,schimper's genus1 from ,french ,jurassic strata3 it is1 however1 difficult to recognise some of the examples represented in his illustrations as specifically distinct forms4 ,this author notices the resemblance of ,lomatopteris to ,thinnfeldia1 not only in habit but in the structure of the epidermal cells#aded4 ,in ,lomatopteris and in ,thinnfeldia the cells have straight and not sinuous walls and the slightly sunken stomata are surrounded by a ring of epidermal cells4 ,salfeld#adee has recently described portions of fronds from ,jurassic rocks of ,south-,west ,germany1 which he identifies as ,lomatopteris jurensis4 ,he disagrees with my view that ,lomatopteris does not differ sufficiently from ,thinnfeldia to be accorded generic autonomy1 chiefly on the ground that the folded-over edge of the pinnules is a distinguishing feature of ,lomatopteris4 ,there is1 however1 no difference1 in appearance at least1 between the leaflets of some species of ,thinnfeldia1 e4g4 ,t4 rhomboidalis from ,liassic rocks of ,england#adef1 and those referred to ,lomatopteris4 ,in a later paper1 ,salfeld#adeg describes some ,portlandian fragments from ,north ,germany as ,lomatopteris ,schimperi1 identifying them with a ,wealden fossil of somewhat doubtful affinity1 which ,schenk#adeh makes the type of his species4 ,the ,portlandian specimens are described as tripinnate1 with thick decurrent obtusely terminated pinnules with a revolute edge4 ,the general form of the frond is very similar to that of ,l4 jurensis4 ,salfeld publishes a photograph of a large specimen which he describes as fertile and a drawing of a piece of a pinna3 the latter is reproduced in fig4 #cfj1 ,b4 ,he speaks of sori occurring in two rows1 probably attached to lateral veins1 in the groove between the midrib and the revolute edge of the lamina4 ,the sporangia are described as 8nicht nher bekannt#adei40 ,an examination of the figures reveals nothing as to the nature of the 8sori40 ,the specimens are considered by ,salfeld to afford decisive evidence against the view that ,lomatopteris and ,thinnfeldia are generically identical4 ,nothing has so far been published which constitutes a valid argument in favour of retaining ,schimper's generic name4 ,cycadopteris4 ,zigno#adfj founded the genus ,cycadopteris on ,italian ,jurassic impressions regarded by ,schimper as indistinguishable from ,lomatopteris4 ,as ,solms-,laubach#adfa points out1 the supposed sori of ,cycadopteris described by ,zigno are not convincing4 ,there appear to be no satisfactory reasons for separating ,cycadopteris from ,lomatopteris1 nor do the fronds described under these names exhibit any important differences from ,thinnfeldia4 ,ptilozamites4 ,nathorst#adfb founded this genus on a remarkable series of specimens from the ,rhaetic ,coal-beds of ,scania and assigned it to the ,cycadophyta4 ,the species ,ptilozamites ,heeri may be taken as a representative type4 ,the leaves are linear and simply pinnate4 ,in the example shown on a much reduced scale in fig4 #cfa the frond is #ec cm4 long and #ba cm4 broad4 ,the upper edge of each pinnule is straight or slightly concave2 the lower edge is rounded2 the veins are slightly divergent and dichotomously branched 7fig4 #cef1 ,e1 p4 #eci74 ,in some of ,nathorst's specimens the broad rachis is forked as in many ,thinnfeldias4 ,as a comparison of fig4 #cef1 ,a and ,e1 shows1 the pinnules of some specimens of ,thinnfeldia odontopteroides are identical with those of ,ptilozamites4 ,in the latter genus the rachis is either unbranched or occasionally forked1 while in ,thinnfeldia the branching may be of the dichotomous or pinnate type4 ,in ,ptilozamites the segments appear to be always without a midrib1 while a median vein frequently occurs in those of ,thinnfeldia4 ,there can be little doubt as to the very close alliance between the ,rhaetic species referred to these two genera4 ,the name ,ptilozamites should perhaps be retained for such long and narrow fronds as that shown in fig4 #cfa3 no species included in ,thinnfeldia is known in which the rachis reached so great a length without branching4 ,the habit of ,ptilozamites ,heeri predisposes one in favour of ,nathorst's opinion that the fronds are ,cycadean3 we have no information in regard to the nature of the reproductive organs4 ,illustration3 ,,fig4 #cfa4 ,ptilozamites ,heeri1 ,nath4 7 nat4 size4 ,after ,nathorst47 ,ctenopteris4 ,this name was instituted by ,saporta#adfc1 at ,brongniart's suggestion1 for ,liassic species characterised by pinnules like those of ,thinnfeldia1 but distinguished by the bipinnate habit of the frond4 ,saporta compares the genus with the ,palaeozoic leaves known as ,odontopteris1 and with ,italian ,jurassic plants referred by ,zigno to his genus ,dichopteris4 ,the name ,ctenozamites is applied by ,nathorst#adfd to the type of frond which ,saporta1 ,zeiller1 and other authors refer to ,ctenopteris4 ,nathorst instituted ,ctenozamites for fossils agreeing in the form and venation of the pinnules with his genus ,ptilizamites but differing in being bipinnate and not pinnate4 ,fronds of ,ctenopteris are characteristic of the ,jurassic and ,rhaetic series2 they are known only in the sterile condition4 ,as ,zeiller#adfe says1 ,ctenopteris may be a member of the ,cycadofilices1 an extinct group founded on ,palaeozoic plants combining ,cycadean and ,filicinean characters1 and some of which are now known to be ,pteridosperms4 ,it is probable that the genus is not a true fern3 it is more likely to be a member of the ,cycadophyta or of some generalised extinct group4 ,ctenopteris cycadea 7,brongniart74 ,fig4 #cfb4 #ahbh4 ,filicites cycadea1 ,brongniart1 ,hist4 ,vg4 foss4 p4 #chg1 ,pl4 ,,cxxix4 #ahcb4 ,odontopteris cycadea1 ,berger1 ,verstein4 ,coburg ,geg4 p4 #bc1 ,pl4 ,,iii4 #ahgc4 ,ctenopteris cycadea1 ,saporta1 ,pal4 ,fran4 ,vol4 ,i4 p4 #cee1 ,pls4 ,,xl4 ,,xli4 ,frond bipinnate1 broad rachis giving off branches at an acute angle2 pinnules broadly linear1 slightly falcate1 with several slightly divergent forked veins4 ,a frond very similar to the ,lower ,lias specimen from ,dorsetshire represented in fig4 #cfb was described by ,leckenby as ,ctenis ,leckenbyi 7,bean ,,ms47 from the ,inferior ,oolite of ,yorkshire#adff4 ,leckenby recognised the possibility of a ,cycadean affinity1 but regarded the bipinnate habit as an objection4 ,the branched fronds of the ,australian ,cycad ,bowenia supply an answer to this objection4 ,several good examples of ,ctenopteris cycadea are figured by ,schenk#adfg from ,rhaetic rocks of ,persia4 ,zeiller's ,tonkin ,rhaetic species1 ,c4 ,sarrani#adfh1 affords a striking illustration of the difficulty of drawing a clear line of separation between ,ctenopteris and some species of ,thinnfeldia4 ,illustration3 ,,fig4 #cfb4 ,ctenopteris cycadea1 ,brongn4 7 nat4 size47 ,from a specimen in the ,british ,museum4 ,m4,s4 ,ctenopteris is in all probability very closely related to ,thinnfeldia and ,ptilozamites4 ,dichopteris4 ,this genus was proposed by ,zigno#adfi for some large specimens from the ,jurassic plant-beds of ,northern ,italy4 ,the bipinnate leaves are characterised by the great breadth of the rachis which is dichotomously branched in the distal region 7fig4 #cfc72 the linear pinnae reach a considerable length4 ,pinnules relatively small1 oblong and slightly contracted at the base2 the decurrent and confluent lamina forms a narrow wing to the main axis4 ,veins slightly divergent and forked1 as in ,ptilozamites4 ,dichopteris visianica1 ,zigno4 ,fig4 #cfc4 ,a specimen of this species in the ,padua ,museum has a total length of #hc cm4 ,it has been elsewhere suggested#adgj that a fragment figured by ,zigno as a fertile example of this type is probably part of a frond of the ,osmundaceous fern ,todites4 ,since this opinion was expressed ,i have had an opportunity of examining the actual specimen at ,padua3 the circular patches described by ,zigno as sori appear to be irregularities in the matrix and not an original feature4 ,brongniart#adga instituted the genus ,pachypteris for some imperfectly preserved ,english ,jurassic fossils from ,whitby1 which he described as ,p4 lanceolata4 ,specimens have since been described#adgb from the ,inferior ,oolite rocks of the ,yorkshire coast4 ,brongniart described the pinnules as being without veins or as possessing only a midrib4 ,it is almost certain that the apparent absence of veins in most specimens#adgc is due to the fleshy nature of the segments and that the species ,p4 lanceolata should be transferred to ,dichopteris4 ,krasser#adgd has described a species from ,cretaceous rocks of the island of ,lesina1 off the ,dalmatian coast1 as ,pachypteris dalmatica which is very similar in habit to the ,english specimens and to ,zigno's ,dichopteris visianica4 ,one of ,krasser's specimens is practically identical with ,dichopteris lanceolata 7,brongn471 while in others the small pinnules are replaced in some of the pinnae by a continuous lamina with a few distal serrations4 ,the latter form a link between the ,dichopteris and ,thinnfeldia type of segment4 ,krasser gives a full rsum of opinions expressed by other authors in regard to the position of ,pachypteris 7 ,dichopteris7 and decides in favour of a ,cycadean alliance4 ,illustration3 ,,fig4 #cfc4 ,dichopteris visianica1 ,zigno4 7 nat4 size4 ,after ,zigno47 ,a ,french ,jurassic plant which ,saporta#adge made the type of a new genus ,scleropteris1 and described as ,s4 ,pomelii1 appears to be indistinguishable from ,dichopteris4 ,dichopteris1 though conveniently retained as a distinct genus1 agrees so closely1 in the broad and forked rachis and in the fleshy pinnules1 with ,thinnfeldia that it would seem reasonable to regard the two genera as members of the same group4 ,several authors have drawn attention to the striking resemblance in form and venation between the fronds of the ,palaeozoic genus ,odontopteris and those of ,ctenopteris and ,thinnfeldia4 ,in ,odontopteris1 as in ,neuropteris1 another ,palaeozoic genus1 the rachis occasionally bifurcates as in ,thinnfeldia and ,dichopteris1 and the ultimate segments of some species of ,odontopteris 7fig4 #cff1 ,a7 are practically identical with those of ,thinnfeldia and ,ptilozamites4 ,odontopteris is probably a ,pteridosperm4 ,there is no adequate reason for supposing that this group of plants which played a prominent part in the ,permo-,carboniferous floras was no longer in existence during the ,mesozoic era4 ,odontopteris4 ,brongniart#adgf instituted the genus ,odontopteris for compound fronds from the ,coal-,measures characterised by pinnules attached by the whole breadth of the base and traversed by numerous forked veins4 ,odontopteris is very rare in ,british ,carboniferous rocks and 8appears to be restricted to the ,middle and ,upper ,coal-,measures#adgg40 ,illustration3 ,,fig4 #cfd4 ,a4 ,alethopteris lonchitica 7,schloth474 nat4 size4 ,b4 ,mariopteris muricata 7,schloth474 #b4 ,c4 ,odontopteris cf4 alpina 7,presl74 nat4 size4 ,d4 ,o4 cf4 alpina4 ,portion of pinna enlarged4 7,a-,d4 ,from photographs by ,dr ,kidston47 ,fronds large1 bipinnate or tripinnate1 the main rachis1 which may be dichotomously branched1 bears long linear pinnae with broadly linear or deltoid pinnules1 acute or blunt1 attached by the whole of the base2 the lower margin of the lamina1 which is usually entire and rarely lobed 7e4g4 ,odontopteris osmundaeformis7#adgh1 is often decurrent on the axis of the pinna4 ,the basal pinnule of each pinna is frequently attached by a contracted base1 and the lamina may differ in form from that of the normal segments4 ,pinnules often occur on the main rachis1 and in some species the petiole bears modified pinnules which are larger than the ultimate segments of the pinnae and in some cases ,cyclopteroid in shape4 ,the pinnules are traversed by numerous dichotomously branched veins2 if a midrib is present it dies out in the basal part of the lamina4 ,in some species 7genus ,mixoneura7 pinnules of the ,neuropteroid type1 characterised by a well-defined midrib1 occur in association with typical ,odontopteroid pinnules on the same pinna4 ,illustration3 ,,fig4 #cfe4 ,odontopteris minor1 ,brongn4 7,rather less than nat4 size4 ,after ,zeiller47 ,the pinnules are omitted in the right-hand branch4 ,the species represented in fig4 #cfd1 ,c1 ,d1 from the ,middle ,coal-,measures of ,barnsley1 ,yorkshire1 illustrates the form and venation of the ,odontopteris type of pinnule4 ,another species1 ,o4 ,reichiana ,gutb4#adgi1 is also recorded by ,kidston from the ,lower ,coal-,measures of ,lancashire4 ,some unusually good specimens of the type-species of the genus ,odontopteris minor1 ,brongn41 have been figured by ,zeiller#adhj from the ,coal-,measures of ,blanzy 7fig4 #cfe7 which show the dichotomy of the main axis and the occurrence of ,aphlebiae on the petiole4 ,the late ,dr ,weiss#adha divided ,odontopteris into two sections1 ,xenopteris and ,mixoneura1 the pinnules of the former having the form shown in fig4 #cfd1 ,d2 while in species of the latter sub-genus some of the pinnules are identical in form and venation with those of ,neuropteris except that they are attached by the whole breadth of the base4 ,zeiller#adhb employs ,mixoneura as a generic designation4 ,in an ,american species ,o4 ,wortheni ,lesq4#adhc the pinnules bear numerous hairs like those on some species of ,neuropteris 7fig4 #cgc1 p4 #egj74 ,the large size of the fronds of ,odontopteris suggested to ,weiss#adhd that they were borne on the stems of tree-ferns1 but ,grand',eury's#adhe examination of specimens in the ,coal-beds of central ,france led him to picture the plant as bearing a tuft of leaves on a short subterranean stem4 ,renault and ,zeiller#adhf1 on the other hand1 obtained evidence in the ,commentry ,coal-field of fronds borne on elongated stems which grew on the ground and were supported by stronger plants4 ,stur#adhg was the first to suggest that ,odontopteris should be excluded from the ferns4 ,grand',eury's#adhh supposed fertile pinnules of ,odontopteris do not afford any satisfactory evidence of the sporangial nature of the small swellings which he figures at the ends of the veins4 ,this author pointed out several years ago that the petioles of some species of ,odontopteris possess the anatomical features of ,myeloxylon1 a type of leaf-stalk which is now known to belong to ,pteridosperms4 ,in a recent paper ,grand',eury#adhi records the association of ,odontopteris fronds with small seeds 7,odontopterocarpus71 a discovery which leaves little or no doubt as to the ,pteridospermic nature of the genus4 ,the fronds of ,odontopteris are very similar in habit to those of ,neuropteris1 another ,pteridospermic genus4 ,the similarity between some ,odontopteris and ,thinnfeldia leaves1 to which attention has already been called1 is well illustrated by ,o4 genuina ,grand',eury#adij1 a pinnule of which is represented in fig4 #cff1 ,a4 ,odontopteris is a fairly widespread genus in ,upper ,carboniferous and ,lower ,permian rocks1 and is recorded also from ,triassic strata3 it is represented in the ,coal-fields of ,north ,america and in several parts of ,europe#adia4 ,in some fronds included in ,odontopteris the pinnae are characterised by a broad irregularly lobed lamina which also forms a winged border to the rachis4 ,examples of this form are afforded by ,odontopteris ,browni ,sew4#adib from the ,burghersdorp ,series 7,triassic87 of ,cape ,colony1 and ,o4 ,fischeri described by ,brongniart#adic from the ,permian of ,russia4 ,the ,russian species would perhaps be more appropriately placed in the genus ,callipteris1 as ,weiss#adid suggests2 the absence of venation in ,o4 ,browni renders generic identification unsatisfactory4 ,illustration3 ,,fig4 #cff4 ,a4 ,odontopteris genuina 7,grand',eury74 7 #b4 ,after ,renault and ,zeiller47 ,b4 ,callipteridium gigas 7,gutb474 7 #b4 ,after ,zeiller47 ,c4 ,callipteris ,pellati 7,zeill474 7 #a4 ,after ,zeiller47 ,d4 ,c4 lyratifolia 7,goepp474 7 #a4 ,after ,zeiller47 ,callipteris4 ,brongniart#adie instituted this genus for certain species of supposed ferns previously referred to the genera ,pecopteris1 ,alethopteris1 and ,neuropteris4 ,callipteris is a characteristic ,permian plant which is almost certainly a ,pteridosperm4 ,zeiller has pointed out that such descriptions of fertile specimens as have been written are unsatisfactory4 ,a few years ago1 however1 ,grand',eury#adif recorded the occurrence of seeds in association with ,callipteris fronds in the ,autun district1 and in some cases they were found attached to the pinnae and rachis4 ,the seeds are ovoid or spherical 7#e-aj mm4 broad7 and smaller than those of ,neuropteris4 ,the drawings of fertile segments published by ,weiss#adig afford no indication of reproductive organs4 ,potoni#adih figures some pinnules of ,callipteris conferta in which the thick lamina is covered with sinuous grooves probably made by some insect larvae3 as he suggests1 similar markings may have been mistaken for the remains of sori4 ,the occurrence of ,callipteris fronds recorded by ,weber and ,sterzel#adii in association with ,medullosa stems in the ,lower ,permian of ,saxony is in accordance with ,grand',eury's conclusion4 ,fronds reaching #a metre in length1 bipinnate or tripinnate1 main rachis frequently exhibiting a combination of dichotomous and pinnate branching4 ,pinnae linear1 usually crowded1 decurrent on the rachis2 the pinnules on the lower side of the pinnae are continued on to the rachis4 ,pinnules of the ,pecopteroid type1 entire or slightly lobed1 or of the ,sphenopteroid type and more or less deeply dissected 7fig4 #cff ,c1 ,d71 the lamina of adjacent pinnules concrescent2 on the lower pinnae the lamina may be continuous as in an ,alethopteris pinnule4 ,a midrib may extend almost to the bluntly rounded apex of the ultimate segments1 giving off oblique1 simple1 or forked veins1 the lowest of which arise directly from the rachis2 in the ,sphenopteroid forms the lateral veins are given off at a more acute angle4 ,a striking feature of the genus is the occurrence of pinnules on the main rachis1 as in ,odontopteris4 ,zeiller has wisely extended the application of ,callipteris to fronds possessing this character irrespective of the entire or lobed form of the ultimate segments4 ,he found among the numerous examples of the genus obtained from ,autun#aejj and ,lodve#aeja transitional forms connecting such species as ,c4 conferta 7fig4 #cfg7 and ,c4 ,pellati ,zeill4 7fig4 #cff1 ,c7 in which the ,pecopteroid pinnules are slightly lobed1 with ,c4 lyratifolia 7,goepp47 7fig4 #cff1 ,d71 ,c4 flabellifera#aejb 7,weiss71 and ,c4 ,bergeroni ,zeill4 characterised by deeply lobed ,sphenopteroid segments4 ,callipteris conferta 7,sternberg7#aejc4 ,fig4 #cfg4 #agbc4 ,scheuchzer1 ,herb4 ,diluv4 ,pl4 ,,ii41 fig4 #c4 #ahbf4 ,neuropteris conferta1 ,sternberg1 ,flor4 ,vorwelt1 p4 #ag4 #ahdi4 ,callipteris conferta1 ,brongniart1 ,tableau1 p4 #bd4 ,this polymorphic species 7fig4 #cfg7 is one of the most characteristic ,permian plants4 ,the oval-linear pinnules1 attached by the whole base1 occur on both pinnae and rachis2 this feature1 the thick texture of the lamina1 and the linear1 obliquely set1 pinnae render the fronds easily recognisable4 ,the fronds bore seeds4 ,illustration3 ,,fig4 #cfg4 ,callipteris conferta4 ,from the ,permian of ,aschbach1 ,rhenish ,prussia 7,british ,museum1 ,no4 #cijeb74 ,in a recent account of some ,permian plants from ,germany1 ,schuster#aejd refers a portion of a frond to ,callipteris conferta 7,sternberg7 var4 polymorpha ,sterzel1 which is characterised by unusually large and polymorphic pinnules4 ,in size and shape the pinnules recall those of ,neuropteridium validum ,feist4 ,callipteridium4 ,the name ,callipteridium1 created by ,weiss#aeje as a sub-genus of ,odontopteris1 is applied by ,zeiller and other authors to a few ,upper ,carboniferous and ,permian species characterised by the occurrence of simply pinnate pinnae on the main rachis between the bipinnate primary pinnae4 ,single pinnules are borne directly on the rachis of the primary pinnae between the pinnate branches4 ,the form and venation of a typical pinnule are shown in fig4 #cff1 ,b4 ,callipteridium pteridium1 originally recorded by ,schlotheim as ,filicites pteridius#aejf1 has been fully described by ,renault and ,zeiller from unusually large specimens found in the ,commentry ,coal-field#aejg4 ,this species illustrates the peculiar morphological features of the genus4 ,the main rachis of the tripinnate fronds1 several metres long1 shows a combination of dichotomous and pinnate branching2 from the zigzag and forked axis are given off bipinnate pinnae and1 between these1 shorter pinnate branches4 ,the pinnules closely resemble those of ,callipteris conferta but reach a greater length2 the pinnules borne on the rachises of the lateral branches differ from the others in their broader base and more triangular lamina4 ,no fertile specimens have been found4 ,it is probable that ,callipteridium was not a true fern1 and that ,white#aejh is correct in including it among the ,pteridosperms4 ,archaeopteris4 ,in #aheb ,forbes#aeji published a brief description of some supposed fern fronds1 found by the ,geological ,surveyors of ,ireland in ,upper ,devonian rocks of ,kilkenny1 under the name ,cyclopteris hibernica4 ,the ,irish specimens were more fully described by ,baily#aeaj in #aheh4 ,fronds of the same type were referred by other authors to ,cyclopteris1 ,adiantites or ,noeggerathia1 until ,schimper#aeaa proposed the generic name ,palaeopteris on the ground that the fronds described by ,forbes and ,baily are distinguished by the nature of their fertile pinnae from the sterile leaves included in ,brongniart's provisional genus ,cyclopteris4 ,the earlier use of ,palaeopteris by ,geinitz for an entirely different plant led ,dawson#aeab to institute the genus ,archaeopteris4 ,the genus ,archaeopteris may be defined as follows3 ,fronds bipinnate1 reaching a considerable length 7#ij cm472 the stout rachis bears long linear pinnae2 sterile pinnules obovate or cuneate with an entire1 lobed1 fimbriate1 or laciniate lamina traversed by divergent dichotomously branched veins4 ,the fertile pinnae usually occur on the lower part of the rachis2 pinnules with a much reduced lamina bear numerous fusiform or oval exannulate sporangia 7fig4 #cfi1 ,a1 ,e1 ,h71 sessile or shortly stalked1 singly1 or in groups of two or three4 ,the base of the petiole is characterised by a pair of partially adnate stipules 7fig4 #cfi1 ,c1 ,d71 and single pinnules or scales occur in some species on the rachis between the pinnae and on the petiole4 ,illustration3 ,,fig4 #cfh4 ,archaeopteris hibernica4 7,from a specimen in the ,science and ,art ,museum1 ,dublin4 ,rather less than nat4 size47 ,archaeopteris hibernica 7,forbes74 ,figs4 #cfh1 #cfi1 ,a-,c4 ,the specimen from ,kilkenny represented in fig4 #cfh has a length of over #hj cm4 ,the upper pinnae bear numerous imbricate obovate pinnules 7fig4 #cfi1 ,a1 ,b7 with an entire or very slightly fimbriate margin1 while on the shorter lower pinnae the ultimate segments are reduced to a slender axis bearing numerous fusiform sporangia1 #b-c mm4 in length4 ,kidston#aeac has pointed out that sporangia occasionally occur on the edge of ordinary pinnules1 and he first recognised the stipular nature of the scale-like appendages which ,baily noticed on the swollen petiole base 7#e cm4 broad7 of the ,irish species 7fig4 #cfi1 ,c74 ,restorations of ,archaeopteris hibernica have been figured by ,baily#aead and by ,carruthers#aeae1 but the description of the fertile pinnae by the latter author requires modification in the light of ,kidston's description of the ,dublin specimens4 ,archaeopteris is recorded from ,upper ,devonian rocks of the ,south of ,ireland1 ,belgium1 ,germany1 ,southern ,russia1 ,bear ,island1 and ,ellesmere ,land in the ,arctic regions1 ,canada1 ,pennsylvania1 and elsewhere4 ,many of the specimens described under different names bear a close resemblance1 which in some cases probably amounts to specific identity1 to ,a4 hibernica4 ,a4 ,jacksoni originally described by ,dawson#aeaf and more recently by ,smith and ,white#aeag from ,devonian rocks of ,maine1 the ,canadian type ,a4 gaspiensis ,daws41 and some species figured by ,lesquereux#aeah from ,pennsylvania1 are examples of forms which present a striking similarity in habit to the ,irish species4 ,the ,belgian ,devonian fossils named by ,crpin#aeai ,palaeopteris hibernica var4 minor are regarded by him as probably identical with ,goeppert's species ,cyclopteris ,roemeriana from the neighbourhood of ,aachen4 ,heer recorded ,archaeopteris ,roemeriana from ,upper ,devonian beds in ,bear ,island1 and ,nathorst#aebj1 who has published a more complete account of the ,arctic forms1 draws attention to the resemblance of some of them to ,a4 hibernica4 ,a species described by ,schmalhausen#aeba from the ,upper ,devonian of ,southern ,russia as ,a4 archetypus 7fig4 #cfi1 ,d7 appears to differ from ,a4 hibernica in the slightly less reduced lamina of the fertile segments4 ,this species has been more adequately illustrated by ,nathorst#aebb from material collected in ,ellesmere ,land3 he is unable to confirm ,schmalhausen's statement that the pinnae are spirally disposed4 ,the species ,a4 fimbriata 7fig4 #cfi1 ,g7 described by ,nathorst from ,bear ,island is characterised by the more deeply dissected lamina of the sterile pinnules4 ,in ,a4 fissilis ,schmal4 from ,russia and ,ellesmere ,land the lamina 7fig4 #cfi1 ,e1 ,f7 is cut up into filiform segments3 a fertile pinnule of this species is represented in fig4 #cfi1 ,e4 ,some sterile impressions figured by ,krasser#aebc from ,palaeozoic strata 7,lower ,carboniferous or ,upper ,devonian87 in the province of ,nanshan in ,china as ,noeggerathia acuminifissa are considered by ,zeiller#aebd to be portions of an ,archaeopteris or ,rhacopteris frond4 ,the resemblance to the former genus is however by no means close enough to warrant a reference to ,archaeopteris4 ,the sterile specimens described by ,stur#aebe from the ,culm of ,altendorf as species of ,archaeopteris are probably not generically identical with the ,irish and ,arctic species4 ,the dichotomous branching of the rachis in ,a4 ,tschermaki and ,a4 ,dawsoni is a feature unknown in ,archaeopteris4 ,in the absence of fertile pinnae the separation of ,archaeopteris from ,rhacopteris is by no means easy4 ,illustration3 ,,fig4 #cfi4 ,a4 ,archaeopteris hibernica4 ,fertile pinna4 ,dublin ,geological ,survey ,museum4 7,reduced4 ,after ,kidston47 ,b4 ,a4 hibernica4 ,pinnule4 7,slightly enlarged4 ,after ,carruthers47 ,c4 ,a4 hibernica4 ,base of petiole4 7,dublin ,museum4 ,after ,kidston47 ,d4 ,a4 archetypus4 ,base of petiole3 ,ellesmere ,land4 7,after ,nathorst4 nat4 size47 ,e4 ,a4 fissilis4 ,sporangia4 7,slightly enlarged4 ,after ,schmalhausen47 ,f4 ,a4 fissilis4 ,sterile pinnule4 ,ellesmere ,land4 7,slightly enlarged4 ,after ,nathorst47 ,g4 ,a4 fimbriata4 ,bear ,island4 7,after ,nathorst4 nat4 size47 ,h4 ,archaeopteris sp4 ,ellesmere ,land4 7,after ,nathorst4 nat4 size47 ,archaeopteris was regarded by ,carruthers as a fern closely allied to recent species of ,hymenophyllaceae1 but this conclusion was based upon an interpretation of the fertile segments which ,kidston#aebf has shown to be incorrect4 ,the latter author regarded the presence of stipules and the structure of the exannulate sporangia as evidence of a ,marattiaceous alliance4 ,in a later reference to ,archaeopteris1 ,kidston expresses the opinion that the genus is not a true fern but a member of the ,cycadofilices or ,pteridosperms1 a view shared by ,grand',eury#aebg and doubtless by many other palaeobotanists4 ,the sporangia of ,archaeopteris appear to be of the same type as those of ,dactylotheca 7fig4 #bij1 ,e1 p4 #cii74 ,schmalhausen gave expression to his disagreement with ,nathorst and other authors who referred ,archaeopteris to the ,marattiaceae by proposing the distinctive group-name ,archaeopterideae4 ,there can be little doubt that the reproductive organs of ,archaeopteris so far discovered are microsporangia1 and that the plant bore seeds4 ,the sporangia are larger than those of any known fern and1 as ,kidston points out1 they are similar to those of ,crossotheca which he has shown to be microsporangia of the ,pteridosperm ,lyginodendron4 ,the presence of stipules in ,archaeopteris hibernica1 ,a4 fimbriata1 ,a4 archetypus 7fig4 #cfi1 ,d7 and probably throughout the genus does not materially affect the question of taxonomic position4 ,stipules are a characteristic feature of ,marattiaceae and1 in a reduced form1 of ,osmundaceae1 but similar appendages are borne at the base of the petiole of the ,cycad ,ceratozamia4 ,the occurrence of ,aphlebiae on the rachis of ,archaeopteris is a feature shared by the fronds of ,neuropteris and other ,pteridosperms4 ,neuropteris4 ,the fronds for which ,brongniart#aebh created this genus1 though suspected by ,stur in #ahhc as wrongly classed among the ferns1 have only recently been shown to be the leaves of ,pteridosperms4 ,as yet only one case is recorded in which ,neuropteris pinnae occur in organic connexion with seeds#aebi1 but it is almost certain that the genus as a whole must be placed in this generalised group4 ,renault#aecj pointed out that the petioles of ,neuropteris fronds from ,autun had the anatomical features of ,myeloxylon 7petiole of ,medullosa74 ,since ,kidston's important discovery of seed-bearing pinnae of ,n4 heterophylla1 ,grand',eury#aeca has recorded the association of ,neuropteris fronds with seeds in ,french ,coal-fields4 ,by some of the older authors ,neuropteris was compared with ,osmunda because of a similarity in venation4 ,in the frequent dichotomy of the frond and in the occurrence of pinnules on the rachis1 ,neuropteris closely resembles ,odontopteris#aecb3 there can be little doubt as to the close relationship of the ,pteridosperms possessing these two types of foliage4 ,neuropteris may be defined as follows3 ,fronds reaching a considerable size1 probably in soma cases a length of #aj metres#aecc2 bi- or tri-pinnate2 the rachis may be dichotomously branched 7figs4 #ced1 ,d2 #cgj72 both rachis and petiole bear single pinnules1 those on the latter frequently differ from the normal leaflets in their larger ,cyclopteroid laminae 7fig4 #cgj74 ,pinnules entire1 rarely slightly lobed1 broadly linear1 attached by a small portion of the base1 which is usually more or less cordate4 ,in ,n4 ,grangeri ,brongn4 the pinnules are attached by a short pedicel#aecd4 ,the midrib always dies out before reaching the blunt or pointed apex of the lamina and gives off at an acute angle numerous secondary veins characterised by their arched course and repeated forking4 ,illustration3 ,,fig4 #cgj4 ,neuropteris frond with ,cyclopteris leaflets4 ,english ,coal-,measures4 7,from a block given to me by ,mr ,carruthers4 ,a4,c4,s47 ,potoni describes the secondary veins of the pinnules of ,neuropteris pseudogigantea#aece as occasionally anastomosing1 a feature which may be regarded as a step towards the reticulate venation of the closely allied genus ,linopteris4 ,renault#aecf described some petrified pinnules of ,neuropteris in which the mesophyll shows a differentiation into upper palisade tissue and lacunar tissue below2 the lower epidermis is infolded at intervals where grooves 7probably stomatal7 occur like those on the leaves of an ,oleander 7,nerium oleander74 ,the rachises of ,neuropteris fronds are described by ,grand',eury under the generic name ,aulacopteris#aecg4 ,neuropteris heterophylla1 ,brongniart#aech4 ,figs4 #ced1 ,e2 #cga4 ,this species is characteristic of the ,lower ,coal-,measures of ,britain2 it occurs also in the ,middle ,coal-,measures and is a common type in ,upper ,carboniferous rocks in various parts of the world4 ,the fronds are large and tripinnate1 the rachis is often dichotomously branched and ,cyclopteroid pinnules may occur on the petiole4 ,the pinnules1 #e-bj mm4 in length and #c-h mm4 broad1 have a rounded apex 7fig4 #ced1 ,e1 p4 #ece74 ,illustration3 ,,fig4 #cga4 ,neuropteris heterophylla4 ,from a specimen in the ,manchester ,museum4 nat4 size4 ,m4,s4 ,as shown in fig4 #cga which represents a primary pinna1 the small pinnules on the lower branches are gradually replaced in the upper portion of the specimen by falcate segments4 ,neuropteris macrophylla1 ,brongniart#aeci4 ,figs4 #ced1 ,d1 ,d2 #cgb4 ,the rachis of the large fronds of this species illustrates the dichotomous habit of many ,neuropteris fronds1 also the occurrence on the petiole of large ,cyclopteroid pinnules 7cf4 fig4 #cgj74 ,the small piece of a pinna reproduced in fig4 #cgb shows the slender attachment of the segments1 the blunt apex1 and the ,neuropteroid venation4 ,single pinnules of this species may be distinguished from those of ,n4 ,scheuchzeri by the blunter apex1 the absence of the pair of small ,cyclopteroid pinnules on the same branch and by the absence of hairs4 ,n4 macrophylla is characteristic of the ,upper ,coal-,measures of ,britain4 ,illustration3 ,,fig4 #cgb4 ,neuropteris macrophylla1 ,brongn4 ,from a photograph by ,mr ,hemingway4 ,neuropteris ,scheuchzeri1 ,hoffmann4 ,figs4 #ced1 ,f2 #cgc4 ,fragments of this well-known ,coal-,measure species were figured by ,scheuchzer in his ,herbarium ,diluvianum#aedj as ,lithosmunda minor1 and by ,lhywd 7,luidius#aeda7 as ,phyllites mineralis as early as #agfj4 ,neuropteris ,scheuchzeri1 so named by ,hoffmann in #ahbf1 is a type which many authors have described under different names4 ,lesquereux#aedb figured it as ,n4 hirsuta from the ,coal-fields of ,pennsylvania1 and under the same name it is recorded by ,fontaine and ,white#aedc from ,permian rocks of ,virginia4 ,the oval patches on the surface of a pinnule described by these authors as sori are certainly not of that nature4 ,the same species is described by ,bunbury#aedd from ,nova ,scotia as ,n4 cordata ,brongn4 var4 angustifolia4 ,for a full synonymy of the species reference should be made to lists published by ,kidston#aede1 ,white#aedf1 and ,zeiller#aedg4 ,illustration3 ,,fig4 #cgc4 ,neuropteris ,scheuchzeri4 ,from a specimen 7v4 #bjji7 in the ,british ,museum4 nat4 size4 ,the large tripinnate fronds are characterised by the long linear- or oval-lanceolate pinnules 7fig4 #cgc7aedh with a pointed apex and numerous bristle-like hairs on the lamina2 two much smaller ,cyclopteroid segments occur at the base of the pinnae which are terminated by the linear leaflets 7fig4 #ced1 ,f1 p4 #ece74 ,neuropteris ,scheuchzeri is characteristic of the ,upper and ,middle ,coal-,measures of ,britain and is recorded from several localities in ,north ,america and the ,continent4 ,zalessky#aedi has recently recorded the species from the ,coal-,measures of ,donetz4 ,the frequent occurrence of detached pinnules points to a caducous habit4 ,even single leaflets can1 however1 be identified by their large size1 the pointed apex1 and hairy lamina4 ,the hairs are preserved as fine oblique lines simulating veins2 they were so described by ,roemer#aeej who took them for cross-connexions between the secondary veins and referred the pinnules to ,gutbier's genus ,dictyopteris4 ,another example of ,neuropteris with hairy pinnules is described from the ,commentry ,coal-field by ,renault and ,zeiller as ,n4 horrida#aeea4 ,the oval-linear1 bluntly rounded1 pinnules are characterised by a median band of hairs on each surface and a narrower strip at the edge of the lamina4 ,cyclopteris4 ,this generic name was created by ,brongniart in #ahbhaeeb for specimens which he believed to be complete single leaves of orbicular or reniform shape similar to those of ,trichomanes reniforme4 ,the lamina is traversed by numerous dichotomously branched veins which spread from the centre of the base4 ,it was suspected by ,lindley and ,hutton#aeec that certain ,cyclopteris leaves belonged to the frond of a species of ,neuropteris1 and some years later ,lesquereux#aeed concluded that ,brongniart's genus was founded on orbicular leaflets of ,neuropteris4 ,in #ahfi ,roehl#aeee figured a specimen of ,neuropteris bearing ,cyclopteroid pinnules on its rachis4 ,it is now universally admitted that ,cyclopteris is not a distinct genus and that the specimens so named were borne as modified pinnules on the main rachis of ,neuropteris and ,odontopteris4 ,it is1 however1 convenient to retain the name for detached leaflets which cannot be referred to the fronds on which they were borne4 ,a specimen found by ,mr ,hemingway in the ,upper ,coal-,measures of ,yorkshire and described in #ahhhaeef affords a striking example of the large size attained by what was probably a frond of ,neuropteris4 ,the piece of main rachis reached a length of over #abj cm4 and bore five pairs of ,cyclopteris pinnules1 some of which were #g cm4 long and #e cm4 broad4 ,the complete frond must have reached a length of at least #d metres4 ,fig4 #cgj shows some typical ,cyclopteroid leaflets on the petiole of a ,neuropteris frond4 ,linopteris4 ,the ,upper ,palaeozoic fronds included in this genus are more familiar as species of ,dictyopteris4 ,potoni#aeeg has1 however1 pointed out that the creation of this name by ,lamouroux in #ahji for a genus of ,brown ,algae which is still retained1 makes it advisable to fall back upon the designation ,linopteris4 ,gutbier#aeeh proposed the genus ,dictyopteris in #ahce3 ,linopteris was first used by ,presl#aeei in #ahch4 ,the fronds so named are identical with species of ,neuropteris except in the anastomosis of the secondary veins2 ,linopteris bears to ,neuropteris the same relation as ,lonchopteris bears to ,alethopteris4 ,as in ,neuropteris1 ,cyclopteroid pinnules occur on the petioles of ,linopteris1 but the veins form a fine reticulum4 ,grand',eury#aefj records the association of ,linopteris ,brongniarti with seeds belonging to the genus ,hexagonocarpon1 a fact which points to the ,pteridosperm nature of the foliage4 ,some fertile pinnules of ,linopteris ,schutzei 7,roemer7 are described by ,zeiller#aefa from ,autun as bearing on the under surface of the lamina two rows of long and pointed sporangia1 probably united in groups4 ,the presumption is that these are microsporangia4 ,fig4 #cgd is a reproduction of a careful drawing1 originally published by ,zeiller#aefb1 of a pinnule of the type-specimen of ,gutbier's species ,linopteris neuropteroides4 ,this species differs from ,linopteris obliqua1 instituted by ,bunbury#aefc for specimens obtained by ,lyell#aefd from the ,coal-,measures of ,nova ,scotia1 in the smaller size of the meshes4 ,linopteris obliqua occurs in the ,upper and ,middle ,coal-,measures of ,britain2 it is recorded by ,zeiller from ,asia ,minor1 by ,lesquereux#aefe from ,pennsylvania1 and by other authors from several ,european localities4 ,the pinnules frequently occur detached from the frond and like those of some species of ,neuropteris were caducous4 ,linopteris is rare in ,british strata4 ,illustration3 ,,fig4 #cgd4 ,linopteris neuropteroides1 ,gutb4 7,pinnule of type-specimen4 ,enlarged4 ,after ,zeiller47 ,alethopteris4 ,the name ,alethopteris1 instituted by ,sternberg#aeff1 is applied to compound fronds often reaching a considerable size1 exhibiting the following features3 ,the linear pinnules are attached by the whole breadth of the base1 with the lower edge of the lamina decurrent and usually continuous with that of the next pinnule 7figs4 #bij1 ,a1 p4 #cii2 #cge74 ,the ultimate segments are entire1 with an acute or rounded apex and often characterised by a fairly thick lamina convex on the upper surface4 ,from a prominent midrib1 continued to the apex of the pinnule1 numerous simple and forked secondary veins are given off at a wide angle1 the decurrent portion of the lamina being supplied by veins direct from the axis of the pinna4 ,in the upper part of a frond or primary pinna the pinnules may be replaced by a continuous1 lobed1 or entire simple lamina4 ,the main rachis occasionally exhibits dichotomous branching1 but the fronds are for the most part constructed on the pinnate plan4 ,single ,cyclopteroid pinnules#aefg occur on the petiole of some species of the genus4 ,in certain species of ,alethopteris the pinnules appear to have been deciduous as in ,didymochlaena among recent ferns#aefh4 ,a piece of cuticle from the upper surface of a pinnule of ,alethopteris ,grandini 7,brongn47 figured by ,zeiller#aefi shows very clearly the polygonal form and straight walls of most of the epidermal cells1 those above the veins being almost rectangular4 ,the position of the sunken stomata is revealed by small circular spaces surrounded by a circle of cells4 ,the absence of fertile specimens of this common genus of ,upper ,carboniferous plants led ,stur#aegj to exclude it from the ferns4 ,although no seeds have so far been found in organic connexion with an ,alethopteris frond1 it is certain that some species1 probably all1 represent the foliage of ,pteridosperms4 ,renault was the first to describe petrified specimens of ,alethopteris fronds exhibiting the anatomical structure of ,myeloxylon 7leaf-axis of ,medullosa74 ,the calcareous nodules from ,english ,coal-seams contain numerous fragments of the ,myeloxylon type of rachis bearing ,alethopteroid pinnules4 ,the constant association of the fronds of ,alethopteris lonchitica and ,trigonocarpon seeds noticed by ,mr ,hemingway in the ,coal-,measures of ,yorkshire led him to regard the species as seed-bearing3 it has since been recognised as the foliage of the ,pteridosperm ,medullosa anglica#aega4 ,grand',eury#aegb has recorded the association in ,french ,coal-fields of species of ,alethopteris with ,trigonocarpon and ,pachytesta seeds4 ,alethopteris lonchitica 7,schlotheim7#aegc4 ,figs4 #cfd1 ,a2 #bij1 ,a4 ,this species1 described by ,schlotheim in #ahbj as ,filicites lonchiticus and previously figured by ,scheuchzer#aegd1 is abundant in the ,middle and ,lower ,coal-,measures of ,britain#aege4 ,it is characterised by large tripinnate fronds1 probably quadripinnate in the lower part1 bearing primary pinnae of a more or less triangular form divided into pinnate branches replaced in the apical region by linear segments4 ,the pinnules1 #h-cj mm4 long and #c-e broad1 are linear- or oval-lanceolate with an obtuse apex2 the upper margin of the lamina is slightly contracted at the base1 while the lower edge is decurrent4 ,illustration3 ,,fig4 #cge4 ,alethopteris ,serlii 7,brongn474 ,from a specimen in the ,york ,museum4 nat4 size4 ,alethopteris ,serlii 7,brongniart7#aegf4 ,fig4 #cge4 ,this species1 figured by ,parkinson in #ahaa1 closely resembles ,a4 lonchitica1 but is distinguished by the more crowded and relatively longer pinnules which are joined to one another by a narrow connecting lamina 7,fig4 #cge74 ,the secondary veins in ,a4 ,serlii are rather finer and more numerous4 ,grand',eury#aegg records the association of the seed ,pachytesta with fronds of this species in the ,coal-,measures of ,st tienne4 ,a4 ,serlii is very abundant in the ,upper ,coal-,measures but rare in the ,middle ,coal-,measures of ,britain#aegh4 ,lonchopteris4 ,this name was proposed by ,brongniart#aegi for sterile fronds from ,upper ,carboniferous rocks which are practically identical with species of ,alethopteris1 but differ in the reticulate venation of the pinnules4 ,it has been pointed out in a previous chapter#aehj that ,lonchopteris is usually used for ,palaeozoic species1 the ,wealden leaves1 which were placed in this genus by ,brongniart1 being transferred to ,weichselia4 ,there can be little doubt as to the close relationship of ,lonchopteris with ,alethopteris3 both may be referred to the ,pteridosperms4 ,lonchopteris rugosa ,brongn4#aeha 7fig4 #bij1 ,b1 p4 #cii7 and ,l4 ,bricei ,brongn41 both ,british species1 are fairly common in ,upper ,carboniferous strata4 ,in ,l4 rugosa1 a ,middle ,coal-,measures species1 the anastomosing secondary veins form polygonal meshes 7fig4 #bij1 ,b1 p4 #cii7 smaller than those of ,l4 ,bricei4 ,pecopteris4 ,reference has already been made to this genus in the chapter on ,marattiales1 so far as regards certain species of fertile fronds the sporangia of which resemble those of recent ,marattiaceae4 ,it is1 however1 by no means safe to assume that such ,pecopteris fronds were borne on stems having the anatomical characters of ferns4 ,the sporangia in some at least of the species may have contained microspores4 ,in one ,upper ,carboniferous species usually referred to ,pecopteris1 ,p4 ,pluckeneti1 ,schlot41 ,grand',eury#aehb has recorded the occurrence of seeds on the pinnules of the ordinary fronds4 ,this species will be referred to in ,volume ,,iii4 ,the substitution of such generic names as ,ptychocarpus1 ,asterotheca1 ,hawlea1 ,dactylotheca and others for the purely provisional designation ,pecopteris indicates a step towards a conclusion as to natural affinity4 ,the probability is that ,pecopteris1 as applied to ,palaeozoic species1 in many cases stands for the compound fronds of true ferns1 but the possibility of the inclusion of those of ,pteridosperms in the same category is by no means excluded4 ,the designation ,pecopteris may conveniently be retained for sterile bipinnate1 tripinnate1 or quadripinnate fronds bearing pinnules having the following characteristics3 ,lamina short1 attached to the rachis by the whole of the base and at a wide angle1 with the edges parallel or slightly converging towards the usually blunt apex2 adjacent pinnules may be continuous basally by a narrow lamina4 ,a well-marked midrib extends to the apex and gives off simple or forked lateral veins almost at right angles 7fig4 #ceb1 ,d1 p4 #ebi74 ,hydathodes like those on the leaflets of ,polypodium vulgare and other recent ferns#aehc are occasionally seen at the ends of the lateral veins of ,pecopteris pinnules4 ,in addition to the examples of ,palaeozoic fronds with the ,pecopteris form of pinnule referred to in chapter ,,xxii41 the species ,pecopteris arborescens may be briefly described4 ,pecopteris arborescens 7,schlotheim7#aehd4 ,figs4 #ceb1 ,d3 #cgf4 ,the species named by ,schlotheim ,filicites arborescens in #ahjd is characteristic of the ,upper ,coal-,measures and is recorded also from ,permian strata#aehe4 ,fronds large2 the rachis1 which may reach a breadth of #c cm4#aehf1 gives off long ovoid-lanceolate pinnae in two alternate rows 7fig4 #cgf72 pinnules small1 #ae-dmm4 long and #a-bmm4 broad1 contiguous1 with rounded apex1 attached approximately at right angles2 the upper surface of the lamina is slightly convex and may be hairy#aehg4 ,the fertile pinnules1 identical in shape with the sterile1 bear groups of ovoid exannulate sporangia 7synangia74 ,the midrib extends to the apex of the pinnule and gives off simple veins at a wide angle 7fig4 #ceb1 ,d74 ,our knowledge of the reproductive organs is very meagre4 ,grand',eury described the synangia as consisting of #c-e sporangia borne on a central receptacle2 sporangia have been described also by ,stur#aehh1 ,renault and ,zeiller#aehi1 and ,potoni#aeij1 but no fertile ,british specimens are recorded4 ,stur places this species in the genus ,scolecopteris1 and ,potoni regards the sporangia found by him on ,permian fronds1 which may be identical with ,pecopteris arborescens1 as conforming to those of the ,asterotheca type4 ,it is impossible to decide on the evidence available whether this species is a ,pteridosperm or a fern1 but there is a natural inclination in doubtful cases to give preference to the first of these two choices4 ,illustration3 ,,fig4 #cgf4 ,pecopteris arborescens 7,schloth474 ,from the ,upper ,coal-,measures of ,radstock4 ,from a photograph by ,dr ,kidston4 ,reduced4 ,the numerous fronds from ,carboniferous and ,permian rocks described as species of ,pecopteris exhibit a considerable range of variation in the form of the pinnules4 ,in many species the pinnules are of the type represented in fig4 #ceb1 ,d2 in others the lamina of the ultimate segments is slightly contracted at the base and the secondary veins are given off at a more acute angle1 as in ,pecopteris polymorpha1 ,brongn4#aeia ,in ,pecopteris unita1 ,brongn41 already described as ,ptychocarpus unita#aeib1 the pinnules are joined together except in the apical region4 ,some fronds included in ,pecopteris possess pinnules in which ,pecopteroid and ,sphenopteroid features are combined2 ,p4 ,sterzeli1 ,zeill4#aeic and ,p4 ,pluckeneti1 ,schlot4 are examples of fronds in which the pinnules are lobed as in ,sphenopteris1 but the base of the lamina is only slightly contracted and the venation is not that of typical ,sphenopteris species4 ,the species to which ,potoni has applied the generic name ,alloiopteris#aeid also illustrates the impossibility of drawing a sharp line between ,pecopteris and ,sphenopteris4 ,the fronds already described in chapter ,,xxv4 under the designation ,corynepteris bear pinnules with a contracted base2 in some species the lamina is lobed1 but in others 7fig4 #ced1 ,g7 it is entire with a midrib nearer one edge than the other4 ,the species which ,potoni assigns to ,alloiopteris1 like many other ,sphenopteroid and ,pecopteroid fronds1 are characterised by the occurrence of an abnormal pinnule 7aphlebia7 at the base of each pinna 7fig4 #ced1 ,g1 p4 #ece74 ,young fronds of ,pecopteris are occasionally met with showing very clearly the circinate vernation of the pinnae as in the leaves of ,cycas and ,angiopteris represented in fig4 #bbj1 p4 #bhc4 ,the genus ,spiropteris was created by ,schimper#aeie for coiled unexpanded fronds of fossil ferns2 it is however superfluous to apply a distinctive term to specimens of this kind4 ,the designation ,pecopteris is employed chiefly for leaves of ,palaeozoic age which are unknown in the fertile state1 or do not afford sufficient evidence as to the nature of the sporangia to justify the substitution of a special generic name4 ,many ,mesozoic species have also been referred to ,pecopteris1 but most of these are more appropriately included in ,brongniart's later genus ,cladophlebis4 ,the pinnules of ,cladophlebis1 as ,brongniart pointed out1 are intermediate between ,pecopteris and ,neuropteris2 they are usually attached by the whole breadth of the base1 as in ,pecopteris1 but the more acute origin1 more arched form1 and more frequent dichotomy of the lateral veins are features shared by ,neuropteris4 ,as a rule1 ,mesozoic sterile fronds with straight or folded1 entire or dentate pinnules are of the ,cladophlebis type3 this genus is especially characteristic of ,rhaetic and ,jurassic floras4 ,examples of ,cladophlebis pinnules are shown in figs4 #bef1 #beg 7pp4 #cdj1 #cdb74 ,it is to be regretted that authors do not make more use of the generic name ,cladophlebis in describing sterile fronds1 instead of following the misleading and unscientific practice of employing such genera as ,pteris1 ,asplenites1 and others on wholly insufficient grounds4 ,,list ,,of ,,works ,,referred ,,to ,,in ,,the ,,text4 ,amalitzky1 ,w4 7#ja7 ,sur la dcouverte1 dans les dpts permiens suprieurs du ,nord de la ,russie1 d'une flore ,glossoptrienne c4 ,compt4 ,rend4 vol4 ,,cxxxii4 p4 #eia4 ,arber1 ,e4 ,a4 ,n4 7#jb7 ,on the distribution of the ,glossopteris ,flora4 ,geol4 ,mag4 vol4 ,,ix4 p4 #cdf4 ---- 7#jb7 ,the ,clarke collection of fossil plants from ,new ,south ,wales4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,lviii4 p4 #a4 ---- 7#jc7 ,notes on some fossil plants collected by ,mr ,molyneux in ,rhodesia4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,lix4 p4 #bhh4 ---- 7#je7 ,catalogue of the fossil plants of the ,glossopteris ,flora in the ,british ,museum4 ,a monograph of the ,permo-,carboniferous ,flora of ,india and the ,southern ,hemisphere4 ,london4 ---- 7#je7 ,the ,sporangium-like organs of ,glossopteris ,browniana1 ,brongn4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,lxi4 p4 #cbd ---- 7#je7 ,the fossil flora of the ,culm-measures of ,n4 ,w4 ,devon c4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,cxcvii4 p4 #bia4 ---- 7#jf7 ,on the past history of ,ferns4 ,annals ,bot4 vol4 ,,xx4 p4 #bae4 ,arber1 ,e4 ,a4 ,n4 and ,h4 ,h4 ,thomas4 7#jh7 ,on the structure of ,sigillaria scutellata1 ,brongn4 and other ,eusigillarian stems1 in comparison with those of other ,palaeozoic ,lycopods4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,cc4 p4 #acc4 ,armour1 ,h4 ,m4 7#jg7 ,on the ,sorus of ,dipteris4 ,new ,phytologist1 vol4 ,,vi4 p4 #bch4 ,atkinson1 ,g4 ,f4 7#id7 ,the study of the biology of ,ferns1 by the collodion method4 ,new ,york4 ,auerbach1 ,j4 and ,h4 ,trautschold4 7#fj7 ,ueber die ,kohlen von ,central ,russland4 ,nouv4 ,mm41 ,soc4 ,imp4 ,naturalistes ,moscou1 vol4 ,,xiii4 ,bsecke1 ,p4 7#jh7 ,beitrge zur ,kenntnis der physiologischen ,scheiden der ,achsen und ,wedel der ,filicinen c4 ,bot4 ,zeit4 ,heft ,,ii4-,,iv4 ,abt4 ,i4 ,baily1 ,w4 ,h4 7#ei7 ,on the fructification of ,cyclopteris hibernica 7,forbes71 from the ,upper ,devonian or ,lower ,carboniferous strata at ,kiltorkan ,hill1 ,county ,kilkenny4 ,brit4 ,assoc4 ,rep4 ,london1 #ahei1 p4 #ge4 7,leeds meeting1 #aheh47 ---- 7#fj7 ,on ,corynepteris1 a new generic form of fossil fern4 ,journ4 ,geol4 ,soc4 ,dublin1 vol4 ,,viii4 p4 #bcg4 ---- 7#ge7 ,figures of characteristic ,british fossils4 ,london4 ,baker1 ,j4 ,g4 7#fg7 ,descriptions of six new species of simple fronded ,hymenophyllaceae4 ,journ4 ,linn4 ,soc4 vol4 ,,ix4 p4 #cce4 ---- 7#fh7 ,on the geographical distribution of ,ferns4 ,trans4 ,linn4 ,soc4 vol4 ,,xxvi4 p4 #cje4 ---- 7#fh7 ,see ,hooker1 ,sir ,w4 ,j4 and ,j4 ,g4 ,baker4 ---- 7#hh7 ,on a further collection of ferns from ,west ,borneo4 ,journ4 ,linn4 ,soc4 vol4 ,,xxiv4 p4 #bef4 ,balfour1 ,j4 ,h4 7#eg7 ,on the occurrence in coal of peculiar vegetable organisms resembling the ,sporangia of ,lycopodium4 ,trans4 ,r4 ,soc4 ,edin4 vol4 ,,xxi4 p4 #ahg4 ,barber1 ,c4 ,a4 7#hi7 ,on the structure and development of the bulb in ,laminaria bulbosa1 ,lamour4 ,annals ,bot4 vol4 ,,iii4 p4 #da4 ,barrois1 ,c4 7#jd7 ,sur les ,spirorbes du ,terrain ,houiller de ,bruay4 7,pas de ,calais47 ,ann4 ,soc4 ,geol4 ,nord1 vol4 ,,xxxiii4 p4 #ej4 ,bartholin1 ,c4 ,t4 7#ib7 ,nogle i den bornholmske ,juraformation forekommende ,planteforsteninger4 ,bot4 ,tidsk4 ,kjvenhaven1 vol4 ,,xviii4 ,heft #a4 ,bather1 ,f4 ,a4 7#jg7 ,nathorst's use of ,collodion imprints in the study of fossil plants4 ,geol4 ,mag4 vol4 ,,iv4 p4 #dcg4 ---- 7#jh7 ,nathorst's method of studying cutinised portions of fossil plants4 ,geol4 ,mag4 vol4 ,v4 p4 #ded4 ,bayer1 ,g4 7#ii7 ,einige neue ,pflanzen der ,perucer ,kreideschichten in ,bhmen4 ,sitz4 ,k4 bhm4 ,ges4 ,wiss4 ,prag4 ,bennie1 ,j4 and ,r4 ,kidston4 7#hh7 ,on the occurrence of ,spores in the ,carboniferous formation of ,scotland4 ,proc4 ,r4 ,physc4 ,soc4 ,edin4 vol4 ,,ix4 p4 #hb1 #ahhe-hh4 ,benson1 ,margaret4 7#jd7 ,telangium ,scotti1 a new species of ,telangium 7,calymmatotheca7 showing structure4 ,ann4 ,bot4 vol4 ,,xviii4 p4 #afa4 ---- 7#jh7 ,miadesmia membranacea1 ,bertrand2 a new ,palaeozoic ,lycopod with a seed-like structure4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,cxcix4 p4 #dji4 ---- 7#jh7 ,the ,sporangiophore--a unit of structure in the ,pteridophyta4 ,new ,phytologist1 vol4 ,,vii4 p4 #adc4 ,bernard1 ,c4 7#jd7 ,le bois centripte dans les feuilles de ,conifres4 ,bot4 ,cent4 ,beiheft1 vol4 ,,xvii4 p4 #bda4 ,berridge1 ,e4 ,m4 7#je7 ,on two new specimens of ,spencerites insignis4 ,ann4 ,bot4 vol4 ,,xix4 p4 #bgc4 ,berry1 ,e4 ,w4 7#jc7 ,the ,american species referred to ,thinnfeldia4 ,bull4 ,torrey ,bot4 ,club1 vol4 ,,xxx4 p4 #dch4 ,bertrand1 ,c4 ,e4 7#ha7 ,recherches sur les ,tmsiptrides4 ,arch4 ,bot4 ,nord de la ,france1 vol4 ,i4 p4 #beb4 ---- 7#hb7 ,phylloglossum4 ,arch4 ,bot4 ,nord ,france1 vol4 ,,ii4 p4 #gj4 ---- 7#ia7 ,remarques sur le ,lepidodendron ,harcourtii de ,witham4 ,trav4 ,mm4 ,fac4 ,lille1 vol4 ,,ii4 ,mm4 #f4 ---- 7#id7 ,sur une nouvelle ,centradesmide4 ,assoc4 ,fran4 pour l',avancement des ,sciences4 ---- 7#ii7 ,on the structure of the stem of a ribbed ,sigillaria4 ,ann4 ,bot4 vol4 ,,xiii4 ---- and ,f4 ,cornaille4 7#jb7 tudes sur quelques caractristiques de la structure des ,filicines actuelles4 ,trav4 ,mem4 ,l',univ4 ,lille1 tome ,x4 ,mm4 #bi4 ,bertrand1 ,p4 7#ji7 tudes sur la ,fronde des ,zygoptrides4 ,lille4 ,binney1 ,e4 ,w4 7#dd7 ,on the remarkable fossil trees lately discovered near ,st ,helen's4 ,phil4 ,mag4 vol4 ,,xxiv4 p4 #afe4 ---- 7#df7 ,description of the ,dukinfield ,sigillaria4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,ii4 p4 #cij4 ---- 7#dh7 ,on the origin of coal4 ,manchester ,phil4 ,soc4 ,mem4 vol4 ,,viii4 p4 #adh4 ---- 7#fb7 ,on some plants showing structure from the ,lower ,coal-,measures of ,lancashire4 ,proc4 ,geol4 ,soc4 vol4 ,,xxviii4 p4 #ajf4 ---- 7#fe7 ,a description of some fossil plants showing structure1 found in the ,lower ,coal-,seams of ,lancashire and ,yorkshire4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,clv4 pt4 ii4 p4 #egi4 ---- 7#ga7 ,observations on the structure of fossil plants found in the ,carboniferous ,strata4 ,palaeont4 ,soc4 ,london4 ---- 7#gb7 ,observations c4 ,pt4 ,,iii4 ,lepidodendron4 ,palaeont4 ,soc4 ,bischof1 -- 7#ec7 ,sigillarien aus dem bunten ,sandstein ,bernburgs4 ,zeit4 ,gesammt4 ,naturwiss4 ,bd4 ,i4 ,blanckenhorn1 ,m4 7#he7 ,die ,fossile ,flora des ,buntsandsteins und des ,muschelkalkes der ,umgegend von ,commern4 ,palaeontographica1 vol4 ,,xxxii4 p4 #aag4 ,bommer1 ,c4 7#jc7 ,les causes d'erreur dans l'tude des empreintes vgtales4 ,nouv4 ,mm4 ,soc4 ,belg4 ,geol4 c4 ,fasc4 ,i4 ,boodle1 ,l4 ,a4 7#jj7 ,comparative anatomy of the ,hymenophyllaceae1 ,schizaeaceae1 and ,gleicheniaceae4 ,annals ,bot4 vol4 ,,xiv4 p4 #dee4 ---- 7#ja7 ,comparative anatomy of the ,hymenophyllaceae1 ,schizaeaceae1 and ,gleicheniaceae4 ,annals ,bot4 vol4 ,,xiv4 p4 #cei4 ---- 7#jd7 ,on the occurrence of ,secondary ,xylem in ,psilotum4 ,ann4 ,bot4 vol4 ,,xviii4 p4 #eje4 ---- 7#jd7 ,the structure of the leaves of the bracken 7,pteris aquilina1 ,l47 in relation to environment4 ,journ4 ,linn4 ,soc4 ,london1 vol4 ,,xxxv4 p4 #fei4 ---- 7#jh7 ,on the production of dwarf male prothalli in sporangia of ,todea4 ,ann4 ,bot4 vol4 ,,xxii4 p4 #bca4 ,boulay1 ,n4 7#gf7 ,le ,terrain ,houiller du ,nord de la ,france et les ,vgtaux ,fossiles4 ,lille4 ,bower1 ,f4 ,o4 7#ia7 ,is the ,eusporangiate or the ,leptosporangiate the more primitive type in the ferns8 ,annals ,bot4 vol4 ,v4 p4 #aji4 ---- 7#ic7 ,on the structure of ,lepidostrobus ,brownii1 ,schmpr4 ,annals ,bot4 vol4 ,,vii4 p4 #cbi4 ---- 7#id7 ,studies in the ,morphology of ,spore-producing ,members4 ,equisetaceae and ,lycopodineae4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,clxxxv4 p4 #dgc4 ---- 7#if7 ,studies c4 ,,ii4 ,ophioglossaceae4 ,london4 ---- 7#ig7 ,studies c4 ,,iii4 ,marattiaceae4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,clxxxix4 p4 #ce4 ---- 7#jj7 ,studies c4 ,,iv4 ,the ,leptosporangiate ,ferns4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,cxcii4 p4 #bi4 ---- 7#jd7 ,studies c4 ,v4 ,general ,comparisons and ,conclusions4 ,ibid4 vol4 ,,cxcvi4 p4 #aia4 ---- 7#jh7 ,the origin of a ,land ,flora4 ,london4 ,bowman1 ,j4 ,e4 7#da7 ,observations on the characters of the fossil trees lately discovered on the line of the ,bolton railway4 ,trans4 ,manchester ,geol4 ,soc4 vol4 ,i4 p4 #aab4 ,braun1 ,a4 7#fc7 ,ueber die ,isoetes ,arten der ,insel ,sardinien4 ,monatsber4 k4 ,preuss4 ,akad4 ,wiss4 ,berlin4 ,braun1 ,f4 7#ge7 ,die ,frage nach der ,gymnospermie der ,cycadeen4 ,monatsber4 k4 ,preuss4 ,akad4 ,wiss4 p4 #bda4 ,brebner1 ,g4 7#jb7 ,the anatomy of ,danaea and other ,marattiaceae4 ,ann4 ,bot4 vol4 ,,xvi4 ,brodie1 ,p4 ,b4 7#db7 ,on the discovery of insects in the ,lower ,beds of the ,lias of ,gloucestershire4 ,brit4 ,assoc4 ,rep4 #ahdb1 p4 #eh4 ---- 7#de7 ,a history of fossil insects in the ,secondary ,rocks of ,england1 ,london4 ,brongniart1 ,a4 7#be7 ,note sur les vgtaux fossiles de l',oolite fougres de ,mamers4 ,ann4 ,sci4 ,nat4 tome ,,iv4 p4 #dag4 ---- 7#cg7 ,histoire des ,vgtaux ,fossiles1 vol4 ,,ii4 ,paris4 ---- 7#de7 ,see ,murchison1 ,r41 de ,verneuil1 and ,count ,keyserling4 ---- 7#fh7 ,notice sur un ,fruit de ,lycopodiaces ,fossiles4 ,compt4 ,rend4 vol4 ,,lxvii4 ,aug4 #agth4 ,brown1 ,r4 7#de7 ,on the geology of ,cape ,breton4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,i4 p4 #bjg4 ---- 7#df7 ,on a group of erect trees in the ,sydney coalfield of ,cape ,breton4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,ii4 p4 #cic4 ---- 7#dg7 ,upright ,lepidodendron with ,stigmaria roots1 in the roof of ,sydney ,main ,coal4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,iv4 p4 #df4 ---- 7#di7 ,description of erect ,sigillariae with conical tap-roots1 found in the roof of the ,sydney ,main ,coal1 in the island of ,cape ,breton4 ,proc4 ,geol4 ,soc4 7,march #ba71 p4 #ced4 ---- 7#ea7 ,some account of an undescribed fossil fruit 7,triplosporites74 ,trans4 ,linn4 ,soc4 vol4 ,,xx4 p4 #dfi4 ,browne1 ,lady ,isabel4 7#ji7 ,the phylogeny and inter-relationships of the ,pteridophyta4 ,new ,phytologist 7,reprint1 ,no4 #c74 ,cambridge4 ,bruchmann1 ,h4 7#gd7 ,ueber ,anlage und ,wachsthum der ,wurzeln von ,lycopodium und ,isoetes4 ,jen4 ,zeit4 ,naturwiss4 vol4 ,,viii4 p4 #ebb4 ---- 7#ig7 ,untersuchungen ber ,selaginella spinulosa1 ,a4 ,br4 ,gotha4 ---- 7#ih7 ,ueber die ,prothallien und die ,keimpflanzen mehrerer ,europischer ,lycopodien4 ,gotha4 ,buckman1 ,j4 7#de7 ,see ,murchison1 ,r4 ,i4 ---- 7#ej7 ,on some fossil plants from the ,lower ,lias4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,vi4 p4 #dac4 ,bunbury1 ,c4 ,j4 ,f4 7#dg7 ,on fossil plants from the coal formation of ,cape ,breton4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,iii4 p4 #dbc4 ---- 7#fa7 ,notes on a collection of fossil plants from ,nagpur1 ,central ,india4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xvii4 p4 #cbe4 ,butterworth1 ,j4 7#jj7 ,further research on the structure of ,psaronius1 a tree-fern of the ,coal-,measures4 ,mem4 ,proc4 ,manchester ,lit4 ,phil4 ,soc4 vol4 ,,xliii4 ,campbell1 ,d4 ,h4 7#jd7 ,the affinities of the ,ophioglossaceae and ,marsiliaceae4 ,amer4 ,naturalist1 vol4 ,,xxviii4 no4 #ded4 ---- 7#je7 ,the structure and development of ,mosses and ,ferns4 ,new ,york4 ---- 7#jg7 ,on the distribution of the ,hepaticae and its significance4 ,new ,phytol4 vol4 ,,vi4 p4 #bjc4 ,carruthers1 ,w4 7#fe7 ,on ,caulopteris punctata1 ,gpp41 a tree-fern from the ,upper ,greensand of ,shaftesbury in ,dorsetshire4 ,geol4 ,mag4 vol4 ,,ii4 p4 #dhd4 ---- 7#fi7 ,on the structure of the stems of arborescent ,lycopodiaceae of the ,coal-,measures4 ,month4 ,micr4 ,journ4 p4 #agg4 ---- 7#fi7 ,on the plant-remains from the ,brazilian coal-beds1 with remarks on the genus ,flemingites4 ,geol4 ,mag4 vol4 ,,vi4 p4 #e4 ---- 7#gj7 ,on the nature of the scars in the stems of ,ulodendron1 ,bothrodendron1 and ,megaphytum4 ,monthly ,micr4 ,journ4 p4 #add4 ---- 7#gb7 ,on the structure of the stems of the arborescent ,lycopodiaceae of the ,coal-,measures4 ,monthly ,micr4 ,journ4 p4 #ej4 ---- 7#gb7 ,notes on fossil plants from ,queensland1 ,australia4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xxviii4 ---- 7#gb7 ,notes on some fossil plants4 ,geol4 ,mag4 vol4 ,,ix4 ---- 7#gc7 ,on some ,lycopodiaceous plants from the ,old ,red ,sandstone of the ,north of ,scotland4 ,journ4 ,bot41 ,november1 #ahgc4 ---- 7#gc7 ,on ,halonia of ,lindley and ,hutton and ,cyclocladia of ,goldenberg4 ,geol4 ,mag4 vol4 ,x4 p4 #ade4 ,cash1 ,w4 and ,j4 ,lomax4 7#ij7 ,on ,lepidophloios and ,lepidodendron4 ,brit4 ,ass4 ,rep4 7,leeds71 p4 #haj4 ,challenger ,reports4 7#he7 ,reports on the scientific results of the voyage of ,h4 ,m4 ,s4 ,challenger during the years #ahgc-gf4 ,narrative1 vol4 ,i4 pts4 #a and #b4 ,london4 ---- 7#he7 ,ibid4 ,botany1 vol4 ,i4 ,chick1 ,edith4 7#ja7 ,see ,tansley1 ,a4 ,g4 and ,edith ,chick4 ,chodat1 ,r4 7#jh7 ,les ,ptridopsides des temps ,palozoques4 ,arch4 ,soc4 ,phys4 ,nat4 #d1 vol4 ,,xxvi4 ,genoa4 ,christ1 ,h4 7#if7 ,zur ,farn-,flora der ,sunda ,inseln4 ,ann4 ,jard4 ,buitenzorg1 vol4 ,,xiii4 p4 #ij4 ---- 7#ig7 ,die ,farnkruter der ,erde4 ,jena4 ---- 7#jd7 ,loxsomopsis costaricensis nov4 gen4 et spec4 ,bull4 ,herb4 ,boissier #b vol4 ,,iv4 ,no4 #e4 ---- and ,k4 ,giesenhagen4 7#ii7 ,pteridographische ,notizen1 ,i4 ,archangiopteris nov4 gen4 ,flora1 ,bd4 ,,lxxxvi4 p4 #gb4 ,chrysler1 ,m4 ,a4 7#jh7 ,tyloses in tracheids of ,conifers4 ,new ,phytologist1 vol4 ,,vii4 ,compton1 ,r4 ,h4 7#ji7 ,the anatomy of ,matonia sarmentosa4 ,new ,phyt4 vol4 ,,viii4 p4 #bii4 ,copeland1 ,e4 ,b4 7#jh7 ,new genera and species of ,bornean ferns4 ,the ,philippine ,journ4 ,sci4 vol4 ,,iii4 7,c4 ,botany7 p4 #cdc4 ---- 7#ji7 ,the ferns of the ,malay ,asiatic region4 ,ibid4 vol4 ,,iv4 ,no4 #a4 ,corda1 ,a4 ,j4 7#df7 ,see ,reuss1 ,a4 ,e4 ---- 7#eb7 ,see ,germar1 ,e4 ,f4 ,cornaille1 ,f4 7#jb7 ,see ,bertrand1 ,c4 ,e4 and ,f4 ,cornaille4 ,cotta1 ,c4 ,b4 7#cb7 ,die ,dendrolithen in ,beziehung auf ihren inneren ,bau4 ,dresden4 ,coward1 ,k4 ,h4 7#jg7 ,on the structure of ,syringodendron1 the bark of ,sigillaria4 ,mem4 ,proc4 ,manchester ,lit4 ,phil4 ,soc4 vol4 ,,li41 pt4 ii4 ,crpin1 ,f4 7#gd7 ,description de quelques plantes fossiles de l'tage des ,psammites de ,condroz4 ,bull4 ,acad4 ,roy4 ,belg4 #b vol4 ,,xxxviii4 ---- 7#ge7 ,observations sur quelques plantes fossiles des dpts ,dvoniens4 ,soc4 ,roy4 bot4 ,belg4 vol4 ,,xiv4 p4 #bad4 ,dale1 ,e4 7#ja7 ,see ,seward1 ,a4 ,c4 and ,e4 ,dale4 ,dangeard1 ,p4 ,a4 7#ia7 ,mmoire sur la morphologie et l'anatomie des ,tmesipteris4 ,le ,botaniste #a ,fasc4 ,,vi4 p4 #afc4 ,darwin1 ,c4 7#jc7 ,more letters of ,charles ,darwin1 edited by ,f4 ,darwin and ,a4 ,c4 ,seward 7vol4 ,,ii474 ,london4 ,david1 ,w4 ,e4 and ,e4 ,f4 ,pittman4 7#ic7 ,on the occurrence of ,lepidodendron australe 787 in the ,devonian rocks of ,n4 ,s4 ,wales4 ,rec4 ,geol4 ,surv4 ,n4 ,s4 ,wales1 vol4 ,,iii4 pt4 iv4 p4 #aid4 ,davy1 ,e4 ,w4 7#jg7 ,summer in ,british ,central ,africa4 ,gard4 ,chron4 vol4 ,,xli4 #c p4 #bfc4 ,dawes1 ,j4 ,s4 7#dh7 ,remarks upon the internal structure of ,halonia4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,iv4 p4 #bhi4 ,dawson1 ,sir ,j4 ,w4 7#fa7 ,on an undescribed fossil fern from the ,lower ,coal-,measures of ,nova ,scotia4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xvii4 p4 #e4 ---- 7#ff7 ,acadian ,geology4 ,london4 ---- 7#hb7 ,the fossil plants of the ,erian and ,upper ,silurian ,formations of ,canada4 ,pt4 ,,ii4 ,geol4 ,surv4 ,canada4 ---- 7#hf7 ,on ,rhizocarps in the ,erian 7,devonian7 period in ,america4 ,bull4 ,chicago ,acad4 ,sci4 vol4 ,i4 no4 #i4 ,debey1 ,m4 ,h4 and ,c4 von ,ettingshausen4 7#ei7 ,die urweltlichen ,acrobryen des ,kreidegebirges von ,aachen und ,maestricht4 ,denksch4 k4 ,akad4 ,wiss4 ,wien1 vol4 ,,xvii4 ,diels1 ,l4 7#jb7 ,filicales4 ,die ,natrlichen ,pflanzenfamilien4 ,engler and ,prantl1 ,teil ,i4 ,abt4 #d4 ,eichwald1 ,e4 7#fj7 ,lethaea ,rossica4 ,vol4 ,i4 ,stuttgart4 ,engler1 ,a4 7#ji7 ,syllabus der ,pflanzenfamilien4 ,berlin4 ---- and ,k4 ,prantl4 7#jb7 ,die ,natrlichen ,pflanzenfamilien4 ,leipzig4 ,ernst1 ,a4 7#jh7 ,the new flora of the volcanic island of ,krakatau4 7,trans4 by ,a4 ,c4 ,seward47 ,cambridge4 ,etheridge1 ,r4 7#hj7 ,a contribution to the study of ,british ,carboniferous ,tubicolar ,annelida4 ,geol4 ,mag4 vol4 ,,vii4 p4 #aji4 ---- ,lepidodendron australe1 ,mc,coy4--,its synonyms and range in ,eastern ,australia4 ,rec4 ,geol4 ,surv4 ,n4 ,s4 ,wales1 vol4 ,,ii4 pt4 #c1 p4 #aai4 ---- 7#ib7 ,see ,jack1 ,r4 ,l4 and ,r4 ,etheridge4 ---- 7#id7 ,on the mode of attachment of the leaves or fronds to the caudex in ,glossopteris4 ,proc4 ,linn4 ,soc4 ,n4 ,s4 ,wales1 vol4 ,,ix4 p4 #bbh4 ---- 7#id7 ,on the occurrence of ,oleandridium in the ,hawkesbury ,sandstone series4 ,rec4 ,geol4 ,surv4 ,n4 ,s4 ,wales1 vol4 ,,iv4 pt4 #b1 p4 #di4 ---- 7#ii7 ,on a fern 7,blechnoxylon talbragarense7 with secondary wood1 forming a new genus1 from the ,coal-,measures of the ,talbragar ,district1 ,n4 ,s4 ,wales4 ,rec4 ,australian ,mus4 vol4 ,,iii4 pt4 #f4 ,ettingshausen1 ,c4 von4 7#eb7 ,begrndung einiger neuen oder nicht genau bekannten ,arten der ,lias- und der ,oolithflora4 ,abt4 ,k4 ,k4 ,geol4 ,reichs1 vol4 ,i4 ,abth4 #c4 ---- 7#ei7 ,see ,debey1 ,m4 ,h4 and ,c4 von ,ettingshausen4 ---- 7#ff7 ,die ,fossile ,flora des mhrisch-schlesischen ,dachschiefers4 ,denksch4 ,k4 ,k4 ,akad4 ,wien1 vol4 ,,xxv4 p4 #gg4 ---- 7#hb7 ,see ,gardner1 ,j4 ,s4 and ,c4 von ,ettingshausen4 ,farmer1 ,j4 ,b4 7#ij7 ,on ,isoetes lacustris1 ,l4 ,annals ,bot4 vol4 ,v4 p4 #cg4 ,farmer1 ,j4 ,b4 and ,w4 ,g4 ,freeman4 7#ii7 ,on the structure and affinities of ,helminthostachys zeylanica4 ,annals ,bot4 vol4 ,,xiii4 p4 #dba4 ,farmer1 ,j4 ,b4 and ,t4 ,g4 ,hill4 7#jb7 ,on the arrangement and structure of the vascular strands in ,angiopteris evecta c4 ,annals ,bot4 vol4 ,,xvi4 p4 #cga4 ,faull1 ,j4 ,h4 7#ja7 ,the anatomy of the ,osmundaceae4 ,bot4 ,gaz41 vol4 ,,xxxii4 p4 #cha4 ,feistmantel1 ,c4 7#gi7 ,ueber die ,nggerathien4 ,sitz4 ,k4 bhm4 ,ges4 ,wiss4 ,feistmantel1 ,o4 7#gb7 ,ueber ,baumfarrenreste der bhmischen ,steinkohlen4 ,perm4 und ,kreideformation4 ,abt4 k4 bhm4 ,ges4 ,wiss4 vol4 ,,vi4 #e4 ---- 7#ge7 ,die ,versteinerungen der bhmischen ,kohlenablagerungen4 ,palaeontograph4 vol4 ,,xxiii4 #ahge-gf4 ---- 7#ge7 ,ueber das ,vorkommen von ,noggerathia foliosa1 ,stbg41 in dem ,steinkohlengebirge von ,oberschlesien4 ,zeit4 ,deutsch4 ,geol4 ,ges4 ---- 7#gg7 ,jurassic 7,liassic7 ,flora of the ,rajmahal group from ,golapili 7near ,ellore71 ,s4 ,godaveri ,district4 ,mem4 ,geol4 ,surv4 ,india1 vol4 ,i4 pt4 iii4 ---- 7#gi7 ,the ,flora of the ,talchir-,karharbri ,beds4 ,mem4 ,geol4 ,surv4 ,india4 ,foss4 ,flor4 ,lower ,gondwanas1 ,i4 ---- 7#hj7 ,the ,flora of the ,damuda and ,panchet ,divisions4 ,mem4 ,geol4 ,surv4 ,india4 ,ibid4 vol4 ,,iii4 ---- 7#hb7 ,the ,fossil ,flora of the ,south ,rewah ,gondwana ,basin4 ,ibid4 vol4 ,,iv4 pt4 i4 ,fischer1 ,f4 7#jd7 ,zur ,nomenclatur von ,lepidodendron und zur ,artkritik dieser ,gattung4 ,abh4 k4 ,preuss4 ,geol4 ,landes4 ,n4,f4 ,heft ,,xxxix4 ,fitting1 ,h4 7#jg7 ,sporen im ,buntsandstein4 ,die ,makrosporen von ,pleuromeia4 ,ber4 ,deutsch4 ,bot4 ,ges4 vol4 ,,xxv4 p4 #dcd4 ,fliche1 ,p4 7#jc7 ,sur les ,lycopodines des ,trias en ,lorraine4 ,compt4 ,rend4 #aijc 7,april #fth74 ---- 7#ji7 ,sur une fructification de ,lycopodine trouve dans le ,trias4 ,compt4 ,rend4 tome ,,cxlviii4 p4 #bei4 ,fontaine1 ,w4 ,m4 7#hc7 ,contributions to the knowledge of the ,older ,mesozoic ,flora of ,virginia4 ,monographs ,u4 ,s4 ,geol4 ,surv4 ,vol4 ,,vi4 ---- 7#hi7 ,the ,potomac or younger ,mesozoic ,flora of ,virginia4 ,u4 ,s4 ,geol4 ,surv4 ,monographs1 ,,vi4 ---- 7#jj7 ,see ,ward1 ,l4 ,f4 ---- 7#je7 ,see ,ward1 ,l4 ,f4 ,fontaine1 ,w4 ,m4 and ,i4 ,c4 ,white4 7#hj7 ,the ,permian or ,upper-,carboniferous ,flora of ,w4 ,virginia and ,pennsylvania4 ,second ,geol4 ,surv4 ,report of ,progress4 ,forbes1 ,e4 7#ea7 ,note on fossil leaves represented in ,plates ,,ii4-,,iv4 in the ,duke of ,argyll's paper on ,tertiary ,leaf-beds in the ,isle of ,mull4 ,quart4 ,journ4 ,geol4 ,soc4 ,vol4 ,,vii4 p4 #ajc4 ---- 7#ec7 ,on the fossils of the ,yellow ,sandstone of the ,south of ,ireland4 ,british ,assoc4 ,rep4 ,london1 #ahec1 p4 #dc 7,belfast meeting1 #aheb74 ,ford1 ,s4 ,o4 7#jb7 ,on the anatomy of ,ceratopteris thalictroides ,l41 ,annals ,bot4 vol4 ,,xvi4 p4 #ie4 ---- 7#jc7 ,see ,seward1 ,a4 ,c4 and ,s4 ,o4 ,ford4 ---- 7#jd7 ,the anatomy of ,psilotum triquetrum4 ,annals ,bot4 vol4 ,,xviii4 p4 #ehi4 ---- 7#jf7 ,see ,seward1 ,a4 ,c4 and ,s4 ,o4 ,ford4 ,freeman1 ,w4 ,g4 7#ii7 ,see ,farmer1 ,j4 ,b4 and ,w4 ,g4 ,freeman4 ,fri1 ,a4 and ,e4 ,bayer4 7#ja7 ,studien im ,gebiete der ,bhmischen ,kreideformation4 ,arch4 ,naturwiss4 ,landes4 ,bhmen1 ,bd4 ,,xi4 ,fritel1 ,p4 ,h4 7#jh7 ,sur une espce fossile nouvelle du genre ,salvinia4 ,journ4 ,bot4 ,ann4 ,,xxi4 ,no4 #h1 p4 #aij4 ,fritsch1 ,f4 ,e4 7#je7 ,see ,tansley1 ,a4 ,g4 and ,f4 ,e4 ,fritsch4 ,fritsch1 ,k4 von4 7#ig7 ,pflanzenreste aus ,thringer ,culm ,dachschiefer4 ,zeitsch4 ,naturwiss4 ,bd4 ,,lxx4 ,gardeners' ,chronicle4 7#hb7 ,selaginella grandis n4 sp4 ,vol4 ,,xvii4 p4 #dj 7,july #h74 ,gardner1 ,j4 ,s4 and ,c4 von ,ettingshausen4 7#hb7 ,a monograph of the ,british ,eocene ,flora4 ,vol4 ,i4 ,filices4 ,palaeont4 ,soc4 ,london4 ,geikie1 ,sir ,archibald4 7#jc7 ,text-book of ,geology4 #b vols4 ,london4 ,geinitz1 ,e4 7#gc7 ,versteinerungen aus dem ,brandschiefer der unteren ,dyas von ,weissing bei ,pillaritz in ,sachsen4 ,neues ,jahrb4 ,min4 p4 #fia4 ,geinitz1 ,h4 ,b4 7#gb7 ,fossile ,myriopoden in dem ,rothliegenden bei ,chemnitz4 ,sitzb4 ,naturwiss4 ,ges4 ,isis1 p4 #abh4 ---- 7#gf7 ,ueber rhaetische ,pflanzen- und ,thierreste in den ,argentinischen ,provinzen ,la ,rioja c4 ,palaeontograph4 ,suppl4 iii4 ,germar1 ,e4 ,f4 7#eb7 ,sigillaria ,sternbergi ,mnster1 aus dem bunten ,sandstein4 ,zeit4 deutsch4 ,geol4 ,ges4 p4 #ahc4 ---- 7#dd-ec7 ,die ,versteinerungen des ,steinkohlengebirges von ,wettin und ,lbejn im ,saalkreise4 ,halle4 ,geyler1 ,h4 ,t4 7#gg7 ,ueber fossile ,pflanzen aus der ,juraformation ,japans4 ,palaeont4 vol4 ,,xxiv4 p4 #bba4 ,giesenhagen1 ,c4 7#ij7 ,die ,hymenophyllaceen4 ,flora1 p4 #daa4 ---- 7#ib7 ,ueber ,hygrophile ,farne4 ,flora1 ,bd4 #gf 7,ergnz4 ,band74 ,gilkinet1 ,a4 7#ge7 ,sur quelques plantes de l'tage du poudingue de ,burnot4 ,acad4 ,roy4 ,belg4 #b vol4 ,,xl4 ,no4 #h4 ,goebel1 ,k4 7#ia7 ,pflanzenbiologische ,schilderungen4 ,teil #b4 ,marburg4 ---- 7#je7 ,organography of ,plants4 ,vol4 ,,ii4 7,trans4 by ,j4 ,b4 ,balfour47 ,oxford4 ,goeppert1 ,h4 ,r4 7#da7 ,die ,gattungen der fossilen ,pflanzen4 ,bonn4 ---- 7#cb7 ,fossile ,flora des ,uebergangsgebirges4 ,nov4 ,act4 ,caes4 ,leop4-,carol4 ,vol4 ,,xiv4 7,supplt474 ---- 7#ed7 ,see ,roemer1 ,f4 ,a4 ,goldenberg1 ,f4 7#ee-fb7 ,flora ,saraepontana ,fossilis4 ,saarbrcken4 ,gordon1 ,w4 ,t4 7#jh7 ,on the ,prothallus of ,lepidodendron ,veltheimianum4 ,trans4 ,bot4 ,soc4 ,edinburgh1 vol4 ,,xxiii4 p4 #ccj4 ---- 7#ji7 ,on the structure of a new ,zygopteris4 ,nature4 7,botany at the ,british ,association47 ,vol4 ,,lxxxi4 p4 #ecg4 ,grand',eury1 ,c4 7#ge7 ,see ,renault1 ,b4 and ,c4 ,grand',eury4 ---- 7#jd7 ,sur les graines des ,neuroptrides4 ,compt4 ,rend4 ,,cxxxix4 p4 #ghb4 ---- 7#je7 ,sur les graines trouves attaches au ,pecopteris ,pluckeneti1 ,schlot4 ,compt4 ,rend4 vol4 ,,cxl4 p4 #ibj4 ---- 7#je7 ,sur les graines de ,sphenopteris c4 ,compt4 ,rend4 ,,cxli4 p4 #hab4 ---- 7#jf7 ,sur les graines et inflorescences des ,callipteris4 ,compt4 ,rend4 ,,cxliii4 p4 #ffd4 ---- 7#jh7 ,sur les organes et la mode de vgtation des ,neuroptrides et autres ,ptridospermes4 ,compt4 ,rend4 ,,clxvi4 p4 #abda4 ,gresley1 ,w4 ,s4 7#hi7 ,note on further discoveries of ,stigmaria 78 ficoides7 and their bearing upon the question of the formation of ,coal-,beds4 ,midland ,naturalist1 vol4 ,,xii4 p4 #be4 ,greville1 ,r4 ,k4 7#ca7 ,see ,hooker1 ,w4 ,j4 and ,r4 ,k4 ,greville4 ,grigoriew1 ,n4 7#ih7 ,sur la flore palozoique suprieure recueillie aux environs des villages ,troitskoie et ,longanskoie dans le bassin du ,donetz4 ,bull4 ,com4 ,gol4 ,st4 ,ptersbourg1 tome ,,xvii4 ,gwynne-,vaughan1 ,d4 ,t4 7#ja7 ,observations on the anatomy of solenostelic ferns4 ,annals ,bot4 vol4 ,,xiv4 p4 #ga4 ---- 7#jc7 ,observations c4 ,ibid4 vol4 ,,xvii4 p4 #fhi4 ---- 7#je7 ,on the anatomy of ,archangiopteris ,henryi and other ,marattiaceae4 ,annals ,bot4 vol4 ,,xix4 p4 #bei4 ---- 7#jg-ji7 ,see ,kidston1 ,r4 and ,d4 ,t4 ,gwynne-,vaughan4 ---- 7#jh7 ,on the real nature of the ,tracheae in the ferns4 ,annals ,bot4 vol4 ,,xxii4 p4 #eag4 ---- and ,r4 ,kidston4 7#jh7 ,on the origin of the adaxially curved leaf-trace in the ,filicales4 ,proc4 ,r4 ,soc4 ,edinb4 vol4 ,,xxviii4 pt4 vi4 p4 #dcc4 ,hall1 ,kate ,m4 7#ia7 ,see ,jennings1 ,a4 ,vaughan1 and ,kate ,m4 ,hall4 ,halle1 ,t4 ,g4 7#jg7 ,einige krautartige ,lycopodiaceen ,palozoischen und ,mesozoischen ,alters4 ,arkiv ,bot4 ,bd4 ,,vii4 ,no4 #e4 ,hannig1 ,e4 7#ih7 ,ueber die ,staubgrbchen auf den ,stmmen und ,blattstielen der ,cyathaeaceen und ,marattiaceen4 ,bot4 ,zeit4 p4 #i4 ,harvey-,gibson1 ,r4 ,j4 7#id7 ,contributions towards a knowledge of the anatomy of the genus ,selaginella1 ,spr4 ,annals ,bot4 vol4 ,,viii4 p4 #acc4 ---- 7#if7 ,contributions c4 ,ibid4 vol4 ,x4 p4 #gg4 ---- 7#ig7 ,contributions c4 ,ibid4 vol4 ,,xi4 p4 #abc4 ---- 7#jb7 ,contributions c4 ,ibid4 vol4 ,,xvi4 p4 #ddi4 ,haughton1 ,s4 7#ei7 ,on ,cyclostigma1 a new genus of fossil plants from the ,old ,red ,sandstone of ,kiltorkan1 ,w4 ,kilkenny4 ,journ4 ,roy4 ,dublin ,soc4 vol4 ,,ii4 p4 #djg4 ,hawkshaw1 ,j4 7#db7 ,description of the fossil trees found in the excavations for the ,manchester and ,bolton railway4 ,trans4 ,geol4 ,soc4 #b vol4 ,,vi4 p4 #agc4 ,hayden1 ,h4 ,h4 7#jg7 ,the stratigraphical position of the ,gangamopteris beds of ,kashmir4 ,rec4 ,geol4 ,surv4 ,india1 vol4 ,,xxxvi4 pt4 i4 ,heer1 ,o4 7#ga7 ,fossile ,flora der ,bren ,inseln4 ,flor4 ,foss4 ,arct4 vol4 ,,ii4 ---- 7#gd7 ,die ,kreideflora der ,arctischen ,zone4 ,k4 ,svensk4 ,vetenskaps-,akad4 ,hand4 ,bd4 ,,xii4 ,flor4 ,foss4 ,arct4 vol4 ,,iii4 #ahge4 ---- 7#ge7 ,flora ,fossilis ,arctica1 vol4 ,,iii4 ---- 7#gf7 ,jura-,flora ,ostsibiriens und des ,amurlandes4 ,ibid4 vol4 ,,iv4 ii4 ---- 7#hj7 ,nachtrge zur fossilen ,flora ,grnlands4 ,k4 ,svensk4 ,vetenskaps-,akad4 ,hand4 ,bd4 ,,xviii4 ,flor4 ,foss4 ,arct4 vol4 ,,vi4 #ahhb4 ---- 7#hb7 ,die ,fossile-,flora ,grnlands4 ,flor4 ,foss4 ,arct4 vol4 ,,vi4 ,hegelmaier1 ,f4 7#gb7 ,zur ,morphologie der ,gattung ,lycopodium4 ,bot4 ,zeit4 #ahgb1 p4 #ggc4 ,hick1 ,t4 7#ic7 ,on a new fossil plant from the ,lower ,coal-,measures4 ,journ4 ,linn4 ,soc4 vol4 ,,xxix4 p4 #hf4 ---- 7#ic7 ,supplementary note on a new fossil plant4 ,ibid4 p4 #baf4 ---- 7#if7 ,on ,rachiopteris cylindrica4 ,mem4 ,proc4 ,manchester ,lit4 ,phil4 ,soc4 vol4 ,,xli4 pt4 i4 ,hieronymus1 ,g4 7#jb7 ,selaginellaceae4 ,die ,natrlichen ,pflanzenfamilien4 ,engler and ,prantl1 ,teil ,i4 ,abt4 #d1 p4 #fba4 ,hill1 ,t4 ,g4 7#jj7 ,see ,scott1 ,d4 ,h4 and ,t4 ,g4 ,hill4 ---- 7#jb7 ,see ,farmer1 ,j4 ,b4 and ,t4 ,g4 ,hill4 ---- 7#jd7 ,on the presence of a parichnos in recent plants4 ,annals ,bot4 vol4 ,,xviii4 p4 #fed4 ---- 7#jf7 ,on the presence of a parichnos in recent plants4 ,ibid4 vol4 ,,xx4 p4 #bfg4 ,hofmeister1 ,w4 7#fb7 ,on the germination1 development1 and fructification of the ,higher ,cryptogamia1 and on the fructification of the ,coniferae4 ,ray ,soc4 #ahfb4 ,hollick1 ,a4 7#id7 ,fossil ,salvinias1 including description of a new species4 ,torrey ,bot4 ,club1 vol4 ,,xxi4 ,no4 #f1 p4 #bec4 ---- 7#jd7 ,additions to the ,palaeobotany of the ,cretaceous ,formation on ,long ,island4 ,bull4 ,new ,york ,bot4 ,gard4 vol4 ,,iii4 p4 #djc4 ---- and ,e4 ,c4 ,jeffrey4 7#ji7 ,studies of ,cretaceous coniferous remains from ,kreischerville1 ,new ,york4 ,mem4 ,new ,york ,bot4 ,gard4 vol4 ,,iii4 ,hooker1 ,sir ,j4 ,d4 7#dh7 ,on the vegetation of the ,carboniferous ,period1 as compared with that of the present day4 ,mem4 ,geol4 ,soc4 ,great ,britain1 vol4 ,,ii4 pt4 ii4 p4 #chg4 ---- 7#dh7 ,remarks on the structure and affinities of some ,lepidostrobi4 ,ibid4 p4 #ddj4 ---- 7#ei7 ,stangeria paradoxa4 ,bot4 ,mag4 ,tab4 #eaba4 ,hooker1 ,sir ,w4 ,j4 and ,j4 ,g4 ,baker4 7#fh7 ,synopsis ,filicum4 ,london4 ,hooker1 ,sir ,w4 ,j4 and ,r4 ,k4 ,greville4 7#ca7 ,icones ,filicum4 ,vol4 ,,ii4 ,london4 ,hosius and von der ,marck4 7#hj7 ,die ,flora der ,westflischen ,kreideformation4 ,palaeont4 ,bd4 ,,xxvi4 p4 #abg4 ,hovelacque1 ,m4 7#ib7 ,recherches sur le ,lepidodendron selaginoides1 ,sternb4 ,mm4 ,soc4 ,linn4 ,normandie1 vol4 ,,xvii4 ,hudson1 ,w4 ,h4 7#ib7 ,the ,naturalist in ,la ,plata4 ,london4 ,jack1 ,r4 ,l4 and ,r4 ,etheridge4 7#ib7 ,the geology and palontology of ,queensland and ,new ,guinea4 ,brisbane4 ,jahn1 ,j4 ,j4 7#jc7 ,ueber die tage ,h4 im mittelbhmischen ,devon4 ,verh4 ,reichsanst4 ,wien1 ,no4 #d1 p4 #gc4 ,jeffrey1 ,e4 ,c4 7#ih7 ,the morphology of the central cylinder in vascular plants4 ,brit4 ,assoc4 ,rep4 7,toronto ,meeting71 p4 #hfi4 ---- 7#ih7 ,the ,gametophyte of ,botrychium virginianum4 ,trans4 ,canad4 ,inst4 vol4 ,v4 p4 #bfe4 ---- 7#jj7 ,the morphology of the central cylinder in the ,angiosperms4 ,ibid4 vol4 ,,vi4 p4 #eii4 ---- 7#jc7 ,the structure and development of the stem in the ,pteridophyta and ,gymnosperms4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,cxcv4 p4 #aai4 ---- 7#ji7 ,see ,hollick1 ,a4 and ,e4 ,c4 ,jeffrey4 ,jennings1 ,a4 ,vaughan and ,kate ,m4 ,hall4 7#ia7 ,notes on the structure of ,tmesipteris4 ,proc4 ,r4 ,irish ,acad4 #c vol4 ,,ii4 p4 #a4 ,jones1 ,c4 ,e4 7#je7 ,the morphology and anatomy of the stem of the genus ,lycopodium4 ,trans4 ,linn4 ,soc4 vol4 ,,vii4 p4 #ae4 ,jordan1 ,rose4 7#jc7 ,on some peculiar tyloses in ,cucumis sativus4 ,new ,phytologist1 vol4 ,,ii4 p4 #bjh4 ,karsten1 ,g4 7#ie7 ,morphologische und biologische ,untersuchungen ber einige ,epiphytenformen der ,molukken4 ,ann4 ,jard4 ,buitenzorg1 vol4 ,,xii4 p4 #aag4 ,kidston1 ,r4 7#hb7 ,on the fructification of ,eusphenopteris tenella and ,sphenopteris microcarpa4 ,r4 ,physc4 ,soc4 ,edinb4 vol4 ,,vii4 ---- 7#hc7 ,report on the fossil plants collected by the ,geological ,survey of ,scotland in ,eskdale and ,liddesdale4 ,trans4 ,r4 ,soc4 ,edinburgh1 vol4 ,,xxx4 p4 #eca4 ---- 7#hd7 ,on a new species of ,lycopodites1 ,goldenberg 7,l4 ,stockii71 from the ,calciferous ,sandstone ,series of ,scotland4 ,ann4 ,mag4 ,nat4 ,hist4 #e vol4 ,,xiv4 p4 #aaa4 ---- 7#hd7 ,on the fructification of ,zeilleria 7,sphenopteris7 delicatula1 ,sternb4 sp42 with remarks on ,urnatopteris 7,sphenopteris7 tenella1 ,brongnt41 and ,hymenophyllites 7,sphenopteris7 quadridactylites1 ,gutbier sp4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xl4 p4 #eij4 ---- 7#he7 ,on the relationship of ,ulodendron1 ,lindley and ,hutton1 to ,lepidodendron1 ,sternberg2 ,bothrodendron1 ,lindley and ,hutton2 ,sigillaria1 ,brongniart2 and ,rhytidodendron1 ,boulay4 ,ann4 ,mag4 ,nat4 ,hist4 vol4 ,,xvi4 p4 #abc4 ---- 7#hf7 ,on a new species of ,psilotites from the ,lanarkshire ,coal-field4 ,ann4 ,mag4 ,nat4 ,hist4 #ahhf1 p4 #did4 ---- 7#hf7 ,on the occurrence of ,lycopodites ,vanuxemi1 ,gppert1 in ,britain1 with remarks on its affinities4 ,journ4 ,linn4 ,soc4 vol4 ,,xxi4 p4 #efj4 ---- 7#hf7 ,notes on some fossil plants collected by ,mr ,r4 ,dunlop1 ,airdrie1 from the ,lanarkshire ,coal-field4 ,trans4 ,geol4 ,soc4 ,glasgow1 vol4 ,,viii4 p4 #dg4 ---- 7#hg7 ,on the fructification of some ferns from the ,carboniferous formation4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 ,,xxxiii4 pt4 i4 ---- 7#hh7 ,see ,bennie1 ,j4 and ,r4 ,kidston4 ---- 7#hh7 ,on the fossil flora of the ,radstock series of the ,somerset and ,bristol ,coal-field 7,upper ,coal-,measures74 ,part ,i4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 ,,xxxiii4 pt4 #b4 ---- 7#hh7 ,on the fructification and affinities of ,archaeopteris hibernica1 ,forbes sp4 ,ann4 ,mag4 ,nat4 ,hist4 #f vol4 ,,ii4 ---- 7#hi7 ,on the fossil plants in the ,ravenhead ,collection in the ,free ,library and ,museum1 ,liverpool4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 ,,xxxv4 pt4 ii4 ---- 7#hi7 ,additional notes on some ,british ,carboniferous ,lycopods4 ,ann4 ,mag4 ,nat4 ,hist4 vol4 ,,iv4 p4 #fj4 ---- 7#hi7 ,on some fossil plants from ,teilia quarry1 ,gwaenysgor1 near ,prestatyn1 ,flintshire4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 ,,xxxv4 pt4 ii4 ---- 7#ia7 ,on the fructification of ,sphenophyllum trichomatosum1 ,stern4 from the ,yorkshire ,coal-field4 ,proc4 ,r4 ,soc4 ,edinb4 vol4 ,,xi4 p4 #ef4 ---- 7#ia7 ,on the fructification and internal structure of ,carboniferous ferns in their relation to those of existing genera4 ,trans4 ,geol4 ,soc4 ,glasgow1 vol4 ,,ix4 pt4 i4 ---- 7#ia7 ,on the ,fossil ,flora of the ,staffordshire ,coal-fields4 ,,ii4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 ,,xxxvi4 p4 #fc4 ---- 7#ic7 ,on ,lepidophloios1 and on the ,british species of the genus4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 ,,xxxvii4 pt4 iii4 p4 #ebi4 ---- 7#id7 ,on the various divisions of ,british ,carboniferous rocks as determined by their fossil flora4 ,r4 ,physc4 ,soc4 ,edinb4 vol4 ,,xii4 p4 #ahc4 ---- 7#if7 ,on the ,fossil ,flora of the ,yorkshire ,coal-fields4 ,i4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 ,,xxxviii4 p4 #bjc4 ---- 7#ig7 ,on the ,fossil ,flora of the ,yorkshire ,coal-fields4 ,,ii4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 ,,xxxix4 pt4 i4 p4 #cc4 ---- 7#ja7 ,carboniferous ,lycopods and ,sphenophylls4 ,trans4 ,nat4 ,hist4 ,soc4 ,glasgow1 vol4 ,,vi4 pt4 i4 p4 #be4 ---- 7#ja7 ,the flora of the ,carboniferous ,period4 ,proc4 ,yorks4 ,geol4 ,polyt4 ,soc4 vol4 ,,xiv4 pt4 ii4 ---- 7#jb7 ,the flora c4 ,second ,paper4 ,ibid4 vol4 ,,xiv4 pt4 iii4 p4 #cdd4 ---- 7#jc7 ,the fossil plants of the ,carboniferous rocks of ,canonbie1 ,dumfriesshire1 and of parts of ,cumberland and ,northumberland4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 ,,xl4 pt4 iv4 p4 #gda4 ---- 7#je7 ,on the internal structure of ,sigillaria elegans of ,brongniart's 8,histoire des ,vgtaux ,fossiles40 ,ibid4 vol4 ,,xli4 pt4 iii4 p4 #ecc4 ---- 7#je7 ,on the fructification of ,neuropteris heterophylla4 ,trans4 ,r4 ,soc4 ,london1 vol4 ,,cxcvii4 p4 #a4 ---- 7#jf7 ,on the microsporangia of the ,pteridospermeae1 with remarks on their relationship to existing ,ferns4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,cxcviii4 p4 #dac4 ---- 7#jg7 ,note on a new species of ,lepidodendron from ,pettycur 7,l4 ,pettycurense74 ,proc4 ,r4 ,soc4 ,edinb4 #aijf-jg1 p4 #bjg4 ---- 7#jg7 ,preliminary note on the internal structure of ,sigillaria mammillaris ,brongniart and ,s4 scutellata ,brongniart4 ,ibid4 vol4 ,,xxvii4 p4 #bjc4 ---- 7#jh7 ,on a new species of ,dineuron and of ,botryopteris from ,pettycur1 ,fife4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 ,,xlvi4 pt4 ii4 p4 #cfa4 ---- 7#jh7 ,see ,gwynne-,vaughan1 ,d4 ,t4 and ,r4 ,kidston4 ,kidston1 ,r4 and ,d4 ,t4 ,gwynne-,vaughan4 7#jg7 ,on the fossil ,osmundaceae4 ,pt4 ,i4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 ,,xlv4 pt4 iii4 p4 #gei4 ---- 7#jh7 ,ibid4 pt4 ,,ii4 loc4 cit4 vol4 ,,xlvi4 pt4 ii4 p4 #bac4 ---- 7#ji7 ,ibid4 pt4 ,,iii4 loc4 cit4 vol4 ,,xlvi4 pt4 iii4 p4 #fea4 ,kitchin1 ,f4 ,l4 7#jh7 ,the invertebrate fauna and palaeontological relations of the ,uitenhage series4 ,ann4 ,s4 ,african ,mus4 vol4 ,,vii4 pt4 ii4 ,knowlton1 ,f4 ,h4 7#ih7 ,a catalogue of the ,cretaceous and ,tertiary plants of ,north ,america4 ,bull4 ,u4 ,s4 ,geol4 ,surv4 ,no4 #aeb4 ---- 7#ii7 ,fossil flora of the ,yellowstone ,national ,park4 ,u4 ,s4 ,geol4 ,surv4 ,mem4 ,,xxxiii4 pt4 ii4 ---- 7#jb7 ,report on a small collection of fossil plants from the vicinity of ,porcupine ,butte1 ,montana4 ,bull4 ,torrey ,bot4 ,club1 vol4 ,,xxix4 ,kny1 ,l4 7#ge7 ,die ,entwickelung der ,parkeriaceen dargestellt an ,ceratopteris thalictroides1 ,brongniart4 ,nova ,acta ,k4 ,leop4-,car4 ,deutsch4 ,akad4 ,naturf4 vol4 ,,xxxvii4 ,koehne1 ,w4 7#jd7 ,sigillarienstmme1 ,unterscheidungsmerkmale1 ,arten1 ,geologische ,verbreitung c4 ,abh4 ,k4 ,preuss4 ,geol4 ,landes4 ,n4 ,f41 ,heft ,,xliii4 ,krasser1 ,f4 7#ie7 ,kreidepflanzen von ,lesina4 ,jahrb4 ,k4-,k4 ,geol4 ,reichs4 ,bd4 ,,xlv4 p4 #cg4 ---- 7#if7 ,beitrge zur ,kenntniss der ,fossilen ,kreideflora von ,kunstadt in ,mhren4 ,beit4 ,palont4 ,geol4 sterreich4-,ung4 und des ,orients1 ,bd4 ,x4 ,heft #c4 ---- 7#jj7 ,die von ,w4 ,a4 ,obrutschew in ,china und ,centralasien #ahic-id gesammelten fossilen ,pflanzen4 ,denksch4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 ,,lxx4 ---- 7#jf7 ,ueber die fossile ,kreideflora von ,grnbach in ,niedersterreich4 ,sitzb4 ,k4 ,akad4 ,wiss4 ,wien 7,anz4 iii474 ---- 7#ji7 ,die ,diagnosen der von ,d4 ,stur in der obertriadischen ,flora der ,lunzerschichten als ,marattiaceenarten unterschiedenen ,farne4 ,sitz4 ,kais4 ,akad4 ,wiss4 ,wien1 ,bd4 ,,cxviii4 ,abt4 i4 ,kubart1 ,b4 7#ji7 ,untersuchungen ber die ,flora des ,ostrau-,karwiner ,kohlenbeckens4 ,i4 ,die ,spore von ,spencerites membranaceus n4 sp4 ,denksch4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 ,,lxxxv4 ,khn1 ,r4 7#ij7 ,untersuchungen ber die ,anatomie der ,marattiaceen4 ,flora4 ,kurr1 ,j4 ,g4 7#de7 ,beitrge zur fossilen ,flora der ,juraformation4 ,stuttgart4 ,kurtz1 ,f4 7#id7 ,contribuciones a la ,palaeophytologia ,argentina4 ,revist4 ,mus4 de la ,plata1 vol4 ,,vi4 ,lang1 ,w4 ,h4 7#ii7 ,the prothallus of ,lycopodium clavatum ,l4 ,annals ,bot4 vol4 ,,xiii4 p4 #bgi4 ---- 7#jh7 ,preliminary statement on the morphology of the cone of ,lycopodium cernuum and its bearing on the affinities of ,spencerites4 ,proc4 ,roy4 ,soc4 ,edinb4 vol4 ,,xxviii4 pt4 ,v4 p4 #cef4 ,leclerc du ,schlon4 7#he7 ,recherches sur la dissemination des ,spores dans les ,cryptogames vasculaires4 ,ann4 ,sci4 nat4 #g1 vol4 ,,ii4 p4 #e4 ,leslie1 ,t4 ,n4 7#jf7 ,see ,mellor1 ,e4 ,t4 and ,t4 ,n4 ,leslie4 ,lesquereux1 ,l4 7#gh7 ,contributions to the fossil flora of the ,western ,territories4 ,pt4 ,,ii4 ,the ,tertiary floras4 ,u4 ,s4 ,geol4 ,surv4 ,report4 ,leuthardt1 ,f4 7#jd7 ,die ,keuperflora von ,neuewelt bei ,basel4 ,teil ,,ii4 ,abh4 ,schweiz4 ,pal4 ,ges4 ,bd4 ,,xxxi4 p4 #be4 ,lignier1 ,o4 7#jc7 ,equistales et ,sphnophyllales4 ,leur origine filicinenne commune4 ,bull4 ,soc4 ,linn4 ,normandie #e1 vol4 ,,vii4 p4 #ic4 ---- 7#jh7 ,sur l'origine des ,sphnophylles4 ,bull4 ,soc4 ,bot4 ,france #d1 vol4 ,,viii4 p4 #bgh4 ,lindman1 ,c4 ,a4 ,m4 7#jd7 ,regnellidium novum genus ,marsiliacearum4 ,arkiv ,bot4 ,k4 ,svensk4 ,vetenskaps-,akad4 ,stockholm4 ,lloyd1 ,e4 and ,l4 ,m4 ,underwood4 7#jj7 ,a review of the species of ,lycopodium of ,north ,america4 ,bull4 ,torrey ,bot4 ,club1 vol4 ,,xxvii4 p4 #adg4 ,logan1 ,w4 ,e4 7#db7 ,on the character of the beds of clay immediately below the coal-seams of ,s4 ,wales4 ,trans4 ,geol4 ,soc4 ,london1 vol4 ,,vi4 p4 #dia4 ,lomax1 ,j4 7#ij7 ,see ,cash1 ,w4 and ,j4 ,lomax4 ---- 7#jj7 ,see ,wild1 ,g4 and ,j4 ,lomax4 ---- 7#je7 ,see ,weiss1 ,f4 ,e4 and ,j4 ,lomax4 ,luerssen1 ,c4 7#hi7 ,die ,farnpflanzen4 ,rabenhorst's ,kryptogamen ,flora1 ,bd4 ,,iii4 ,leipzig4 ,lulham1 ,r4 ,b4 ,j4 7#je7 ,see ,tansley1 ,a4 ,g4 and ,r4 ,b4 ,j4 ,lulham4 ,lyon1 ,f4 ,m4 7#ja7 ,a study of the sporangia and gametophytes of ,selaginella apus and ,s4 rupestris4 ,bot4 ,gaz4 vol4 ,,xxxii4 p4 #abe4 ,mc,coy1 ,sir ,f4 7#dg7 ,on the fossil botany and zoology of the rocks associated with the coal of ,australia4 ,ann4 ,mag4 ,nat4 ,hist4 #a1 vol4 ,,xx4 p4 #aea4 ---- 7#fj7 ,a commentary on 8,a communication made by the ,rev4 ,w4 ,b4 ,clarke0 c4 ,trans4 ,r4 ,soc4 ,victoria1 vol4 ,v4 p4 #if4 ---- 7#gd7 ,prodromus of the ,palaeontology of ,victoria4 ,geol4 ,surv4 ,vict41 ,decades ,i-,v4 ,mc,nicol1 ,mary4 7#jh7 ,on ,cavity ,parenchyma and ,tyloses in ,ferns4 ,ann4 ,bot4 vol4 ,,xxii4 p4 #dja4 ,marion1 ,a4 ,f4 7#ij7 ,sur le ,gomphostrobus heterophylla4 ,compt4 ,rend4 p4 #hib4 ,maslen1 ,a4 ,j4 7#ii7 ,the structure of ,lepidostrobus4 ,trans4 ,linn4 ,soc4 vol4 ,v4 p4 #ceg4 ---- 7#jf7 ,see ,scott1 ,d4 ,h4 and ,a4 ,j4 ,maslen4 ,mellor1 ,e4 ,t4 and ,t4 ,n4 ,leslie4 7#jf7 ,on a fossil forest recently exposed in the bed of the ,vaal ,river at ,vereeniging4 ,trans4 ,geol4 ,soc4 ,s4 ,africa1 vol4 ,,ix4 p4 #abe4 ,mettenius1 ,g4 7#fj7 ,beitrge zur ,anatomie der ,cycadeen4 ,abh4 ,k4 ,schs4 ,ges4 ,wiss4 ,bd4 ,,vii4 p4 #efg4 ---- 7#fc7 ,ueber den ,bau von ,angiopteris4 ,abh4 ,k4 ,schs4 ,ges4 ,wiss4 ,bd4 ,,ix4 ,miller1 ,h4 7#eg7 ,the testimony of the rocks4 ,edinburgh4 ,mller1 ,h4 7#jb7 ,bidrag till ,barnholms ,fossila ,flora4 ,pteridofyter4 ,lunds ,univ4 rsskrift1 ,bd4 ,,xxxviii4 ,no4 #e4 ,mohl1 ,h4 von4 7#dj7 ,ueber den ,bau des ,stammes von ,isoetes lacustris4 ,linnaea1 vol4 ,,xiv4 ,morris1 ,j4 7#dj7 ,ex ,prestwich's1 ,j41 ,memoir on the ,geology of ,coalbrook ,dale4 ,trans4 ,geol4 ,soc4 vol4 ,v4 p4 #dac4 ---- 7#de7 ,see ,strzelecki1 ,count4 ---- 7#fc7 ,see ,oldham1 ,t4 and ,j4 ,morris4 ,motelay1 ,l4 and ,vendrys4 7#hb7 ,monographie der ,isoetaceae4 ,actes ,soc4 ,linn4 ,bordeaux1 ,tom4 ,,xxxvi4 p4 #cji4 ,mnster1 ,g4 ,graf zu4 7#db7 ,beitrge zur ,petrefacten-,kunde4 ,heft #e4 ,bayreuth4 ,murchison1 ,r4 ,i41 ,j4 ,buchman1 and ,h4 ,e4 ,strickland4 7#de7 ,outline of the ,geology of the neighbourhood of ,cheltenham4 ,london4 ,murchison1 ,r41 ,e4 de ,verneuil1 and ,count ,a4 ,keyserling4 7#de7 ,gologie de la ,russie d',europe4 ,vol4 ,,ii4 ,london and ,paris4 ,nathorst1 ,a4 ,g4 7#gh7 ,beitrge zur fossilen ,flora ,schwedens4 ,ueber einige ,rhtische ,pflanzen von ,plsj in ,schonen4 ,stuttgart4 ---- 7#gh7 ,om ,floran i ,sknes kolfrande ,bildningar4 ,sver4 ,geol4 ,unders4 ,ser4 ,c4 ---- 7#ij7 ,ueber das angebliche ,vorkommen von ,geschieben des ,hrsandsteins in den norddeutschen ,diluvialablagerungen4 ,arch4 ,ver4 ,freund4 ,nat4 ,mecklenb41 ,jahr4 ,,xliv4 ---- 7#jb7 ,zur fossilen ,flora der ,polarlnder4 ,i4 ,zur ,oberdevonischen ,flora der ,bren-,insel4 ,k4 ,svensk4 ,vetenskaps-,akad4 ,hand4 ,bd4 ,,xxxvi4 ,no4 #c4 ---- 7#jb7 ,beitrge zur ,kenntniss ,mesozoischen ,cycadophyten4 ,ibid4 ,bd4 ,,xxxvi4 ,no4 #d4 ---- 7#jd7 ,die ,oberdevonische ,flora des ,ellesmere ,landes4 ,rep4 ,second ,norwegian ,arctic ,exp4 in the ,fram 7#ahih-jb71 ,no4 #a4 ---- 7#jd7 ,sur la flore fossile antarctique4 ,compt4 ,rend4 7,june #f47 ---- 7#jf7 ,om ,ngra ,ginkgovxter frn ,kolgrufvorna vid ,stabbarp i ,skne4 ,lunds ,univ4 rsskrift1 ,n4,f4 ,bd4 ,,ii4 ,no4 #h4 ---- 7#jf7 ,bemerkungen ber ,clathropteris meniscoides1 ,brongn41 und ,rhizomopteris cruciata1 ,nath4 ,k4 ,svensk4 ,vetenskaps-,akad4 ,hand4 ,bd4 ,,xli4 ,no4 #b4 ---- 7#jf7 ,ueber ,dictyophyllum und ,camptopteris spiralis4 ,ibid4 ,no4 #e4 ---- 7#jg7 ,ueber die ,anwendung von ,kollodium-,abdrcken bei der ,untersuchung fossiler ,pflanzen4 ,arkiv ,bot41 ,stockholm1 ,bd4 ,,vii4 ,no4 #d4 ---- 7#jg7 ,ueber ,thaumatopteris ,schenki4 ,k4 ,svensk4 ,vetenskaps-,akad4 ,hand4 ,bd4 ,,xlii4 ,no4 #c4 ---- 7#jh7 ,palobotanisch4 ,mitteilungen1 ,,iii4 ,ibid4 ,bd4 ,,xliii4 ,no4 #c4 ,newberry1 ,j4 ,s4 7#ia7 ,the ,flora of the ,great ,falls ,coal-,field1 ,montana4 ,amer4 ,journ4 ,sci4 vol4 ,,xli4 p4 #aia4 ,newton1 ,r4 ,bullen4 7#ji7 ,fossils from the ,nubian ,sandstone of ,egypt4 ,geol4 ,mag4 vol4 ,,vi4 p4 #ceb4 ,oldham1 ,r4 ,d4 7#ig7 ,on a plant of ,glossopteris with part of the rhizome attached1 and on the structure of ,vertebraria4 ,rec4 ,geol4 ,surv4 ,india1 vol4 ,,xxx4 pt4 i4 p4 #de4 ,oldham1 ,t4 and ,j4 ,morris4 7#fc7 ,fossil ,flora of the ,gondwana system4 ,vol4 ,i4 pt4 i4 ,fossil ,flora of the ,rajmahal series in the ,rajmahal ,hills4 ,mem4 ,geol4 ,surv4 ,india #b1 ,calcutta4 ,oliver1 ,f4 ,w4 7#jb7 ,a vascular ,sporangium4 ,new ,phytologist1 vol4 ,i4 p4 #fj4 ---- 7#jd7 ,on the structure and affinities of ,stephanospermum1 ,brongn41 a genus of fossil ,gymnosperm seeds4 ,trans4 ,linn4 ,soc4 vol4 ,,vi4 pt4 #h4 ,peach1 ,c4 ,w4 7#gh7 ,on the circinate vernation1 fructification1 and varieties of ,sphenopteris affinis and on ,staphylopteris 787 ,peachii of ,etheridge and ,balfour1 a genus of plants new to ,british rocks4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xxxiv4 p4 #aca4 ,pelourde1 ,f4 7#jh7 ,recherches sur la position systmatique des plantes fossiles dont les tiges out t appeles ,psaronius1 ,psaroniocaulon1 ,caulopteris4 ,bull4 ,soc4 bot4 ,france #d1 tome ,,viii4 ---- 7#jh7 ,recherches comparatives sur la structure de la racine chez un certain nombre de ,psaronius4 ,ibid4 p4 #ceb4 ---- 7#ji7 ,recherches comparatives sur la structure des fougres fossiles et vivants4 ,ann4 ,sci4 nat4 vol4 ,x4 p4 #aae4 ---- 7#ji7 ,observations sur un nouveau type de ptiole fossile1 le ,flicheia esnostensis4 ,mm4 ,soc4 d'hist4 nat4 d',autun1 tome ,,xxi4 ,penhallow1 ,d4 ,p4 7#ib7 ,additional notes on ,devonian plants from ,scotland4 ,canadian ,rec4 ,sci4 vol4 ,v4 no4 #a4 ---- 7#jb7 ,osmundites skidegatensis4 ,trans4 ,r4 ,soc4 ,canada #b1 vol4 ,,viii4 sect4 #d4 ,phillips1 ,j4 7#ge7 ,illustrations of the ,geology of ,yorkshire1 pt4 ,i4 ,the ,yorkshire ,coast 7edit4 #c74 ,london4 ,pittman1 ,e4 ,f4 7#ic7 ,see ,david1 ,e4 and ,e4 ,f4 ,pittman4 ,potoni1 ,h4 7#hi7 ,der im ,lichthof der ,kniglichen ,geologischen ,landesanstalt und ,bergakademie aufgestellte ,baumstumpf mit ,wurzel aus dem ,carbon des ,piesberges4 ,jahrb4 ,k4 ,preuss4 ,geol4 ,landes1 p4 #bdf4 ---- 7#ia7 ,bericht4 ,deutsch4 bot4 ,ges4 vol4 ,,ix4 p4 #bef4 ---- 7#ib7 ,ueber einige ,carbonfarne4 ,jahrb4 ,k4 ,preuss4 ,geol4 ,landes4 #ahia4 ---- 7#ib7 ,die den ,wasserspalten physiologischentsprechenden ,organe bei fossilen und recenten ,farnarten4 ,sitz4-,ber4 ,ges4 naturforsch4 ,freunde zu ,berlin4 ,july #ai1 #ahib4 ---- 7#ic7 ,anatomie der beiden 8,male0 auf dem unteren ,wangenpaar und der beiden ,seitennrbchen der ,blattnarbe des ,lepidodendron-,blattpolsters4 ,ber4 deutsch4 ,bot4 ,ges4 ,bd4 ,,xi4 ,heft #e1 p4 #cai4 ---- 7#ic7 ,eine gewhnliche ,art der ,erhaltung von ,stigmaria als ,beweis fr die ,autochthonie von ,carbon-,pflanzen4 ,zeits4 ,deutsch4 ,geol4 ,ges4 ---- 7#ie7 ,die ,beziehung zwischen dem echt-gabeligen und dem fiederigen ,wedel-,aufbau der ,farne4 ,ber4 ,deutsch4 ,bot4 ,ges4 ,bd4 ,,xiii4 ,heft #f4 ---- 7#ii7 ,lehrbuch der ,pflanzenpalaeontologie4 ,berlin4 ---- 7#jj7 ,fossile ,pflanzen aus ,deutsch- und ,portugiesisch-,ost-,afrika4 ,deutsch-,ost-,afrika1 ,bd4 ,,vii4 ---- 7#ja7 ,fossile ,lycopodiaceae und ,selaginellaceae4 ,engler and ,prantl3 ,die natrlichen ,pflanzenfamilien1 ,teil ,i4 ,abt4 ,,iv4 p4 #gae4 ---- 7#ja7 ,die ,silur- und die ,culm-,flora4 ,abh4 ,k4 ,preuss4 ,geol4 ,landes4 ,heft ,,xxxvi4 ---- 7#jb7 ,ueber die fossilen ,filicales c4 ,engler and ,prantl3 ,die natrlichen ,pflanzenfamilien1 ,teil ,i4 ,abt4 ,,iv4 p4 #dgc4 ---- 7#jc7 ,zur ,physiologie und ,morphologie der fossilen ,farn-,aphlebien4 ,ber4 ,deutsch4 ,bot4 ,ges4 ,bd4 ,,xxi4 ,heft #c4 ---- 7#jd7 ,abbildungen und ,beschreibungen fossilen ,pflanzen-,reste der ,palaeozoischen und ,mesozoischen ,formationen4 ,lief4 ,,ii4 ,k4 ,preuss4 ,geol4 ,landes- und ,bergakad4 ---- 7#je7 ,ibid4 ,lief4 ,,iii4 ---- 7#jf7 ,ibid4 ,lief4 ,,iii4 ---- 7#jg7 ,abbildungen und ,beschreibungen c4 ,lief4 ,v4 ,prantl1 ,k4 7#ha7 ,untersuchungen zur ,morphologie der ,gefsskryptogamen4 ,heft ,,ii4 ,leipzig4 ---- 7#jb7 ,see ,engler1 ,a4 and ,k4 ,prantl4 ,pritzel1 ,e4 7#jb7 ,lycopodiales4 ,engler and ,prantl3 ,die natrlichen ,pflanzenfamilien1 ,teil ,i4 ,abt4 ,,iv4 p4 #efc4 ,raciborski1 ,m4 7#ia7 ,ueber die ,osmundaceen und ,schizaeaceen der ,juraformation4 ,engler's ,bot4 ,jahrb4 vol4 ,,xiii4 p4 #a4 ,reid1 ,c4 7#ii7 ,the ,origin of the ,british ,flora4 ,london4 ,reinecke1 ,f4 7#ig7 ,die ,flora der ,samoa-,inseln4 ,engler's ,bot4 ,jahrb4 ,bd4 ,,xxiii4 p4 #bcg4 ,renault1 ,b4 7#fi7 tude sur quelques vgtaux silicifis des environs d',autun4 ,ann4 ,sci4 nat4 #e1 vol4 ,,xii4 p4 #afa4 ---- 7#gf7 tude du genre ,botryopteris4 ,ann4 ,sci4 nat4 #f1 vol4 ,i4 p4 #bbj4 ---- 7#gf7 tude du genre ,myelopteris4 ,mm4 ,acad4 ,sci4 l',instit4 ,france1 ,tome ,,xxii4 ---- 7#gi7 ,structure compare de quelques tiges de la ,flore ,carbonifre4 ,nouv4 ,arch4 ,mus4 ,paris4 ---- 7#ha7 tude sur les ,stigmaria4 ,ann4 ,sci4 ,gol4 tome ,,xii4 ---- 7#ij7 ,sur une nouvelle ,lycopodiace houillre 7,lycopodiopsis ,derbyi74 ,compt4 ,rend41 ,april #ad4 ,renault1 ,b4 and ,c4 ,grand',eury4 7#ge7 ,recherches sur les vgtaux silicifis d',autun4 ,mm4 ,acad4 ,paris1 vol4 ,,xxii4 ,renault1 ,b4 and ,a4 ,roche4 7#ig7 ,sur une nouveau ,diploxyle4 ,bull4 ,soc4 d'hist4 nat4 d',autun4 ,renier1 ,a4 7#jh7 ,origine ramale des cicatrices ,ulodendroides du ,bothrodendron punctatum1 ,lind4 et ,hutt4 ,compt4 ,rend41 ,june #bi4 ,reuss1 ,a4 ,e4 7#df7 ,die ,versteinerungen der ,bhmischen ,kreideformation4 ,stuttgart1 #ahde-df4 ,rhode1 ,j4 ,g4 7#bj7 ,beitrge zur ,pflanzenkunde der ,vorwelt4 ,breslau4 ,richter1 ,p4 ,b4 7#jf7 ,beitrge zur ,flora der unteren ,kreide ,quedlinburgs4 ,teil ,i4 ,die ,gattung ,hausmannia1 ,dunker1 und einige seltenere ,pflanzenarten4 ,leipzig4 ,richter1 ,r4 7#ef7 ,see ,unger1 ,f4 and ,r4 ,richter4 ,roche1 ,a4 7#ig7 ,see ,renault1 ,b4 and ,a4 ,roche4 ,roehl1 ,major von4 7#fi7 ,fossile ,flora der ,steinkohlen ,formation ,westphalens4 ,palaeont4 ,bd4 ,,xviii4 p4 #a4 ,roemer1 ,f4 ,a4 7#ed7 ,beitrge zur geologischen ,kenntniss des nordwestlichen ,harzgebirges4 ,palaeont4 ,bd4 ,,iii4 ,royle1 ,j4 ,f4 7#cc7 ,illustrations of the ,botany and other branches of natural history of the ,himalayan ,mountains4 ,london1 #ahcc-ci4 ,rudolph1 ,k4 7#je7 ,psaronien und ,marattiaceen4 ,denksch4 ,kais4 ,akad4 ,wiss4 ,wien1 ,bd4 ,,lxxviii4 ,sadebeck1 ,h4 7#jb7 ,see ,engler1 ,a4 and ,k4 ,prantl4 ,salfeld1 ,h4 7#jg7 ,fossile ,landpflanzen der ,rt4- und ,juraformation ,sdwestdeutschlands4 ,palaeont4 ,bd4 ,,liv4 ---- 7#ji7 ,beitrge zur ,kenntniss jurassischer ,pflanzenreste aus ,norddeutschland4 ,palaeont4 ,bd4 ,,lvi4 ,salter1 ,j4 ,w4 7#eh7 ,on some remains of terrestrial plants in the ,old ,red ,sandstone of ,caithness4 ,quart4 ,journ4 ,geol4 ,soc4 ,proc4 vol4 ,,xiv4 p4 #gg4 ,saporta1 le ,marquis de4 7#hh7 ,dernires adjonctions la flore fossile d',aix-en-,provence4 ,ann4 ,sci4 nat4 #g1 vol4 ,,vii4 ---- 7#id7 ,flore fossile du ,portugal4 ,direct4 ,trav4 ,gol4 ,portugal4 ,lisbon4 ,saxelby1 ,e4 ,m4 7#jh7 ,the origin of the roots in ,lycopodium ,selago4 ,annals ,bot4 vol4 ,,xxii4 p4 #ba4 ,schenck1 ,h4 7#ic7 ,beitrge zur ,biologie und ,anatomie der ,lianen4 ,th4 ,,ii4 ,jena4 ,schenk1 ,a4 7#ga7 ,beitrge zur ,flora der ,vorwelt4 ,die ,flora der ,nordwestdeutschen ,wealdenformation4 ,palaeont4 ,bd4 ,,xix4 p4 #bjc4 ---- 7#gf7 ,zur ,flora der ,nordwestdeutschen ,wealdenformation4 ,palaeont4 ,bd4 ,,xxviii4 p4 #aeg4 ---- 7#he7 ,die whrend der ,reise des ,grafen ,bela ,szchenyi in ,china gesammelten fossilen ,pflanzen4 ,palaeont4 ,bd4 ,,xxxi4 p4 #afe4 ---- 7#hg7 ,fossile ,pflanzen aus der ,albourskette4 ,bibl4 bot4 7,uhlworm und ,haenlein71 ,heft ,,vi4 ,schmalhausen1 ,j4 7#gg7 ,die ,pflanzenreste aus der ,ursa-,stufe im ,fluss-,geschiebe des ,ogur in ,ost-,sibirien4 ,bull4 ,acad4 ,imp4 ,sci4 ,st ,petersburg4 ,tome ,,xxii4 p4 #bgh4 ---- 7#id7 ,ueber ,devonische ,pflanzen aus dem ,donetz-,becken4 ,mm4 ,com4 ,gol4 vol4 ,,viii4 ,st ,petersburg4 ,schuster1 ,j4 7#jh7 ,zur ,kenntniss der ,flora der ,saarbrcker ,schichten und des pflzischen ,oberrotliegenden4 ,geognost4 ,jahresheft1 ,,xx4 #aijg4 ,scott1 ,d4 ,h4 7#if7 ,an introduction to structural botany4 ,pt4 ,,ii4 ,london4 ---- 7#ig7 ,on the structure and affinities of fossil plants from the ,palaeozoic rocks4 ,on ,cheirostrobus1 a new type of fossil cone from the ,lower ,carboniferous strata 7,calciferous ,sandstone series74 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,clxxxix4 p4 #a4 ---- 7#ih7 ,on the structure and affinities c4 ,,ii4 ,on ,spencerites1 a new genus of ,lycopodiaceous cones from the ,coal-,measures founded on the ,lepidodendron ,spenceri of ,williamson4 ,ibid4 vol4 ,,clxxxix4 p4 #hc4 ---- 7#jj7 ,studies in fossil botany4 ,london4 ---- 7#ja7 ,on the structure and affinities c4 ,,iv4 ,the seed-like fructification of ,lepidocarpon1 a genus of ,lycopodiaceous cones from the ,carboniferous formation4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,cxciv4 p4 #bia4 ---- 7#jb7 ,the ,old ,wood and the ,new4 ,new ,phytologist1 vol4 ,i4 p4 #be4 ---- 7#jd7 ,germinating spores in a fossil fern ,sporangium4 ,ibid4 vol4 ,,iii4 p4 #ah4 ---- 7#jd7 ,on the occurrence of ,sigillariopsis in the ,lower ,coal-,measures of ,britain4 ,annals ,bot4 vol4 ,,xviii4 p4 #eai4 ---- 7#je7 ,on the structure and affinities c4 v4 ,on a new type of ,sphenophyllaceous cone 7,sphenophyllum fertile7 from the ,lower ,coal-,measures4 ,phil ,trans4 ,r4 ,soc4 vol4 ,,cxcviii4 p4 #ag4 ---- 7#je7 ,what were the ,carboniferous ferns8 ,journ4 ,r4 ,micr4 ,soc4 p4 #acg4 ---- 7#je7 ,the ,sporangia of ,stauropteris oldhamia4 ,new ,phyt4 vol4 ,,iv4 p4 #aad4 ---- 7#jf7 ,on the structure of some ,carboniferous ferns4 ,journ4 ,r4 ,micr4 ,soc4 p4 #eah4 ---- 7#jf7 ,the occurrence of germinating spores in ,stauropteris oldhamia4 ,new ,phyt4 vol4 ,v4 p4 #agj4 ---- 7#jf7 ,the structure of ,lepidodendron obovatum1 ,sternberg4 ,annals ,bot4 vol4 ,,xx4 p4 #cag4 ---- 7#jg7 ,the present position of ,palaeozoic botany4 ,progressus ,rei ,botanicae1 ,bd4 ,i4 p4 #aci4 ---- 7#jh7 ,studies in fossil botany 7edit4 ,,ii74 ,vol4 ,i4 ,london4 ---- 7#ji7 ,ibid4 ,vol4 ,,ii4 ---- 7#ji7 ,dr ,paul ,bertrand on the ,zygopterideae4 ,new ,phyt4 vol4 ,,viii4 p4 #bff4 ,scott1 ,d4 ,h4 and ,t4 ,g4 ,hill4 7#jj7 ,the structure of ,isoetes ,hystrix4 ,annals ,bot4 vol4 ,,xiv4 p4 #dac4 ,scott1 ,d4 ,h4 and ,a4 ,j4 ,maslen4 7#jf7 ,on the structure of ,trigonocarpon olivaeforme4 ,ann4 ,bot4 vol4 ,,xx4 p4 #aji4 ,scott1 ,j4 7#gd7 ,notes on the tree ferns of ,british ,sikkim4 ,trans4 ,linn4 ,soc4 vol4 ,,xxx4 p4 #a4 ,scott1 ,rina4 7#jf7 ,on the megaspore of ,lepidostrobus foliaceus4 ,new ,phyt4 vol4 ,v4 p4 #aaf4 ---- 7#jh7 ,on ,bensonites fusiformis1 sp4 nov41 a fossil associated with ,stauropteris burntislandica1 ,p4 ,bertrand1 and on the sporangia of the latter4 ,annals ,bot4 vol4 ,,xxii4 p4 #fhc4 ,sellards1 ,e4 ,h4 7#jj7 ,a new genus of ferns from the ,permian of ,kansas4 ,kansas ,univ4 ,quart4 vol4 ,,ix4 ---- 7#ja7 ,permian plants4 ,taeniopteris of the ,permian of ,kansas4 ,ibid4 vol4 ,x4 no4 #a4 ,seward1 ,a4 ,c4 7#hh7 ,on a specimen of ,cyclopteris 7,brongniart74 ,geol4 ,mag4 vol4 ,v4 p4 #cdd4 ---- 7#ij7 ,notes on ,lomatophloios macrolepidotus 7,gold474 ,proc4 ,camb4 ,phil4 ,soc4 vol4 ,,vii4 pt4 ii4 ---- 7#ij7 ,specific variation in ,sigillarieae4 ,geol4 ,mag4 vol4 ,,vii4 p4 #bac4 ---- 7#ia7 ,on an erect tree stump with roots1 from the coal of ,piesberg near ,osnabrck4 ,ibid4 vol4 ,,viii4 ---- 7#ib7 ,fossil plants as tests of climate4 ,london4 ---- 7#id7 ,coal3 its structure and formation4 ,sci4 ,progr4 vol4 ,,ii4 pp4 #cee-dca4 ---- 7#ii7 ,notes on the ,binney collection of ,coal-,measure plants4 ,proc4 ,phil4 ,soc4 ,camb4 vol4 ,x4 p4 #acg4 ---- 7#ii7 ,on the structure and affinities of ,matonia pectinata1 ,r4 ,br4 with notes on the geological history of the ,matonineae4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,cxci4 p4 #aga4 ---- 7#jj7 ,catalogue of the ,mesozoic plants in the ,department of ,geology1 ,british ,museum4 ,the ,jurassic ,flora4 ,i4 ,the ,yorkshire ,coast4 ,london4 ---- 7#jc7 ,fossil floras of ,cape ,colony4 ,ann4 ,s4 ,african ,museum1 vol4 ,,iv4 pt4 i4 ---- 7#jd7 ,the ,jurassic ,flora4 ,,ii4 ,liassic and ,oolitic floras of ,england4 ,cat4 ,mesoz4 ,plants1 ,british ,museum4 ,london4 ---- 7#jd7 ,on a collection of ,jurassic plants from ,victoria4 ,rec4 ,geol4 ,surv4 ,victoria1 vol4 ,i4 pt4 iii4 ---- 7#jd7 ,presidential address4 ,report of the #gcrd meeting of the ,brit4 ,assoc4 7,southport7 p4 #hbd4 ---- 7#jf7 ,the anatomy of ,lepidodendron aculeatum1 ,sternberg4 ,annals ,bot4 vol4 ,,xx4 p4 #cga4 ---- 7#jg7 ,fossil plants from ,egypt4 ,geol4 ,mag4 vol4 ,,iv4 ,v p4 #bec4 ---- 7#jg7 ,on a collection of ,permo-,carboniferous plants from the ,st ,lucia 7,somkale7 coalfield1 ,zululand1 and from the ,newcastle district1 ,natal4 ,trans4 ,geol4 ,soc4 ,s4 ,africa1 vol4 ,x4 p4 #fe4 ---- 7#jg7 ,notes on fossil plants from ,south ,africa4 ,geol4 ,mag4 vol4 ,,iv4 p4 #dha4 ---- 7#jg7 ,jurassic ,plants from ,caucasia and ,turkestan4 ,mm4 ,com4 ,gol4 ,st ,ptersbourg1 ,livr4 #ch4 ---- 7#jg7 ,permo-,carboniferous ,plants from ,kashmir4 ,rec4 ,geol4 ,surv4 ,india1 vol4 ,,xxxvi4 pt4 i4 ---- 7#jh7 ,on a collection of fossil plants from ,south ,africa4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,lxiv4 p4 #hc4 ---- 7#ji7 ,fossil plants from the ,witteberg series of ,cape ,colony4 ,geol4 ,mag4 vol4 ,,vi4 p4 #dhb4 ,seward1 ,a4 ,c4 and ,e4 ,dale4 7#ja7 ,on the structure and affinities of ,dipteris1 with notes on the geological history of the ,dipteridinae4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,cxciv4 p4 #dhg4 ,seward1 ,a4 ,c4 and ,s4 ,o4 ,ford4 7#jc7 ,the anatomy of ,todea1 with notes on the geological history and affinities of the ,osmundaceae4 ,trans4 ,linn4 ,soc4 vol4 ,,vi4 pt4 v4 ---- 7#jf7 ,the ,araucarieae1 recent and extinct4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,cxcviii4 p4 #cje4 ,seward1 ,a4 ,c4 and ,j4 ,gowan4 7#jj7 ,the ,maidenhair ,tree4 7,ginkgo biloba1 ,l47 ,ann4 ,bot4 vol4 ,,xiv4 p4 #aji4 ,seward1 ,a4 ,c4 and ,a4 ,w4 ,hill4 7#jj7 ,on the structure and affinities of a ,lepidodendroid stem from the ,calciferous ,sandstone of ,dalmeny1 ,scotland4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 ,,xxxix4 pt4 iv4 p4 #ijg4 ,seward1 ,a4 ,c4 and ,t4 ,n4 ,leslie4 7#jh7 ,permo-,carboniferous plants from ,vereeniging4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,lxiv4 p4 #aji4 ,seward1 ,a4 ,c4 and ,a4 ,smith ,woodward4 7#je7 ,permo-,carboniferous ,plants and ,vertebrates from ,kashmir4 ,mem4 ,geol4 ,surv4 ,india1 vol4 ,v4 ,mem4 #b4 ,shattock1 ,s4 ,g4 7#hh7 ,on the scars occurring on the stem of ,dammara robusta1 ,moore4 ,journ4 ,linn4 ,soc4 vol4 ,,xxix4 p4 #dda4 ,shove1 ,rosamund4 7#jj7 ,on the structure of the stem of ,angiopteris erecta4 ,annals ,bot4 vol4 ,,xiv4 ,smith1 ,g4 ,o4 and ,d4 ,white4 7#je7 ,the geology of the ,perry basin in ,south ,eastern ,maine4 ,u4 ,s4 ,geol4 ,surv4 ,no4 #ce4 ,sollas1 ,igerna ,b4 ,j4 7#ja7 ,fossils in the ,oxford ,museum4 ,on the structure and affinities of the ,rhaetic plant ,naiadita4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,lvii4 p4 #cjg4 ,solms-,laubach1 ,h4 ,graf zu4 7#hc7 ,zur ,geschichte der ,scolecopteris1 ,zenker4 ,nachr4 ,k4 ,ges4 ,wise4 ,univ4 ,gttingen1 p4 #bf4 ---- 7#ib7 ,ueber die in den ,kalksteinen des ,kulm von ,gltzisch-,falkenberg in ,schlesien erhaltenen ,structurbietenden ,pflanzenreste4 ,bot4 ,zeit4 p4 #di4 ---- 7#id7 ,ueber ,stigmariopsis1 ,grand',eury4 ,palaeont4 ,abh4 7,dames and ,kayser7 ,n4 ,f4 ,bd4 ,,ii4 ,jena4 ---- 7#if7 ,ueber die seinerzeit von ,unger beschriebenen ,strukturbietenden ,pflanzenreste des ,unterculm von ,saalfeld in ,thringen4 ,abh4 ,k4 ,preuss4 ,geol4 ,landes4 ,heft ,,xxiii4 ---- 7#ii7 ,ueber das ,genus ,pleuromeia4 ,bot4 ,zeit4 p4 #bbg4 ---- 7#ii7 ,beitrge zur ,geologie und ,palaeontologie von ,sdamerika4 ,neues ,jahrb4 ,min41 ,beilageband ,,xii4 p4 #eic4 ---- 7#jb7 ,isoetes lacustris1 seine ,verzweigung und sein ,vorkommen in den ,seen des ,schwarzwaldes und der ,vogesen4 ,bot4 ,zeit4 p4 #agi4 ---- 7#jd7 ,ueber die ,schicksale der als ,psaronius brasiliensis beschriebenen ,fossilreste unserer ,museen4 ,festsch4 ,p4 ,ascherson's ,siebzigstem ,geburtstage4 ,berlin4 ---- 7#jf7 ,die ,bedeutung der ,palaeophytologie fr die systematische ,botanik4 ,mitt4 ,philo-math4 ,ges4 ,elsass-,loth4 ,bd4 ,,iii4 p4 #cec4 ,spieker1 ,t4 7#ec7 ,zur ,sigillaria ,sternbergi ,mnster1 des bunten ,sandsteins zu ,bernburg4 ,zeits4 ,gesammt4 ,naturw4 ,bd4 ,,ii4 ,halle4 ,sprengel1 ,a4 7#bh7 ,commentatio de ,psarolithis4 ,halle4 ,spruce1 ,r4 7#jh7 ,notes of a botanist on the ,amazon and ,andes 7,edited by ,a4 ,r4 ,wallace74 ,london4 ,staub1 ,m4 7#hg7 ,die ,aquitanische ,flora des ,zsilthales im comitate ,hunyad4 ,mitt4 ,jahrb4 ,k4 ,ungar4 ,geol4 ,anst4 ,bd4 ,,vii4 ,heft vi4 ,stenzel1 ,c4 ,g4 7#ed7 ,ueber die ,staarsteine4 ,nova ,acta ,leop4 ,carol4 ,bd4 ,,xxiv4 ---- 7#hf7 ,rhizodendron ,oppoliense1 ,gpp4 ,jahresber4 ,schles4 ,ges4 ,vaterl4 ,cultur4 ,ergnzungsheft ,,lxiii4 ---- 7#hi7 ,die ,gattung ,tubicaulis4 ,bibl4 ,bot4 ,heft ,,xii4 ---- 7#ig7 ,verkieselte ,farne von ,kamenz in ,sachsen4 ,mitt4 ,k4 ,mineralog4 ,geol4 und prhistorisch4 ,mus4 ,dresden4 ,heft ,,xiii4 ---- 7#jf7 ,die ,psaronien1 ,beobachtungen und ,betrachtungen4 ,beit4 ,palont4 ,geol4 st4-,ung4 ,bd4 ,,xix4 ,sterzel1 ,j4 ,t4 7#gh7 ,ueber ,palaeojulus dyadicus ,geinitz und ,scolecopteris elegans ,zenker4 ,zeitsch4 ,deutsch4 ,geol4 ,ges4 p4 #dag4 ---- 7#hj7 ,ueber ,scolecopteris elegans ,zenker und andere fossile ,reste4 ,zeitschr4 ,deutsch4 ,geol4 ,ges4 ---- 7#hf7 ,die ,flora des ,rothliegenden im ,plauenschen ,grunde4 ,abh4 ,k4 ,schs4 ,ges4 ,wiss4 ,bd4 ,,xix4 ---- 7#hf7 ,neue ,beitrag zur ,kenntniss von ,dicksonites ,pluckeneti ,brongn4 sp4 ,zeitschr4 ,deutsch4 ,geol4 ,ges4 p4 #ggc4 ---- 7#if7 ,gruppe verkieselten ,araucariten ,stmme4 ,ber4 ,naturwiss4 ,ges4 ,chemnitz1 #ahif-ii4 ---- 7#if7 ,see ,weber1 ,o4 and ,j4 ,t4 ,sterzel4 ,stiehler1 ,a4 ,w4 7#eh7 ,beitrge zur ,kenntniss der vorweltlichen ,flora des ,kreidegebirges im ,harze4 ,palaeont4 ,bd4 ,v4 ---- 7#ei7 ,zu ,pleuromeia4 ,zeit4 ,gesammt4 ,nat4 ,halle1 ,bd4 ,,iii4 p4 #aij4 ,stokey1 ,a4 ,g4 7#jg7 ,the roots of ,lycopodium pithyoides4 ,bot4 ,gaz4 vol4 ,,xliv4 p4 #eg4 ---- 7#ji7 ,the anatomy of ,isoetes4 ,bot4 ,gaz4 vol4 ,,xlvii4 p4 #caa4 ,stopes1 ,marie ,c4 7#jf7 ,a new fern from the ,coal-,measures3 ,tubicaulis ,sutcliffii1 spec4 nov4 ,mem4 ,proc4 ,manch4 ,lit4 ,phil4 ,soc4 vol4 ,l4 ,strasburger1 ,e4 7#gc7 ,einige ,bemerkungen ber ,lycopodiaceen4 ,bot4 ,zeit4 p4 #ha4 ---- 7#gd7 ,ueber ,scolecopteris elegans1 ,zenk4 ,jen4 ,zeitsch4 ,naturwiss4 vol4 ,,viii4 p4 #hh4 ,strzelecki1 ,count4 7#de7 ,physical description of ,new ,south ,wales c4 ,london4 ,stur1 ,d4 7#ha7 ,die ,silur-,flora der tage ,h-h in ,bhmen4 ,sitzb4 ,akad4 ,wiss4 ,wien1 #a ,abth4 ,bd4 ,,lxxxiv4 p4 #ccj4 ---- 7#hd7 ,zur ,morphologie und ,systematik der ,culm- und ,carbonfarne4 ,sitzb4 ,akad4 ,wiss4 ,wien1 ,bd4 ,,lxxxviii4 ---- 7#he7 ,die ,carbon-,flora der ,schatzlarer ,schichten4 ,abh4 ,k4 ,k4 ,geol4 ,reichs4 ,bd4 ,,xi4 ,abth4 ,i4 ,sykes1 ,m4 ,gladys4 7#jh7 ,the anatomy and morphology of ,tmesipteris4 ,annals ,bot4 vol4 ,,xxii4 p4 #fc4 ---- 7#jh7 ,note on an abnormality found in ,psilotum triquetrum4 ,ibid4 vol4 ,,xxii4 p4 #ebe4 ---- 7#jh7 ,notes on the morphology of the ,sporangium-bearing organs of the ,lycopodiaceae4 ,new ,phyt4 vol4 ,,vii4 p4 #da4 ---- 7#ji7 ,note on the ,sporophyll of ,lycopodium inundatum4 ,ibid4 vol4 ,,viii4 p4 #adc4 ,szajnocha1 ,l4 7#hh7 ,ueber fossile ,pflanzenreste aus ,cacheuta in der ,argentinischen ,republik4 ,sitzb4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 ,,xcvii4 ,abth4 ,i4 p4 #bai4 ---- 7#ia7 ,ueber einige ,carbone ,pflanzenreste aus der ,argentinischen ,republik4 ,sitzb4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 ,c4 ,abth4 ,i4 p4 #bjc4 ,tansley1 ,a4 ,g4 7#jh7 ,lectures on the evolution of the filicinean vascular system4 7,reprinted from the ,new ,phytologist47 ,cambridge4 ---- and ,edith ,chick4 7#ja7 ,notes on the conducting tissue-system in ,bryophyta4 ,annals ,bot4 vol4 ,,xv4 p4 #a4 ---- and ,f4 ,e4 ,fritsch4 7#je7 ,the flora of the ,ceylon littoral4 ,new ,phyt4 vol4 ,,iv4 p4 #a4 ---- and ,r4 ,b4 ,j4 ,lulham4 7#je7 ,a study of the vascular system of ,matonia pectinata4 ,annals ,bot4 vol4 ,,xix4 p4 #dge4 ,thiselton-,dyer1 ,sir ,w4 ,t4 7#je7 ,cycas ,micholitzii1 ,dyer4 ,gard4 ,chron4 ,aug4 #ai1 p4 #adb4 ,thoday1 ,d4 7#jf7 ,on a suggestion of heterospory in ,sphenophyllum ,dawsoni4 ,new ,phyt4 vol4 ,v4 p4 #ia4 ,thomas1 ,a4 ,p4 ,w4 7#jb7 ,the affinity of ,tmesipteris with the ,sphenophyllales4 ,proc4 ,r4 ,soc4 vol4 ,,lxix4 p4 #cdc4 ,thomas1 ,ethel ,n4 7#je7 ,some points in the anatomy of ,acrostichum aureum4 ,new ,phyt4 vol4 ,,iv4 p4 #age4 ,thomas1 ,h4 ,h4 7#jh7 ,see ,arber1 ,e4 ,a4 ,n4 and ,h4 ,h4 ,thomas4 ,thompson1 ,d',arcy ,w4 7#hj7 ,notes on ,ulodendron and ,halonia4 ,edinb4 ,geol4 ,soc4 ,trautschold1 ,h4 7#fj7 ,see ,auerbach1 ,j4 and ,h4 ,trautschold4 ,treub1 ,m4 7#hd-ij7 tudes sur les ,lycopodiaces4 ,ann4 ,jard4 ,bot4 ,buitenzorg1 vol4 ,,iv4 ,v4 ,,vii4 ,,viii4 ,underwood1 ,l4 ,e4 7#jj7 ,see ,lloyd1 ,e4 and ,l4 ,m4 ,underwood4 ---- 7#jg7 ,a preliminary review of the ,north ,american ,gleicheniaceae4 ,bull4 ,torrey ,bot4 ,club1 vol4 ,,xxxiv4 p4 #bdc4 ,unger1 ,f4 and ,r4 ,richter4 7#ef7 ,beitrag zur ,palontologie des ,thringer ,waldes4 ,denksch4 ,wien4 ,akad4 ,bd4 ,,xi4 ,velenovsk1 ,j4 7#he7 ,die ,gymnospermen der bhmischen ,kreideformation4 ,prag4 ---- 7#hh7 ,die ,farne der bhmischen ,kreideformation4 ,prag4 ,vines1 ,s4 7#hh7 ,on the systematic position of ,isoetes1 ,l4 ,annals ,bot4 vol4 ,,ii4 pp4 #aag1 #bbc4 ,wanklyn1 ,a4 7#fi7 ,description of some new species of fossil ferns from the ,bournemouth leaf-beds4 ,ann4 ,mag4 ,nat4 ,hist4 vol4 ,,iii4 p4 #aj4 ,ward1 ,l4 ,f4 7#ii7 ,the ,cretaceous ,formation of the ,black ,hills as indicated by the fossil plants4 ,u4 ,s4 ,geol4 ,surv41 #aith ,ann4 ,rep4 pl4 ,,ii4 ---- 7#jj7 ,status of the ,mesozoic ,floras of the ,united ,states1 ,i4 ,u4 ,s4 ,geol4 ,surv41 #bjth1 ,ann4 ,rep4 ---- 7#jd7 ,palaeozoic seed-plants4 ,science1 ,aug4 #bf1 p4 #bgi4 ---- 7#je7 ,status of the ,mesozoic ,floras of the ,united ,states1 ,,ii4 ,u4 ,s4 ,geol4 ,surv4 ,monographs1 vol4 ,,xlviii4 ,watson1 ,d4 ,m4 ,s4 7#jf7 ,on a 8fern0 synangium from the ,lower ,coal-,measures of ,shore1 ,lancashire4 ,journ4 ,r4 ,micr4 ,soc4 p4 #a4 ---- 7#jg7 ,on a confusion of two species 7,lepidodendron ,harcourtii1 ,witham1 and ,l4 ,hickii1 sp4 nov47 under ,lepidodendron ,harcourtii1 ,with4 in ,williamson's ,,xix4 ,memoir1 with a description of ,l4 ,hickii sp4 nov4 ,mem4 ,proc4 ,manch4 ,lit4 ,phil4 ,soc4 vol4 ,,li4 ---- 7#jh7 ,on the ,ulodendron ,scar4 ,ibid4 vol4 ,,lii4 ---- 7#jh7 ,the cone of ,bothrodendron mundum4 ,ibid4 vol4 ,,lii4 ---- 7#ji7 ,on ,mesostrobus1 a new genus of ,lycopodiaceous cones from the ,lower ,coal-,measures c4 ,annals ,bot4 vol4 ,,xxiii4 p4 #cgi4 ,weber1 ,o4 and ,j4 ,t4 ,sterzel4 7#if7 ,beitrge zur ,kenntniss der ,medulloseae4 ,ber4 ,naturwiss4 ,ges4 ,chemnitz1 #ahic-if4 ,weiss1 ,c4 ,e4 7#fi7 ,fossile ,flora der jngsten ,steinkohlenformation und des ,rothliegenden im ,saar-,rhein-,gebiete4 ,bonn1 #ahfi-gb4 ---- 7#gj7 ,studien ber ,odontopteriden4 ,zeitsch4 ,deutsch4 ,geol4 ,ges4 ---- 7#gi7 ,bemerkungen zur ,fructification von ,nggerathia4 ,zeitsch4 ,deutsch4 ,geol4 ,ges4 ---- 7#hd7 ,zur ,flora der ltesten ,schichten des ,harzes4 ,jahrb4 ,k4 ,preuss4 ,geol4 ,landes4 ,berlin4 ---- 7#hf7 ,ueber eine ,buntsandstein ,sigillaria und deren nchste ,verwandte4 ,ibid4 #ahhe4 ---- 7#hh7 ,ueber neue ,funde von ,sigillarien in der ,wettiner ,steinkohlengrube4 ,zeitsch4 ,deutsch4 ,geol4 ,ges4 ---- 7#hi7 ,beobachtungen an ,sigillarien von ,wettin und ,umgegend4 ,neues ,jahrb4 ,bd4 ,,xli4 p4 #cgf4 ---- and ,j4 ,sterzel4 7#ic7 ,die ,sigillarien der ,preussischen ,steinkohlen und ,rothliegenden ,gebiete4 ,k4 ,preuss4 ,geol4 ,landes4 ,n4,f41 ,heft #b4 ,weiss1 ,f4 ,e4 7#jb7 ,on ,xenophyton radiculosum 7,hick71 and on a ,stigmarian rootlet probably related to ,lepidophloios fuliginosus 7,will474 ,mem4 ,proc4 ,manch4 ,lit4 ,phil4 ,soc4 vol4 ,,xlvi4 pt4 #c4 ---- 7#jc7 ,a biseriate ,halonial branch of ,lepidophloios fuliginosus4 ,trans4 ,linn4 ,soc4 vol4 ,,vii4 pt4 #d4 ---- 7#jd7 ,a probable parasite of ,stigmarian rootlets4 ,new ,phyt4 vol4 ,,iii4 p4 #fc4 ---- 7#jf7 ,on the tyloses of ,rachiopteris corrugata4 ,new ,phyt4 vol4 ,v4 p4 #hb4 ---- 7#jg7 ,the ,parichnos in ,lepidodendraceae4 ,mem4 ,proc4 ,manch4 ,lit4 ,phil4 ,soc4 vol4 ,,li4 pt4 ii4 ---- 7#jh7 ,a ,stigmaria with centripetal wood4 ,annals ,bot4 vol4 ,,xxii4 p4 #bba4 ,weiss1 ,f4 ,e4 and ,j4 ,lomax4 7#je7 ,the stem and branches of ,lepidodendron selaginoides4 ,mem4 ,proc4 ,manch4 ,lit4 ,phil4 ,soc4 vol4 ,,xlix4 ,white1 ,d4 7#ic7 ,a new ,taeniopteroid ,fern and its allies4 ,bull4 ,geol4 ,soc4 ,america1 vol4 ,,iv4 p4 #aai4 ---- 7#ie7 ,the ,pottsville series along ,new ,river1 ,west ,virginia4 ,bull4 ,geol4 ,soc4 ,america1 vol4 ,,vi4 p4 #cje4 ---- 7#ih7 ,omphalophloios1 a new ,lepidodendroid type4 ,ibid4 vol4 ,,ix4 p4 #cbi4 ---- 7#ii7 ,fossil flora of the ,lower ,coal-,measures of ,missouri4 ,u4 ,s4 ,geol4 ,surv4 ,mon4 ,,xxxvii4 ---- 7#jb7 ,description of a fossil alga from the ,chemung of ,new ,york4 ,rep4 ,new ,york ,state ,palaeontologist1 #aija4 ---- 7#jd7 ,the seeds of ,aneimites4 ,smithsonian ,miscell4 ,coll4 vol4 ,,xlvii4 pt4 iii4 p4 #cbb4 ---- 7#je7 ,see ,smith1 ,g4 ,o4 and ,d4 ,white4 ---- 7#je7 ,fossil plants of the group ,cycadofilices4 ,smiths4 ,misc4 ,coll4 vol4 ,,xlviii4 pt4 iii4 ---- 7#jg7 ,permo-,carboniferous changes in ,south ,america4 ,journ4 ,geol4 vol4 ,,xv4 p4 #fae4 ---- 7#jg7 ,a remarkable fossil tree trunk from the ,middle ,devonic of ,new ,york4 ,new ,york ,state ,mus4 ,bull4 #ajg4 ,albany4 ---- 7#jh7 ,fossil flora of the ,coal-,measures of ,brazil4 ,rio de ,janeiro4 ,white1 ,i4 ,c4 7#hj7 ,see ,fontaine1 ,w4 ,m4 and ,i4 ,c4 ,white4 ,wickes1 ,w4 ,h4 7#jj7 ,a new ,rhaetic section at ,bristol4 ,proc4 ,geol4 ,assoc4 vol4 ,,xvi4 p4 #dba4 ,wigglesworth1 ,grace4 7#jb7 ,notes on the rhizome of ,matonia pectinata4 ,new ,phyt4 vol4 ,i4 p4 #aeg4 ,wild1 ,g4 and ,j4 ,lomax4 7#jj7 ,a new ,cardiocarpon-bearing strobilus4 ,annals ,bot4 vol4 ,,xiv4 p4 #afj4 ,williamson1 ,w4 ,c4 7#gb7 ,on the organization of the fossil plants of the ,coal-,measures4 ,,iii4 ,lycopodiaceae4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,clxii4 p4 #bhc4 ---- 7#gf7 ,ibid4 pt4 vii4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,clxvi4 p4 #a4 ---- 7#gg7 ,ibid4 pt4 viii4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,clxvii4 p4 #bac4 ---- 7#hc7 ,presidential address4 ,brit4 ,assoc4 ---- 7#hg7 ,note on ,lepidodendron ,harcourtii and ,l4 fuliginosum4 ,proc4 ,r4 ,soc4 vol4 ,,xlii4 p4 #f4 ---- 7#ib7 ,sigillaria and ,stigmaria4 ,nat4 ,science1 p4 #bad4 ---- 7#ic7 ,on the organization c4 pt4 xix4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,clxxxiv4 p4 #a4 ---- 7#ic7 ,general morphological and histological index to the author's collective memoirs on the fossil plants of the ,coal-,measures1 pt4 ii4 ,mem4 ,proc4 ,manch4 ,lit4 ,phil4 ,soc4 #g vol4 ,,vii4 ---- 7#ie7 ,on the light thrown upon the question of growth and development of the ,carboniferous arborescent ,lepidodendra by a study of the details of their organisation4 ,ibid4 vol4 ,,ix4 p4 #ca4 ---- 7#if7 ,reminiscences of a ,yorkshire ,naturalist4 7,edited by ,mrs ,crawford ,williamson47 ,london4 ,woodward1 ,a4 ,smith4 7#je7 ,see ,seward1 ,a4 ,c4 and ,a4 ,smith ,woodward4 ,worsdell1 ,w4 ,c4 7#ie7 ,on transfusion-tissue2 its origin and function in the leaves of ,gymnospermous plants4 ,trans4 ,linn4 ,soc4 vol4 ,v4 p4 #cja4 ,wnsch1 ,e4 ,a4 7#fg7 ,discovery of erect stems of fossil trees in trappean ash in ,arran4 ,trans4 ,geol4 ,soc4 ,glasgow1 vol4 ,,ii4 p4 #ig4 ,yabe1 ,h4 7#je7 ,mesozoic plants from ,korea4 ,journ4 ,colt4 ,sci4 ,imp4 ,univ4 ,japan1 vol4 ,,xx4 ,yapp1 ,r4 ,h4 7#jb7 ,two ,malayan #8,myrmecophilous' ferns1 ,polypodium 7,lecanopteris7 carnosum 7,blume71 and ,p4 sinuosum4 ,annals ,bot4 vol4 ,,xvi4 p4 #ahe4 ---- 7#jh7 ,sketches of vegetation at home and abroad4 ,,iv4 ,wicken ,fen4 ,new ,phyt4 vol4 ,,vii4 p4 #fa4 ,yokoyama1 ,m4 7#hi7 ,jurassic plants from ,kaga1 ,hida1 and ,echizen4 ,journ4 ,coll4 ,sci4 ,imp4 ,univ4 ,japan1 vol4 ,,iii4 ---- 7#jf7 ,mesozoic plants from ,china4 ,ibid4 vol4 ,,xxi4 ,zalessky1 ,m4 7#jd7 ,vgtaux fossiles du ,terrain ,carbonifre du ,bassin du ,donetz4 ,mm4 ,com4 ,gol4 ,st ,ptersbourg4 ,livr4 ,,xiii4 ---- 7#jg7 ,sur la prsence de ,mixoneura neuropteroides1 ,gpp4 avec ,neuropteris ,scheuchzeri1 ,hoffmann1 et ,n4 rarinervis1 ,bunbury c4 ,bull4 ,com4 ,gol4 ,st ,ptersbourg1 tome ,,xxvi4 ---- 7#jh7 ,vgtaux fossiles du ,terrain ,carbonifre du bassin du ,donetz4 ,,ii4 tude sur la structure anatomique d'un ,lepidostrobus4 ,mm4 ,com4 ,gol41 ,livr4 ,,xlvi4 ,zeiller1 ,r4 7#gi7 ,note sur quelques fossiles du terrain permien de la ,corrze4 ,bull4 ,soc4 ,gol4 ,france1 tome ,,viii4 p4 #aif4 ---- 7#gi7 ,note sur le genre ,mariopteris4 ,bull4 ,soc4 ,gol4 ,france #c1 tome ,,vii4 p4 #ib4 ---- 7#hc7 ,fructifications de ,fougres houillres4 ,ann4 ,sci4 nat4 #f1 vol4 ,,xvi4 ---- 7#hd7 ,cnes de fructification des ,sigillaires4 ,ibid4 vol4 ,,xix4 p4 #bef4 ---- 7#he7 ,sur les affinits du genre ,laccopteris4 ,bull4 ,soc4 ,bot4 ,france1 tome ,,xxxii4 p4 #ba4 ---- 7#hf7 ,prsentation d'une brochure de ,m4 ,kidston sur les ,ulodendron et observations sur les genus ,ulodendron et ,bothrodendron4 ,bull4 ,soc4 ,gol4 ,france #c1 tome ,,xiv4 p4 #afh4 ---- 7#hi7 ,sur les variations de formes du ,sigillaria ,brardi1 ,brongn4 ,ibid4 #c1 tome ,,xvii4 p4 #fjc4 ---- 7#ij7 ,bassin ,houiller et ,permien d',autun et d'pinac4 tudes des ,gtes ,min4 ,france4 ---- 7#id7 ,notes sur la flore des ,couches ,permiennes de ,trienbach 7,alsace74 ,bull4 ,soc4 ,geol4 ,france #c1 tome ,,xxii4 p4 #afc4 ---- 7#ie7 ,note sur la flore fossile des ,gisements houillers de ,rio ,grande do ,sul4 ,bull4 ,soc4 ,gol4 ,france #c1 tome ,,xxiii4 p4 #fja4 ---- 7#ig7 ,observations sur quelques fougres des ,dpts houillers d',asie ,mineure4 ,bull4 ,soc4 ,bot4 ,france #c1 tome ,,xliv4 p4 #aie4 ---- 7#ig7 ,the reference of the genus ,vertebraria4 7,translation from the ,compt4 ,rend1 tome ,,cxxii4 p4 #gdd47 ,rec4 ,geol4 ,surv4 ,india1 vol4 ,,xxx4 pt4 i4 ---- 7#ig7 ,les ,provinces botaniques de la fin des temps primaires4 ,rev4 ,gn4 ,sci4 7,jan4 #ae74 ---- 7#ig7 ,revue des travaux de palontologie vgtale4 ,rev4 ,gn4 ,bot4 tome ,,ix4 ---- 7#ih7 ,sur un ,lepidodendron silicifi du ,brsil4 ,compt4 ,rend4 7,july #be74 ---- 7#ih7 ,sur la dcouverte1 par ,m4 ,amalitzky1 de ,glossopteris dans le ,permien suprieur de ,russie4 ,bull4 ,soc4 ,bot4 ,france1 tome ,,xlv4 p4 #cib4 ---- 7#ih7 ,contribution l'tude de la flore ptridologique des schistes permiens de ,lodve4 ,bull4 ,mus4 de ,marseille1 tome ,i4 ,fasc4 ,,ii4 p4 #i4 ---- 7#ii7 tude sur la flore fossile du ,bassin houiller d',hracle4 ,mm4 ,soc4 ,gol4 ,france 7,palont471 ,mm4 #ba4 ---- 7#jj7 ,sur une ,slaginelle du terrain houiller de ,blanzy4 ,compt4 ,rend4 vol4 ,,cxxv4 p4 #ajgg4 ---- 7#jj7 lments de ,palobotanique4 ,paris4 ---- 7#jb7 ,observations sur quelques plantes fossiles des ,lower ,gondwanas4 ,mem4 ,geol4 ,surv4 ,india ,new ,series1 vol4 ,,ii4 ---- 7#jc7 ,flore fossile des ,gtes de ,charbon du ,tonkin4 tudes des ,gtes ,min4 ,france4 ,paris4 ---- 7#jc7 ,revue des travaux de ,palontologie vgtale4 ,rev4 ,gn4 ,bot4 vol4 ,,xv4 ---- 7#je7 ,une nouvelle classe de ,gymnospermes3 les ,ptridospermes4 ,rev4 ,gn4 ,sci4 p4 #gah4 ---- 7#jf7 ,bassin houiller et ,permien de ,blanzy et du ,creusot 7,fasc4 ii74 tudes ,gtes ,min4 ,france4 ---- 7#ji7 ,observations sur le ,lepidostrobus ,brownii4 ,compt4 ,rend4 vol4 ,,cxlviii4 p4 #hij4 ---- 7#ji7 ,revue des travaux de ,palontologie vgtale 7#aija-jf74 ,rev4 ,gn4 ,bot41 vols4 ,,xxi1 ,,xxii4 ,zenker1 ,j4 ,c4 7#cg7 ,scolecopteris elegans ,zenk4 ,ein neues fossiles ,farrngewchs mit ,fructificationen4 ,linnaea1 vol4 ,,xi4 p4 #eji4 ,,index ,the ,index includes the names of ,authors and plants mentioned in this volume4 ,no references are1 however1 given to the following ,authors1 whose names occur too frequently to render special reference of use to the reader3 ,a4 ,brongniart1 ,r4 ,kidston1 ,a4 ,g4 ,nathorst1 ,h4 ,potoni1 ,b4 ,renault1 ,d4 ,h4 ,scott1 ,h4 ,graf zu ,solms-,laubach1 ,d4 ,stur1 ,w4 ,c4 ,williamson1 ,k4 ,zeiller4 ,abies pectinata1 #bag ,acrostichites ,goeppertianus1 #cdj1 #cda ,a4 linnaeaefolius1 #cdj ,a4 rhombifolius1 #cdj ,a4 tenuifolius1 #ccb ,a4 ,williamsonis1 #cci ,acrostichum1 #dii1 #ejj ,a4 aureum1 #cji1 #cgi ,a4 7,lomariopsis7 sorbifolium1 #cja ,adiantites1 #cgf1 #efj ,a4 antiquus1 #cgf1 #cgg ,a4 lindsayoides1 #cgf1 #cgg ,a4 ,sewardi1 #cgg ,adiantum pedatum1 #cjj ,a4 apalophyllum1 #chj ,agathis1 #aca1 #aie ,a4 australis1 #ie ,alethopteris1 #dhe1 #eaf1 #eeg1 #egb-egf ,a4 ,grandini1 #egd ,a4 lonchitica1 #cii1 #eec1 #egd1 #ege ,a4 ,roesserti1 #cdf ,a4 ,serlii1 #ege1 #egf ,alloiopteris1 #dgj1 #egi ,a4 ,essinghii1 #ece ,alsophila1 #bie ,a4 excelsa1 #bid ,a4 tahitiensis1 #cji ,alsophilina1 #cgb ,amalitzky1 ,w41 #dih1 #eac ,anachoropteris ,decaisnii1 #dfb ,anachoropteroides1 #dee ,andrae1 ,k4 ,j41 #cij ,androstrobus1 #hh ,aneimia1 #bhg1 #bhh1 #cdf1 #cej ,a4 flexuosa1 #bhi ,a4 phyllitidis1 #bhi ,a4 rotundifolia1 #bhh1 #cjg ,aneimites1 #cdf ,angiopteridium1 #dhe ,a4 californicum1 #dji ,angiopteris1 #agb1 #cag1 #dag1 #dbe1 #dee1 #ebg ,a4 evecta1 #bhc1 #cag-cai ,a4 ,richthofeni1 #dji ,ankyropteris1 #cfe1 #dej-dfb1 #dfe ,a4 bibractensis1 #dec-def1 #dga ,a4 corrugata1 #dcf1 #dec1 #dee-dfb1 #dga ,a4 scandens1 #dej-deb1 #def1 #dfa1 #dfb1 #dga ,anomopteris ,mougeotii1 #cbi ,a4 ,schlectendalii1 #cbi ,anomozamites1 #dhi ,antrophyum1 #dii ,aphlebia #ebe-ebi1 #ecc-ecf1 #eee ,a4 crispa1 #ebf1 #ebh ,a4 ,germari1 #ebf ,aphyllum cristatum1 #abg ,araucaria1 #be ,a4 ,balansae1 #cf ,a4 excelsa1 #cf ,a4 imbricata1 #ic1 #baa ,araucarieae1 #dd1 #bge ,araucarites ,cordai1 #ahg ,a4 gracilis1 #hd ,arber1 ,e4 ,a4 ,n41 #agh1 #cie1 #dbj1 #dcc1 #dig1 #ejj1 #ejg1 #ejh1 #eab1 #eac ,arber1 ,e4 ,a4 ,n4 and ,h4 ,h4 ,thomas1 #bad1 #bbb ,arberia1 #eaf ,a4 minasica1 #eaf ,arberia sp41 #eag ,archaeopterideae1 #efe ,archaeopteris1 #ae1 #ebf1 #efj-efe ,a4 archetypus1 #efc-efe ,a4 ,dawsoni1 #efd ,a4 fimbriata1 #efc-efe ,a4 fissilis1 #efc1 #efd ,a4 gaspiensis1 #efc ,a4 hibernica1 #efa-efe ,a4 ,jacksoni1 #efc ,a4 ,roemeriana1 #efc ,a4 ,tschermaki1 #efd ,archaeosigillaria1 #gh1 #bfg1 #bfh ,a4 primaeva1 #bja1 #bfh ,archangiopteris1 #cah1 #cai ,arctopodium insigne1 #def ,artis1 ,f4 ,t41 #abg1 #aif1 #bbi1 #bca1 #dbb ,aspidiaria1 #abd1 #abg1 #abh ,aspidites caudatus1 #djd ,asplenites1 #ehj ,a4 macrocarpus1 #cdf ,a4 ottonis1 #cdf ,asplenium ,johnstrupi1 #cfi ,a4 multilineatum1 #cja ,a4 nebbense1 #cdd ,a4 nidus1 #dhe ,a4 resectum1 #cjj ,a4 whitbiense1 #cdd ,asterochlaena duplex1 #ddh ,a4 laxa1 #dfb1 #dga1 #dgb ,a4 ramosa1 #dga ,asterotheca1 #cih1 #dji1 #dbf1 #egf ,a4 ,sternbergii1 #cih1 #djj ,aulacopteris1 #efg ,azolla1 #aib1 #bgd1 #dge ,baiera1 #cjg1 #cij ,baily1 ,w4 ,h41 #dfi1 #ecg1 #efj1 #efb ,baker1 ,j4 ,g41 #cc1 #cjg ,balfour1 ,j4 ,h41 #aia ,barrois1 ,c41 #ajc ,bartholin1 ,c4 ,t41 #cib ,bates1 ,h4 ,w41 #cji ,bennettitales1 #cif ,bennie1 ,j41 #g ,bennie1 ,j4 and ,r4 ,kidston1 #he ,benson1 ,margaret1 #bgg1 #ecb ,bensonites fusiformis1 #dfi ,bergeria1 #abd1 #abf1 #abg1 #agd1 #aha ,bernouillia1 #dji1 #daj1 #eda ,berridge1 ,e4 ,m41 #aid ,berry1 ,e4 ,w41 #edc ,bertrand1 ,c4 ,e41 #afc1 #bac1 #bad1 #bbb1 #bge1 #bgg ,bertrand1 ,c4 ,e4 and ,f4 ,cornaille1 #caf ,bertrand1 ,p41 #dcb1 #dcd1 #dce1 #ddc1 #ddg1 #ddi-deb1 #dfb1 #dfg1 #dfh ,binney1 ,e4 ,w41 #ajc1 #aaj1 #acg1 #aec1 #afd1 #aga1 #ahh1 #bcb1 #bch1 #dfb1 #dfe ,bischof1 -- #fi ,blanckenhorn1 ,m41 #gb1 #ebb1 #ebc ,blechnoxylon talbragarense1 #eji-eaa ,bommer1 ,c41 #dj1 #cec1 #cfa ,boodle1 ,l4 ,a41 #bj1 #ba1 #bd1 #cjd1 #caa1 #dfh ,bothrodendreae1 #bdh-bff ,bothrodendron1 #ge1 #abh1 #acj-acc1 #acg1 #ahh1 #bji1 #bcd1 #bdj1 #bdh-bfh1 #bgf ,b4 kiltorkense1 #beb1 #bee1 #beg-bei ,b4 ,leslei1 #beh ,b4 minutifolium1 #bea-bef1 #bfb ,b4 mundum1 #bef1 #bfb1 #bfc ,b4 punctatum1 #ace1 #bdh1 #bej1 #beb1 #bed1 #bfj ,b4 tenerrimum1 #bfd ,bothrostrobus1 #aib1 #bfb-bfd1 #bgh ,botrychioxylon1 #dei ,botrychium1 #afi1 #dbg1 #dch1 #dei1 #eaj ,b4 ,lunaria1 #cbb ,b4 virginianum1 #cbb ,botryoptereae1 #dcd-ddc ,botryopterideae1 #cbe1 #cfe1 #cge1 #dbg1 #dcb-dgb ,botryopteris1 #dcf-ddc ,botryopteris antiqua1 #dcf1 #ddb1 #ddc1 #dgj1 #dga ,b4 cylindrica1 #dcf1 #dch ,b4 forensis1 #dcg1 #dch1 #ddb-dde1 #dfc1 #dgj ,b4 hirsuta1 #dcf1 #dch ,b4 ramosa1 #dcf1 #dch1 #ddj1 #dda1 #dgj ,boulay1 ,n41 #bea ,bowenia1 #edi ,b4 spectabilis1 #dch ,bower1 ,f4 ,o41 #ac1 #ad1 #ag1 #dd1 #df1 #ec1 #gh1 #aia1 #bfd1 #bfh1 #bhb1 #bhd1 #bif1 #bih1 #cjj1 #cjg1 #cbe ,bowman1 ,j4 ,e41 #bcb ,brabenec1 -- #dgf ,brainea1 #bii ,brittsia1 #dfd ,b4 problematica1 #dfd ,brodie1 ,p4 ,b41 #hb ,brongniart1 ,a4 ,see note1 page #fji ,brown1 ,richard1 #bcb1 #bcc1 #bcg1 #bci ,brown1 ,robert1 #afj1 #aij ,browne1 ,lady ,isabel1 #bfg1 #bfi ,bruchmann1 ,h41 #fd ,bunbury1 ,sir ,charles1 #cdh1 #ceb1 #dha1 #egj1 #egb ,butterworth1 ,j41 #aga1 #dac ,calamites1 #f1 #aa1 #gc1 #bjg1 #bjh ,c4 radiatus1 #aa1 #bfe1 #bef ,calamodendron1 #gc ,calamostachys1 #i ,callipteridium1 #efj ,c4 gigas1 #eeg ,c4 pteridium1 #efj ,callipteris1 #eef-efj ,c4 ,bergeroni1 #eeh ,c4 conferta1 #eeh-efj ,c4 conferta var4 polymorpha1 #eei ,c4 flabellifera1 #efh ,c4 lyratifolia1 #eeg1 #eeh ,calymmatotheca1 #djg1 #eca1 #ecb ,c4 affinis1 #ecb ,c4 ,stangeri1 #eca ,campbell1 ,d4 ,h41 #fh1 #aib1 #cjh ,camptopteridinae1 #che ,camptopteris1 #chi1 #cij ,c4 exilis1 #cha ,c4 lunzensis1 #che ,c4 ,phillipsii1 #chc ,c4 spiralis1 #chb1 #chi1 #cij ,cancellatae1 #bjc ,canna1 #eag ,cannophyllites1 #eag ,cardiocarpon1 #bga ,c4 anomalum1 #bga ,cardiopteris1 #eai1 #ebc-ebe ,c4 frondosa1 #ebc-ebf ,c4 ,hochstetterii var4 franconica1 #ebd ,c4 ,zuberi1 #edj ,carica sp41 #bjb1 #bjc ,carolopteris1 #cfj ,carruthers1 ,w41 #bg1 #acj1 #acg1 #afc1 #aga1 #age-aha1 #bga1 #cci1 #cgd1 #dia1 #ead1 #efb1 #efe ,cash1 ,w4 and ,j4 ,lomax1 #aed ,castilloa1 #aca ,caulopteris1 #cgb1 #dac1 #dba1 #dbb ,c4 anglica1 #dba ,c4 gigantea1 #dbd ,c4 peltigera1 #dai-dbb ,c4 ,saportae1 #dba ,c4 tessellata1 #ij ,cephalotheca1 #bi1 #ecg ,c4 mirabilis1 #ecf1 #ecg ,ceratopteris1 #cjc ,c4 thalictroides1 #big ,ceratozamia1 #efe ,cheirolepis1 #hd ,cheiropteris palmatopedata1 #cjj ,cheirostrobeae1 #ab ,cheirostrobus1 #g-ab1 #ad1 #ae1 #ba1 #bd ,c4 pettycurensis1 #h ,chiropteris1 #dca ,c4 spatulata1 #dca ,c4 ,williamsii1 #dca ,c4 ,zeilleri1 #dcj ,chodat1 ,r41 #bhj1 #bha1 #caf ,chorionopteris gleichenoides1 #dgf ,christ1 ,h41 #bic ,christ1 ,h4 and ,k4 ,giesenhagen1 #cai ,chrysodium lanzaeanum1 #cej1 #cgh ,cladophlebis1 #cdc-cdf1 #egi1 #ehj ,c4 ,albertsii1 #cdd ,c4 ,brownii1 #cdi ,c4 denticulata1 #ccb1 #cce1 #cdj-cdf ,c4 ,dunkeri1 #cdi ,c4 koraiensis1 #cdi ,c4 lobifolia1 #ebi ,c4 ,roesserti1 #cdc ,c4 virginiensis1 #cdj ,clathraria1 #bjc ,c4 ,brardi1 #aih1 #bbd ,clathropteris1 #che-chi ,c4 egyptiaca1 #chh1 #chi ,c4 meniscoides1 #chf1 #chg ,c4 platyphylla1 #chg ,c4 whitbyensis1 #chc ,clepsydropsis1 #ddh-dej ,c4 antiqua1 #ddd1 #ddf1 #ddi ,coenopterideae1 #cfe1 #dcb-dgb1 #ebf ,coniopteris1 #cfg1 #cfh1 #dji ,c4 arguta1 #cgj1 #cga ,c4 hymenophylloides1 #cff-cgj1 #ebh ,c4 lunzensis1 #cfg ,c4 ,murrayana1 #cfg ,c4 quinqueloba1 #cgj ,corda1 ,a4 ,j41 #fh1 #fi1 #aje1 #cdf1 #cdg1 #ced1 #cgc1 #dbb1 #ddc1 #dgf ,corynepteris1 #dfi1 #dgj1 #egh ,c4 coralloides1 #dde ,c4 stellata1 #dfi ,cotta1 ,c4 ,b41 #dab1 #ddc ,coward1 ,k4 ,h41 #bba ,crematopteris1 #ebc ,crpin1 ,f41 #bg1 #ecg1 #efc ,crossotheca1 #cif ,cryptomeria1 #cf ,ctenis ,leckenbyi1 #edi ,ctenopteris1 #edh-eej ,c4 cycadea1 #edh1 #edi ,c4 ,sarrani1 #eda1 #edi ,ctenozamites1 #edh ,cyathea1 #bie1 #cac ,c4 dealbata1 #cdd ,c4 ,imrayana1 #cac ,cyathea sinuata1 #bie ,c4 spinulosa1 #bid ,cyatheaceae1 #bid-bif1 #cfe-cge1 #djc ,cyatheites1 #cff ,cyathocarpus dentatus1 #djd ,cyathotrachus altus1 #cih ,cycadophyta1 #dhd ,cycadopteris1 #edd1 #edf ,cycas1 #acc ,c4 ,micholitzii1 #cjg ,cyclopteris1 #efj1 #efa1 #eff1 #ega-egb ,c4 angustifolia1 #eab ,c4 hibernica1 #efj ,c4 ,roemeriana1 #efc ,cyclostigma1 #bea ,c4 australe1 #bei ,c4 densifolium1 #beg ,c4 ,griffithsi1 #bea1 #bee ,c4 hercynium1 #beg ,c4 kiltorkense1 #bea1 #bee1 #beg ,c4 minutum1 #bea1 #bee ,cyparissidium1 #ci ,cyperus papyrus1 #bcj ,czekanowskia1 #fg ,dacrydium1 #cf ,d4 cupressinum1 #ge ,d4 ,kirkii1 #ge ,dactylotheca1 #cif1 #djd-djf1 #ebg1 #efe1 #egf ,d4 dentata1 #djd ,d4 plumosa1 #cii1 #djj1 #djd-djf ,danaea1 #cba1 #cih ,d4 microphylla1 #daj ,d4 trichomanoides1 #cjj ,danaeites1 #cih1 #dhe ,d4 ,heeri1 #daj ,d4 sarepontanus1 #cih1 #djj ,danaeopsis1 #djg ,d4 ,hughesi1 #dji ,d4 marantacea1 #djh ,d4 ,storrsii1 #cde ,darwin1 ,c41 #ajc1 #cja1 #ead ,davallia1 #bh1 #bic1 #bif1 #cff ,d4 aculeata1 #bii1 #cjj1 #cee1 #ecc ,d4 concinna1 #bid ,dawes1 ,j4 ,s41 #acj1 #acg1 #aec ,dawson1 ,sir ,j4 ,w41 #bf-bi1 #agg1 #beg1 #cdf1 #dgf1 #efc ,debey1 ,m4 ,h4 and ,c4 von ,ettingshausen1 #cee1 #cfj ,dechenia ,roemeriana1 #beg ,dennstaedtiinae1 #bif ,derbyella1 #eaf ,d4 aurita1 #eag ,dichopteris1 #eej-eeb ,d4 lanceolata1 #eea ,d4 visianica1 #eej1 #eea ,dicksonia1 #bic1 #cff1 #cgd ,d4 antarctica1 #dbd ,d4 ,bertervana1 #bie ,dicksonia coniifolia1 #bid ,d4 culcita1 #bid ,d4 ,johnstrupi1 #cfi1 #cgj ,d4 lobifolia1 #ebi ,dicksonites ,pluckeneti1 #cff ,dictophyllum1 #chj-che ,d4 acutilobum1 #cha ,d4 exile1 #cha-chc1 #chf ,d4 ,fuchsi1 #che ,d4 ,nathorsti1 #chc1 #che1 #chg ,d4 ,nilssoni1 #chb ,d4 rugosum1 #chj1 #chc-che ,dictyopteris1 #ega1 #egb ,dictyoxylon1 #bbj ,didymochlaena1 #egd ,didymophyllum ,schollini1 #abd ,didymosorus comptonifolius1 #cee ,diplolabis1 #dcc1 #dcd1 #ddf-ddi1 #dfe ,d4 esnostensis1 #ddg1 #ddh ,d4 forensis1 #ddd-ddf ,diplotmema1 #cea1 #ecj1 #ecc-ecg ,d4 furcatum1 #ebi1 #ecf ,d4 ,zeilleri1 #ece1 #ecf ,dipteridinae1 #bih1 #chj-cid ,dipteris1 #cjh1 #cab1 #cha1 #cij1 #cic1 #cid1 #ecc ,d4 bifurcata1 #bih ,d4 conjugata1 #big1 #bih1 #chd ,d4 ,lobbiana1 #bih ,d4 quinquefurcata1 #big ,d4 ,wallichii1 #big1 #bih ,discopteris1 #djb1 #djc ,d4 cristata1 #djb1 #djc ,d4 karwinensis1 #djb1 #djc ,d4 ,rallii1 #cdj1 #ejj ,d4 ,schumanni1 #djb ,drymoglossum carnosum1 #cjd ,drynaria fascia1 #daa ,dunker1 ,w41 #cij ,eichwald1 ,e4 d'1 #cbf1 #cbi ,endogenites1 #dab ,engler1 ,a41 #bhb ,equisetales1 #aj1 #ae ,etapteris1 #dce1 #dfe ,e4 ,scotti1 #ddd1 #dfb1 #dfc ,etheridge1 ,r41 #eje1 #eaj ,ettingshausen1 ,c4 von1 #be1 #cfd1 #cgf1 #ecg1 #edb ,eufilicineae1 #bhc-caf ,euphorbia1 #aif1 #bca ,euphorbites vulgaris1 #aif1 #aih ,eu-,sigillariae1 #bjc ,eusphenopteris tenella1 #djg ,farmer1 ,j4 ,b4 and ,t4 ,g4 ,hill1 #cah1 #dah ,favularia1 #aih1 #bjc ,fe1 ,a4 ,l4 ,a41 #cja ,feistmantel1 ,c41 #hd1 #abf1 #acf1 #acg1 #cdf1 #cgb1 #dji1 #dcj1 #dhi1 #eac1 #edj1 #eda ,feistmantel1 ,o41 #dcj ,felix1 ,j41 #dch ,ferns1 fossil1 #cbd-dgb ---- recent1 #bhj-cbc ,ficoidites verrucosus1 #bca ,filicales1 #bhj-dgb ,filicites arborescens1 #egg ,f4 cycadea1 #edh ,f4 dubius1 #aha1 #dif ,f4 lineatus1 #ecg ,f4 lonchiticus1 #egd ,f4 meniscoides1 #chf ,f4 ,miltoni1 #cii ,f4 ,nilssoniana1 #dhb ,f4 plumosus1 #djd ,f4 pteridius1 #efj ,fitting1 ,h41 #gb1 #gc ,flemingites1 #aha ,f4 ,pedroanus1 #agg ,fliche1 ,p41 #gc1 #ij1 #ia ,flicheia esnostensis1 #ddh ,fontaine1 ,w4 ,m41 #cdb1 #cdc1 #cde1 #ceb1 #cfb1 #cfc1 #cfh1 #cgh1 #edc ,fontaine1 ,w4 ,m4 and ,i4 ,c4 ,white1 #dbd1 #dhg1 #egj ,fri1 ,a4 and ,e4 ,bayer1 #cge1 #dgd ,fritel1 ,p4 ,h41 #dgf ,fritsch1 ,k4 von1 #ebd ,forbes1 ,e41 #chj1 #efj ,fucoides1 #ebe ,gangamopteris1 #eab-eag ,g4 cyclopteroides1 #ead-eaf ,g4 kashmirensis1 #eaf1 #eag ,gangamopteris flora1 #aha1 #eac ,gardiner1 ,stanley1 #dc ,gardner1 ,j4 ,s41 #hb ,gardner1 ,j4 ,s4 and ,c4 von ,ettingshausen1 #cci1 #cej1 #chj1 #cid ,geinitz1 ,h4 ,b41 #bf1 #gi1 #acj1 #agd1 #bcc1 #djb1 #dia1 #edj1 #efa ,germar1 ,e4 ,f41 #fi1 #bja1 #bfe ,geyler1 ,h4 ,t41 #cgh ,gilkinet1 ,a41 #bh1 #ecg ,ginkgo1 #cjg ,g4 digitata1 #cgf ,gleichenia1 #hc1 #caa1 #cab1 #cea1 #ddf1 #ebf1 #ecc ,g4 circinata1 #bhi ,g4 ,cunninghami1 #cjj ,g4 dicarpa1 #bij1 #caj1 #cea1 #ced ,g4 dichotoma1 #bij1 #bia ,g4 dubia1 #cdd ,g4 hantonensis1 #cee ,g4 linearis1 #bia ,g4 lineata1 #edj ,g4 moniliformis1 #bia ,gleicheniaceae1 #bhh-bia1 #cea-cee ,gleichenites1 #cea ,g4 elegans1 #cec ,g4 gracilis1 #cec ,g4 hantonensis1 #cef ,g4 longipennis1 #ced ,g4 microphyllus1 #cec ,g4 neuropteroides1 #cea ,g4 ,nordenskioldii1 #ced ,g4 ,rostafinskii1 #bij1 #cec ,g4 ,zippei1 #ced1 #cee ,glenopteris1 #ech ,glossopteris1 #cji1 #dif-eab ,g4 angustifolia1 #ejg1 #ejh1 #eji ,g4 angustifolia var4 taeniopteroides1 #ejh ,g4 ,browniana1 #dif-ejg ,g4 conspicua1 #eab ,glossopteris flora1 #aha1 #eac1 #ead ,g4 indica1 #eje-ejh1 #eab ,g4 longifolia1 #dhb ,g4 ,phillipsi1 #dhj ,g4 retifera1 #eaa1 #eab ,g4 ,tatei1 #eab ,goebel1 ,k41 #cja1 #ebf ,goeppert1 ,h4 ,r41 #abd1 #bbh1 #bcc1 #bce1 #cea1 #cff1 #che1 #cih ,goldenberg1 ,f41 #gf1 #gg1 #gi1 #hf1 #hg1 #abf1 #aih1 #bjh1 #bag1 #bca ,gomphostrobus1 #be1 #bf ,gonatosorus ,nathorsti1 #cff ,goniopteris unita1 #cig ,gordon1 ,w4 ,t41 #agg1 #ddg1 #ddh1 #dga ,gradatae1 #bhe1 #bih ,grammatopteris1 #dcd-dcf1 #ddc1 #dga ,g4 ,rigolloti1 #dcd ,grand',eury1 ,c41 #acg1 #bjj1 #bjd1 #bje1 #bbf1 #bcd-bch1 #ceb1 #cff1 #cih1 #dad1 #dbf1 #dfd1 #ecb1 #ecd1 #eee-eeg1 #efe1 #efg1 #egb1 #ege1 #egf ,gresley1 ,w4 ,s41 #bbh ,grigoriew1 ,n41 #ebd ,gunn1 ,marcus1 #cfa1 #cib ,gunnera1 #ebh ,g4 manicata1 #ebg ,gutbier1 ,a4 von1 #ebe1 #egb ,gwynne-,vaughan1 ,d4 ,t41 #aac1 #cad1 #cbg1 #cge1 #dfa ,gymnogramme reniformis1 #cjj ,haliserites ,dechianus1 #bg ,halle1 ,t4 ,g41 #gf-hj1 #hc1 #hg ,halonia1 #abh1 #ace-aci1 #adh1 #aej1 #aec1 #aed ,h4 regularis1 #ada1 #aec ,h4 tortuosa1 #acf ,hapalopteris1 #djf ,harcourt1 ,c4 ,g4 ,v4 ,v41 #afj ,harvey1 ,w4 ,h41 #cjc ,harvey-,gibson1 ,r4 ,j41 #ea1 #ed1 #ee ,haughton1 ,s41 #bea1 #bee ,hausmannia1 #cij-cid ,h4 dichotoma1 #cia1 #cib ,h4 ,forchammeri1 #cib ,h4 ,kohlmanni1 #cgd1 #cib ,h4 ,richteri1 #cic ,h4 ,sewardi1 #cgd1 #cic ,hawkshaw1 ,j41 #bcb1 #bch ,hawlea1 #cih1 #djj1 #dja1 #egf ,h4 ,miltoni1 #cii1 #djj ,h4 pulcherrima1 #cii1 #djj ,hayden1 ,h4 ,h41 #ead ,heer1 ,o41 #aa1 #be1 #hd1 #beg1 #cea1 #ced1 #cee1 #cfh1 #cfi1 #cge1 #djg1 #daj1 #daa1 #dgd ,hegelmaier1 ,f41 #dc ,helminthostachys1 #cbb1 #dcd1 #dcf1 #dch ,hemingway1 ,w41 #gi1 #bec1 #ega1 #egd ,hemitelia capensis1 #cjb1 #cjd1 #ebh ,hemitelites1 #cff ,henry1 ,a41 #cai ,hepaticae1 #cjh ,heterangium1 #gg1 #cea1 #ecb ,hexagonocarpon1 #egb ,hick1 ,t41 #aeg-aei1 #dch ,hill1 ,a4 ,w41 #db1 #afd1 #bhf ,hill1 ,t4 ,g41 #fa1 #fe ,hofmeister1 ,w41 #ef1 #fc ,hollick1 ,a41 #be1 #dgd1 #dge ,hooker1 ,sir ,joseph1 #dj1 #acj1 #bdf1 #cji ,hooker1 ,sir ,j4 and ,e4 ,w4 ,binney1 #ahe ,hooker1 ,sir ,william1 #bia ,hose1 ,c41 #bia ,hostinella1 #bh ,hovelacque1 ,m41 #aaa ,hutton1 ,w41 #bee ,hydropterideae1 #bhj1 #bhd1 #dgc-dhc ,hymenophyllaceae1 #bid1 #cja1 #cfc-cfe1 #dcd1 #dfe ,hymenophyllites1 #cfc ,h4 patentissima1 #cfd ,h4 ,phillipsi1 #cfg ,h4 quadridactylites1 #cfe ,hymenophyllum dilatatum1 #bhi ,h4 tunbridgense1 #bid1 #cjj1 #cae ,h4 waldenburgense1 #cfc ,h4 ,weissi1 #cfd ,h4 ,wilsoni1 #bid ,hymenopteris psilotoides1 #cgh ,inversicatenales1 #dcb ,isoetaceae1 #cc1 #eh-ff ,isoetes1 #cj-cc1 #df1 #eh-fh1 #gb1 #hh-ia1 #ajc1 #age1 #ahd1 #aia1 #bjh1 #bag1 #bdf1 #bfi1 #bgd1 #bgg1 #bgh ,isoetes ,boryana1 #fj ,i4 ,braunii1 #fh ,i4 ,choffati1 #ff ,i4 echinospora1 #eh1 #ei ,i4 hystrix1 #cc1 #fj1 #fa1 #fe1 #ff ,i4 lacustris1 #cc1 #eh1 #ei1 #fa1 #fb1 #ff ,i4 ,scheuzeri1 #fh ,i4 setacea1 #fh ,isoetites1 #fg1 #fh ,i4 ,choffati1 #fg ,i4 crociformis1 #fg ,isoetopsis1 #fh ,i4 subaphylla1 #fh ,jack1 ,r4 ,l4 and ,r4 ,etheridge1 #eji ,jahn1 ,j4 ,j41 #bh ,jamesonia1 #cjd1 #cab ,jeffrey1 ,e4 ,c41 #aac1 #caj1 #cab1 #cae ,jordan1 ,r41 #dfa ,juncus1 #eh ,karsten1 ,g41 #cja ,kaulfussia1 #cba1 #dcd ,kerr1 ,t41 #afd ,kidston1 ,b4 ,see note1 page #fji ,kidston1 ,b4 and ,j4 ,bennie1 #aia ,kidston1 ,b4 and ,d4 ,t4 ,gwynne-,vaughan1 #bfg1 #cad1 #cbf1 #cbi1 #ccd1 #cch1 #cdf1 #cgg1 #dfa1 #dgb ,kidstonia heracleensis1 #cbe1 #cdj ,klukia1 #cdh ,k4 exilis1 #cdg-cdi1 #cgj ,knorr1 ,g4 ,w41 #abd ,knorria1 #abd-abg1 #agd ,k4 imbricata1 #bee ,k4 mirabilis1 #abe ,knowlton1 ,f4 ,h41 #cej1 #chj ,kolbe1 -- #cce ,knig1 ,c41 #bji ,krasser1 ,f41 #aha1 #cfa1 #dji1 #daj1 #dgd1 #eej1 #eeb1 #efc ,kubart1 ,b41 #aie ,kunze1 -- #cjg ,kurr1 ,j4 ,g41 #dca1 #edd ,laccopteris1 #cee-cfa1 #daa ,l4 ,dunkeri1 #cfa ,l4 elegans1 #ceg ,l4 ,goepperti1 #ceg1 #ceh ,l4 ,muensteri1 #cgd ,l4 polypodioides1 #ceh-cfa1 #cgd ,l4 ,woodwardi1 #cfj ,laminaria 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#hh1 #if1 #aid1 #aie1 #bae1 #bea1 #bec1 #bfc1 #dag ,l4 alopecuroides1 #cb1 #hb ,l4 alpinum1 #cb1 #da ,l4 annotinum1 #cb ,l4 arboreum1 #gf ,l4 casuarinoides1 #ce1 #ci ,l4 cernuum1 #ca1 #cg1 #ci1 #da-di1 #ic1 #ahe1 #aid1 #bag ,l4 clavatum1 #cb1 #dj1 #da1 #df ,l4 complanatum1 #hg ,l4 cruentum1 #cb ,l4 ,dalhousianum1 #ce1 #ch1 #db ,l4 densum1 #dj ,l4 dichotomum1 #cd1 #ce1 #da1 #dd1 #df1 #ajf ,l4 elongatum1 #hg ,l4 eryithraeum1 #cf ,l4 falcatum1 #hc ,l4 inundatum1 #cb1 #dc1 #dd ,l4 nummularifolium1 #ce1 #ch ,l4 obscurum1 #ch1 #ci1 #ic ,l4 ,phlegmaria1 #ci1 #dd1 #de1 #gh ,l4 primaevum1 #hf ,l4 rufescens1 #cd-cf ,l4 saururus1 #da1 #db ,l4 selaginoides1 #cc ,l4 ,selago1 #d1 #cb1 #cd1 #dd1 #hg1 #acc1 #bef ,l4 serratum1 #db ,l4 squarrosum1 #cf1 #ch1 #ci ,l4 tetragonum1 #ce1 #ci1 #gf ,l4 verticillatum1 #ci ,l4 volubile1 #ce1 #ci ,lycopsida1 #cab ,lycostrobus1 #hh-ia ,l4 ,scotti1 #hh-ia ,lyginodendron1 #adj1 #bba1 #bgj1 #dfj1 #eaj1 #ecb1 #efe ,lygodium1 #db1 #bhg1 #caa1 #ddf1 #ecc1 #ecd1 #ecg ,l4 dichotomum1 #ccg ,l4 ,kaulfussi1 #cej ,lyon1 ,f4 ,m41 #eg1 #eh ,mc,coy1 ,sir ,f41 #ahj1 #dia1 #ejj1 #eab ,mc,nicol1 ,mary1 #dfa ,macroglossum alidae1 #cba ,macrotaeniopteris1 #dhf ,m4 ,feddeni1 #dhi ,m4 ,wianamattae1 #dhi ,macrozamia corallipes1 #chb ,m4 ,fawcettiae1 #chb ,malaquin1 ,m41 #ajc ,marattia1 #cbj1 #djh1 #dji1 #dag1 #dee1 #dhe1 #ebg ,m4 fraxinea1 #cag1 #cbj1 #ebh ,m4 ,hookeri1 #cej1 #daa ,m4 ,kaulfussii1 #cbj1 #cig1 #dja1 #daa ,marattiaceae1 #caf-cba1 #cea1 #ceb1 #cie1 #daa1 #dcd1 #ddg1 #efe1 #egf ,marattiales1 #caf-cba1 #cie-daa ,marattiopsis1 #djg-dji ,marattiopsis marantacea1 #ceh1 #djh1 #dji ,m4 ,muensteri1 #cbj1 #djh1 #dji ,marion1 ,a4 ,f41 #be1 #bf ,mariopteris1 #cea1 #ecc-ecf ,m4 muricata1 #ecd1 #eec ,marsilia1 #dgc1 #dgg-dgi ,m4 ,andersoni1 #dgd ,m4 cretacea1 #dgd ,m4 ,drummondi1 #dgd ,marsilia elata1 #dgd ,m4 ,nathorsti1 #dgd ,m4 perucensis1 #dgd ,m4 quadrifoliata1 #dgc ,marsiliaceae1 #dgc-dge ,marsilidium1 #dgd ,m4 speciosum1 #dgd ,martin1 ,w41 #bbi ,martius1 ,k4 ,f4 ,p4 von1 #dbj ,maslen1 ,a4 ,j41 #ahg1 #ahi1 #aij ,matonia1 #bia1 #bib1 #bih1 #cjh1 #caf1 #cha1 #dbj1 #ecc ,m4 pectinata1 #bhi-bic1 #cjj1 #caj1 #cad1 #cef1 #ceg1 #cfb1 #cfc1 #chc ,m4 sarmentosa1 #bia1 #caj ,matonidium1 #fc1 #caj1 #cee1 #cei1 #cfa-cfc ,m4 ,althausii1 #cfb1 #cfc ,m4 ,goepperti1 #cfb ,m4 ,wiesneri1 #ceh1 #cfc ,matonineae1 #bia-bic1 #cee-cfc ,medullosa1 #eeh1 #efg ,m4 anglica1 #egd ,megalopteris1 #eji ,megaloxylon1 #cca ,megaphyton1 #dac-dae1 #dbb ,m4 frondosum1 #dbb ,m4 insigne1 #dba ,m4 ,mc,layi1 #dbb ,mellor1 ,e4 ,t4 and ,t4 ,n4 ,leslie1 #bcc ,mertensides1 #ceb ,mesostrobus1 #aie ,metaclepsydropsis1 #ddg-dej ,m4 duplex1 #ddh-dej ,mettenius1 ,g41 #bbc1 #dbd1 #dbe ,miadesmia1 #ib1 #bge-bgi ,m4 membranacea1 #bge1 #bgf ,microcachrys tetragona1 #gf ,microdictyon1 #cfj ,miller1 ,h41 #bg1 #bh1 #ecb ,mixoneura1 #eee ,mixtae1 #bhe ,mohl1 ,h4 von1 #fc ,mohlengraaff1 ,g4 ,a4 ,f41 #eje ,mohria1 #bhg ,mller1 ,h41 #cib1 #dha ,monogramme1 #cjf ,morris1 ,j41 #ahe1 #aia1 #eci ,mnster1 ,g4 ,graf zu1 #bd1 #fg-fi ,muscites falcatus1 #hc ,myeloxylon1 #eef1 #egd ,ngeli1 ,k4 ,w4 von1 #ee ,naiadaceae1 #hb ,naiadea acuminata1 #ha ,n4 lanceolata1 #ha ,n4 petiolata1 #ha ,naiadita1 #hb1 #hc ,n4 lanceolata1 #ha ,naiadites acuminatus1 #ha ,nathorst1 ,a4 ,g4 ,see note1 page #fji ,nathorstia1 #cfa1 #daj1 #daa ,n4 angustifolia1 #daj ,n4 latifolia1 #daj ,nephrodium filix-mas1 #cac ,nerium oleander1 #efg ,neuropteridium1 #eai-ebc1 #ebe ,n4 grandifolium1 #eai1 #ebb ,n4 intermedium1 #eba-ebc ,n4 ,plantianum1 #eba ,n4 validum1 #eai-ebc1 #ebe1 #eei ,n4 ,voltzii1 #ebc ,neuropteris1 #cih1 #eaf1 #ebf1 #ebh1 #eeb1 #eec1 #eef1 #eeg1 #efe-egb1 #egi1 #ehj ,n4 cordata1 var4 angustifolia1 #egj ,n4 cordata1 var4 densineura1 #ebd ,n4 conferta1 #eei ,n4 ,goeppertiana1 #cdj ,n4 ,grangeri1 #efg ,n4 heterophylla1 #cea1 #ece1 #efh ,n4 hirsuta1 #egj ,n4 horrida1 #ega ,n4 macrophylla1 #ece1 #efi ,n4 pseudogigantea1 #efg ,n4 recentior1 #cci ,n4 ,scheuchzeri1 #ece1 #efi-ega ,n4 valida1 #ebj ,newberry1 ,j4 ,s41 #dca ,nilssonia1 #dhe ,nipa1 #cji ,noeggerathia1 #dbh-dca1 #efj ,n4 acuminifissa1 #efc ,n4 flabellata1 #dca ,n4 foliosa1 #dbi ,n4 obovata1 #ead ,noeggerathiopsis1 #bcc1 #eaf ,northampton1 ,marquis of1 #aij ,odontopteris1 #eaf1 #ebf1 #ebh1 #eeb-eeh1 #efj1 #efg1 #ega ,o4 cf4 alpina1 #eee ,o4 ,browni1 #eef ,o4 cycadea1 #edh ,o4 ,fischeri1 #eef ,o4 genuina1 #eef1 #eeg ,o4 jurensis1 #edd ,o4 macrophylla1 #edj ,o4 minor1 #eed1 #eee ,o4 osmundaeformis1 #eed ,o4 ,plantiana1 #eai1 #eba ,o4 ,reichiana1 #eee ,o4 ,wortheni1 #eee ,oldham1 ,r4 ,d41 #dig1 #eja1 #ejc1 #eje1 #eaj ,oldham1 ,t4 and ,j4 ,morris1 #hd ,oleandra1 #cja ,o4 neriiformis1 #dhe1 #dib ,oleandridium1 #dhe1 #dhf ,o4 lentriculiforme1 #dib ,oligocarpia1 #dji ,o4 ,brongniarti1 #ceb1 #cfd ,o4 ,gutbieri1 #ceb ,oliver1 ,f4 ,w41 #dcg1 #ddc1 #ecb ,omphalophloios1 #bfd-bff ,o4 anglicus1 #aig1 #bfd ,oncopteris1 #cgb1 #cgc ,o4 ,nettvalli1 #cgc ,onoclea hebraidica1 #chj ,o4 sensibilis1 #chj ,o4 struthiopteris1 #cjc1 #cdd1 #ejb1 #ejc ,onychiopsis1 #cfi1 #cgg-chj ,o4 elongata1 #cgh ,o4 ,mantelli1 #cgd1 #cgh1 #cgi ,o4 psilotoides1 #cgh ,ophioglossaceae1 #cba-cbc1 #dcd ,ophioglossales1 #dbg-dca ,ophioglossites antiqua1 #dbh ,ophioglossum1 #ab1 #cba1 #dbh ,o4 palmatum1 #cbb ,o4 pendulum1 #cba ,o4 vulgatum1 #cba1 #cbb ,osmunda1 #bfg1 #cda1 #efg ,o4 cinnamomea1 #bhf1 #ccc1 #cci ,o4 ,claytoniana1 #cad1 #cae1 #ccc1 #cch ,o4 lignitum1 #cci ,o4 regalis1 #bhe1 #bhf1 #cca1 #cch1 #cdb ,o4 ,sturii1 #cci ,osmundaceae1 #bhe1 #bhf1 #cjh1 #cad1 #cae1 #cbd-cdf1 #djc1 #dji1 #dcd1 #ddc1 #ddh1 #dfa1 #dgb ,osmundites ,dowkeri1 #cch1 #cci ,o4 ,dunlopi1 #cca-ccd1 #ccg1 #cdf ,o4 ,gibbiana1 #cce1 #cci ,o4 ,kolbei1 #ccd-ccg ,o4 skidegatensis1 #ccg1 #cch ,o4 ,sturii1 #cci ,otopteris cuneata1 #dha ,otozamites ,beani1 #cjg ,ottokaria bengalensis1 #dih ,o4 ovalis1 #dih ,pachyphloeus tetragonus1 #aga ,pachypteris1 #eej1 #eeb ,p4 dalmatica1 #eej ,p4 lanceolata1 #eej ,pachytesta1 #egd1 #ege ,palaeojulus dyadieus1 #dja1 #djb ,palaeopteris1 #efj1 #efa ,p4 hibernica var4 minor1 #efc ,palmatopteris1 #ecc1 #ece1 #ecg ,p4 furcata1 #ecg ,parapecopteris1 #cih ,p4 neuropteroides1 #cih1 #cii ,parkeriaceae1 #big ,parkinson1 ,j41 #aha1 #bca1 #dac1 #ege ,paullinia thalictrifolia1 #cjg ,peach1 ,c4 ,w41 #ecj ,pecopteris1 #bih1 #cih1 #did1 #ecb1 #eda1 #eeg1 #egf-ehj ,p4 abbreviata1 #cii ,p4 arborescens1 #dbb1 #ebi1 #egg1 #egh ,p4 bullatus1 #ceb ,p4 caespitosa1 #cei ,p4 crenifolia1 #cei ,p4 cristata1 #djb ,p4 curtata1 #cci ,p4 cyathea1 #dbb ,p4 dentata1 #cci1 #djd ,p4 denticulata1 #cdc ,p4 exilis1 #cdh ,p4 ,huttoniana1 #cdj ,p4 ligata1 #cei ,p4 ,miltoni1 #cii ,p4 ,phillipsii1 #cdc ,p4 ,pluckeneti1 #dai1 #dbf1 #egf1 #egi ,p4 plumosa1 #cii1 #djd ,p4 polymorpha1 #egi ,p4 recentior1 #cci ,p4 reticulata1 #did ,p4 ,rutimeyeri1 #cdc ,p4 serra1 #djd ,p4 ,sterzeli1 #dai1 #dbf1 #egi ,p4 tenuis1 #cci ,p4 undans1 #cde ,p4 unita1 #cig1 #egi ,p4 whitbiensis1 #cci1 #cdc1 #cdd ,p4 ,williamsonis1 #cci ,p4 ,zippei1 #ced ,pelourde1 ,f41 #ddh ,penhallow1 ,d4 ,p41 #bh1 #gh1 #ccg ,petver1 -- #bca ,phanerosorus1 #bib ,phillips1 ,j41 #fg1 #cdh ,phlebopteris ,phillipsi1 #chc ,p4 polypodioides1 #ceh ,p4 propinqua1 #ceh ,p4 ,woodwardi1 #cfj ,phragmites1 #bjf ,phyllachne clavigera1 #dj ,phyllites nervulosis1 #chc ,phyllocladus1 #edb1 #edc ,phylloglossum1 #cj1 #ca1 #cc ,p4 ,drummondi1 #cc ,phytolithus cancellatus1 #abf ,p4 parmatus1 #abi ,p4 verrucosus1 #bca ,picea excelsa1 #id ,pilularia1 #fg1 #dgc ,p4 globulifera1 #dgc ,p4 minuta1 #dgc ,p4 pedunculata1 #dge ,pinakodendron1 #bfd ,p4 musivum1 #bfh ,pinus1 #aid ,p4 attenuata1 #acd ,p4 clausa1 #acd ,p4 excelsa1 #agd1 #ahb ,p4 longifolia1 #ie1 #ih ,plagiogyria1 #big ,plant1 ,n41 #agg ,platyzoma1 #bia ,p4 microphylla1 #cab ,pleuromeia1 #ff-gc1 #ia1 #ada ,p4 oculina1 #fi ,p4 ,sternbergii1 #fh-gj ,podocarpus1 #baj ,p4 dacrydioides1 #ge ,podoloma polypodioides1 #cid ,poecilitostachys1 #ia ,p4 ,hangi1 #ia ,polypodiaceae1 #bif1 #cge-chj ,polypodium1 #cdd ,p4 ,billardieri1 #cjb ,p4 carnosum1 #cja ,p4 heracleifolius1 #chc ,p4 oregonense1 #cgg ,p4 quercifolium1 #big1 #bih1 #cjb1 #cjc1 #cib1 #ebh ,p4 vulgare1 #cja1 #cac1 #egg ,potoni1 ,h4 ,see p4 #fji ,prantl1 ,k41 #bif ,presl1 ,c4 ,b41 #abg1 #cef1 #cij1 #djg1 #dgg1 #ebe1 #egb ,prestwick4 ,j41 #bbi ,primofilices1 #dcc ,protophyllocladus1 #edc ,protopteris1 #cgj-cgd1 #cij ,p4 punctata1 #cgc-cge ,p4 ,sternbergii1 #cga ,p4 ,witteana1 #cgd1 #cge ,protorhipis asarifolius1 #cij ,protosalvinia1 #dgf ,psaronieae1 #dab-dbf ,psaronius1 #cji1 #cgb1 #cif1 #dab-dbf1 #deb ,p4 asterolithus1 #daf ,p4 brasiliensis1 #dbj ,p4 coalescens1 #daf1 #dbj ,p4 ,cottai1 #dae ,p4 ,cromptonensis1 #dac1 #dbe ,p4 infarctus1 #dae-dba1 #dbd ,p4 musaeformis1 #daf1 #dbj ,p4 ,renaulti1 #dac1 #dah1 #dbj1 #dbe ,p4 ,sterzeli1 #dai1 #dbj ,pseudobornia1 #aa ,p4 ursina1 #h ,psilophyton1 #bf-bi ,p4 ,dechianum1 #bg ,p4 filiformis1 #bd ,p4 princeps1 #bf-bi ,p4 robustius1 #bg1 #bi ,psilotaceae1 #ab-ae ,psilotales1 #ag-bi ,psilotiphyllum1 #bf ,psilotites1 #bd1 #be ,p4 filiformis1 #bd ,p4 lithranthracis1 #be ,p4 unilateralis1 #be ,psilotum1 #ab-bd1 #bf1 #bi1 #bcg ,p4 complanatum1 #ah ,p4 triquetrum1 #ag1 #ah1 #bj ,psygmophyllum1 #dca ,pteridospermaphyta1 #bgh ,pteridosperms1 #bhb1 #cie1 #cif1 #djc1 #djg1 #dbf1 #dhd-ehj ,pteridotheca1 #cbe1 #cge ,p4 ,butterworthi1 #cbe ,pteris1 #cab1 #ehj ,p4 aquilina1 #cje-cji ,p4 arguta1 #cdd ,pteropsida1 #cab ,ptilozamites1 #eci1 #edf1 #edg1 #eej ,p4 ,heeri1 #edf-edh ,ptychocarpus1 #cig1 #daa1 #egf1 #egh ,p4 oblongus1 #cig ,p4 unita1 #cig1 #djj1 #egh ,ptychopteris1 #dac1 #dad1 #dbb-dbd ,rachiopteris antiqua1 #ddi ,r4 corrugata1 #dej1 #dee1 #dfj ,r4 cylindrica1 #dch ,r4 duplex1 #ddg1 #ddh ,r4 hirsuta1 #dcf1 #dch1 #ddb ,r4 inaequalis1 #dec1 #ded ,r4 insignis1 #def ,r4 irregularis1 #dec1 #ded ,r4 ramosa1 #dcf1 #ddj ,r4 tridentata1 #dch ,raciborski1 ,m41 #cci1 #cda1 #cdh1 #cec1 #edc ,regnellidium1 #dgc1 #dgi ,r4 diphyllum1 #dgd1 #dgi ,reinecke1 ,f41 #cja ,reinsch1 ,p4 ,f41 #aib ,renault1 ,b4 ,see note1 p4 #fji ,renault1 ,b4 and ,c4 ,grand',eury1 #bai ,renault1 ,b4 and ,a4 ,roche1 #bjd ,renault1 ,b4 and ,r4 ,zeiller1 #eaj1 #eee1 #efj1 #ega1 #egg ,renaultia1 #cid1 #djf ,renier1 ,a41 #acc ,rhacophyllum1 #ebe ,r4 crispum1 #ebf ,rhaciopterideae1 #ddi ,rhacophyton condrusorum1 #ecg ,rhacopteris1 #dbf1 #dcj1 #dca1 #ebe1 #efc1 #efd ,r4 flabellata1 #dbh ,r4 paniculifera1 #dbh ,rhizodendron oppoliense1 #cge ,rhizomopteris1 #cha ,r4 cruciata1 #chh ,r4 major1 #chc ,r4 ,schenki1 #chb ,rhodea1 #bg1 #abi1 #aif1 #bea ,r4 moravica1 #cfd ,r4 patentissima1 #cfd ,rhytidodendron1 #bea ,r4 minutifolium1 #bea ,rhytidolepis1 #aih1 #bjc1 #bbb1 #bcg ,richter1 ,p4 ,b41 #cij1 #cib1 #cic ,rodway1 ,j41 #ic ,roehl1 von1 #ega ,roemer1 ,f41 #ega ,rotularia cuneifolia1 #a ,royle1 ,j4 ,f41 #eja ,rudolph1 ,k41 #dad1 #dag1 #dah ,ruffordia1 #cej ,r4 ,goepperti1 #cdi1 #cej ,saccoloma1 #dbj ,s4 adiantoides1 #dbd ,sadleria1 #cdd ,salfeld1 ,h41 #ede1 #edf ,sagenaria ,bischofi1 #fi ,s4 ,veltheimiana1 #aga ,sagenopteris1 #dca1 #dgg-dhc ,s4 angustifolia1 #dgh1 #dhb ,s4 bilobata1 #dha ,s4 cuneata1 #dha ,s4 grandifolia1 #dhb ,s4 longifolia1 #dhb ,s4 ,mantelli1 #dca1 #dhb ,s4 ,nathorsti1 #dhb ,s4 ,nilssoniana1 #dgh ,s4 ,phillipsi1 #dca1 #dgh-dhb ,s4 ,phillipsi1 f4 pusilla1 #dhb ,s4 rhoifolia1 #dgi-dhb ,salvinia1 #dge ,s4 ,alleni1 #be ,s4 auriculata1 #dgf ,s4 elliptica1 #dge ,s4 formosa1 #dgf ,s4 natans1 #dge ,s4 reticulata1 #be ,s4 ,zeilleri1 #dgf ,salviniaceae1 #dge-dgg ,samaropsis1 #eag ,saporta1 le ,marquis de1 #ff-fh1 #cea1 #cfj1 #chj1 #ede1 #edf1 #edh1 #eeb ,schenk1 ,a41 #cda1 #ceb1 #cef1 #ceh1 #cfa1 #cfc1 #dgd1 #dhb1 #dib1 #edd1 #ede1 #edi ,scheuchzer1 ,j4 ,t41 #egj1 #egd ,schimper1 ,w4 ,p41 #be1 #aij1 #beg1 #cfd1 #cgf1 #dgg1 #dhf1 #dif1 #ebc1 #edd1 #edf1 #efj1 #egi ,schimper1 ,w4 ,p4 and ,a4 ,mougeot1 #ij1 #eai ,schizaea1 #cab ,s4 dichotoma1 #cjg ,s4 elegans1 #bhg1 #cjg ,s4 pusilla1 #bhg ,schizaeaceae1 #bhf1 #bhg1 #cdf-cea ,schizoneura1 #ebc ,schizopteris1 #ebe ,s4 adnascens1 #djd ,s4 pinnata1 #dde1 #dfd ,s4 lactuca1 #ebf ,schizostachys frondosus1 #dfd ,schlotheim1 ,e4 ,f4 von1 #dac1 #efj1 #egd1 #egg ,schmalhausen1 ,j41 #beg1 #efc ,schuster1 ,j41 #eei ,schwarz1 ,e4 ,h4 ,l41 #bei ,scleropteris1 #eeb1 #egh ,s4 ,pomelii1 #eeb ,scolecopteris1 #dja1 #djb1 #dbf ,s4 elegans1 #djj1 #dja ,s4 polymorpha1 #dja ,scolopendrium nigripes1 #cjj1 #eac ,s4 vulgare1 #eac ,scott1 ,d4 ,h4 ,see note1 p4 #fji ,scott1 ,mrs ,d4 ,h41 #aib1 #dfi ,selaginella1 #ag1 #cj-cc1 #ci1 #di-eh1 #gd-gg1 #he1 #hg1 #hh1 #ahd1 #bae1 #bag1 #bfc1 #bgd-bgh ,s4 apus1 #eg ,s4 arabica1 #hj ,s4 ,berthoudi1 #hd ,s4 caulescens1 #he ,s4 erythropus1 #ec ,s4 grandis1 #ej-ec1 #ge1 #hd ,s4 inaequalifolia1 #ed ,s4 laevigata1 #ed ,s4 lepidophylla1 #cc ,s4 ,martensii1 #ea1 #ec ,s4 revoluta1 #hj ,s4 rupestris1 #eb1 #ef1 #eg ,s4 spinosa1 #ca1 #cc1 #ej1 #eb1 #ec1 #ee1 #bgh1 #ddj ,s4 spinulosa1 #bc ,s4 ,willdenowii1 #eb1 #ec ,selaginellaceae1 #cb1 #cc ,selaginellites1 #gd-gg1 #he-hh ,s4 elongatus1 #hj1 #hg1 #hh ,s4 primaevus1 #hj1 #hf-hh ,s4 suissei1 #gi1 #he-hh ,sellards1 ,e4 ,h41 #dhf1 #dhh1 #ech ,senftenbergia1 #cdg1 #djd ,s4 elegans1 #cdf1 #cfd ,s4 plumosa1 #djd ,shattock1 ,s4 ,g41 #aca ,sigillaria1 #ci1 #dc1 #dd1 #ee1 #fa1 #ff1 #fi-ge1 #ib1 #ih1 #ii1 #aje1 #aji1 #aaj1 #abh1 #adj1 #agj1 #aif-bbf1 #bcj1 #bca1 #bcd1 #bch-bdj1 #bdh1 #bff-bfi1 #dba ,s4 ,brardi1 #agi1 #ahj1 #aih1 #bjj-bjc1 #bjg1 #baj1 #bab1 #bac1 #bai1 #bbd-bbf1 #bda1 #bfa1 #bfe-bfg ,s4 denudata1 #bjc ,s4 discophora1 #aci1 #bji1 #bdi ,s4 elegans1 #afj1 #aig1 #bag-bbd ,s4 elongata1 #bba1 #bbb1 #bbd ,s4 ,eugenii1 #aih ,s4 laevigata1 #aih1 #bjj1 #bjb ,s4 lepidodendrifolia1 #bjj ,s4 ,mc,murtriei1 #aii ,s4 mammillaris1 #aih1 #aii ,s4 ,menardi1 #bbd ,s4 minutifolia1 #bea ,s4 mutans1 #bbd ,s4 oculina1 #fi-gc ,s4 pachyderma1 #aih ,s4 rimosa1 #bdh ,s4 rhomboidea1 #bjc ,s4 rugosa1 #aig1 #aih1 #bjj ,s4 scutellata1 #aif1 #aih1 #bab1 #bba1 #bbb ,s4 spinulosa1 #bja1 #bab1 #bai1 #bbd ,s4 ,sternbergii1 #fi ,s4 ,taylori1 #bji ,s4 tessellata1 #aig ,s4 vascularis1 #aaj ,s4 ,vanuxemi1 #gh ,s4 xylina1 #bba ,sigillariophyllum1 #bjj ,sigillariopsis1 #bac1 #bad ,s4 ,decaisnei1 #bac ,s4 sulcata1 #bad ,sigillariostrobus1 #bjj1 #bae-bag ,s4 bifidus1 #bf ,s4 ciliatus1 #baf ,s4 major1 #bag1 #bbf ,s4 nobilis1 #bae ,s4 rhombibracteatus1 #baf ,s4 ,teighemi1 #bae1 #baf ,simplices1 #bhd1 #bih ,smith1 ,g4 ,o4 and ,d4 ,white1 #bh1 #efc ,solenites ,murrayana1 #fg ,sollas1 ,igerna ,b4 ,j41 #hb1 #hc ,solms-,laubach1 ,h4 ,graf zu4 ,see note1 p4 #fji ,speirocarpus1 #dji ,s4 tenuifolius1 #ccb ,s4 virginiensis1 #ccb ,spencerites1 #dg1 #di1 #aib-aie1 #bfc ,s4 insignis1 #aib-aie ,s4 membranaceus1 #aie ,sphenolepidium1 #ci ,sphenophyllales1 #a-af ,sphenophyllostachys1 #g1 #i ,s4 ,dawsoni1 #a1 #b1 #f1 #ad ,s4 fertilis1 #d1 #e1 #ab ,s4 ,roemeri1 #a-c1 #ad ,sphenophyllum1 #a-g1 #aj-ag1 #ba1 #dcj ,s4 cuneifolium1 #b ,s4 fertile1 #d ,s4 majus1 #b1 #c1 #ad ,s4 myriophyllum1 #b ,s4 plurifoliatum1 #b1 #d ,s4 trichomatosum1 #c1 #d ,sphenopteris1 #ebi-egh ,s4 affinis1 #ecj-ecb ,s4 arguta1 #cfg1 #cfh ,s4 caudata1 #djd ,s4 condrusorum1 #ecg ,s4 coralloides1 #dgj ,s4 cristata1 #djb1 #cff ,s4 dissecta1 #ecb ,s4 elegans1 #ecb ,s4 furcata1 #ebi1 #ecj1 #ece ,s4 ,hoeninghausi1 #ecb ,s4 hymenophylloides1 #cfg1 #cfh ,s4 ,linkii1 #ecb ,s4 ,mantelli1 #cgh ,s4 ,matheti1 #ebf ,s4 nephrocarpa1 #cfg ,s4 obtusiloba1 #ebi1 #ecj ,s4 petiolata1 #ddf ,s4 quinqueloba1 #cgj ,s4 ,rallii1 #cbe1 #djb ,s4 stipata1 #cfg ,spieker1 ,t41 #fi ,spiropteris1 #egi ,spirorbis1 #ajb-ajd ,sprengel1 ,a41 #dab ,stangeria paradoxa1 #cjg ,staphylopteris ,peachii1 #eca ,stauropteris1 #dcc1 #dcd1 #dfe-dfi ,s4 burntislandica1 #dfh1 #dfi ,s4 oldhamia1 #ddd1 #dej1 #dfe-dfh ,steffensia silesiaca1 #djd ,steinhauer1 ,h41 #abf-abh1 #bbh1 #bbi ,stenzel1 ,c4 ,g41 #cge1 #dag1 #dah1 #dce1 #dej-dec ,sternberg1 ,c4 von1 #aje1 #aaj1 #abd1 #abf1 #aih1 #dac1 #egc ,sterzel1 ,j4 ,t41 #cff1 #djb1 #dab1 #dac ,stiehler1 ,a4 ,w41 #did ,stigmaria1 #ff1 #ada1 #aec1 #aeh1 #bbf-bdg1 #bef1 #bfa1 #bfe ,s4 anabathra1 #bca ,s4 ficoides1 #aeh1 #aei1 #agd1 #bbf-bcb1 #bcf-bci1 #bdf1 #bdg1 #bef1 #bfa ,s4 ficoides minuta1 #bee ,s4 flexuosa1 #bci ,s4 inaequalis1 #agd ,s4 radiculosa1 #aeg-afj ,s4 rimosa1 #bbf ,s4 stellata1 #bdg ,stigmariopsis1 #bje1 #bjh1 #bcc-bci ,s4 anglica1 #bce ,stokes and ,webb1 #did ,stopes1 ,marie ,c41 #dcf ,strasburger1 ,e41 #cih ,stromatopteris1 #bia ,stur1 ,d4 ,see note1 p4 #fji ,sturiella1 #cbd ,sub-,sigillariae1 #bjc ,sudworth1 ,g4 ,b41 #acd ,sykes1 ,m4 ,gladys1 #bc1 #dg ,syringodendron1 #aih1 #bjd1 #bje1 #bba1 #bbf1 #bcc1 #bch ,s4 esnostense1 #bjd ,s4 striatum1 #aih ,szajnocha1 ,l41 #edj ,taeniopteris1 #dhe-did1 #ejh1 #eji ,t4 ,beyrichii1 #did ,t4 ,carnoti1 #dhe1 #dhh1 #dij ,t4 ,carruthersi1 #dia ,t4 coriacea1 #dhh1 #dij ,t4 ,daintreei1 #dij1 #dia ,t4 gigantea1 #dhi ,t4 immersa1 #dib ,t4 jejunata1 #dhe1 #dhh ,t4 ,jourdyi1 #dhi ,t4 lata1 #dhi ,t4 ,lescuriana1 #dhg ,t4 major1 #did ,t4 marantacea1 #djg1 #djh ,t4 mareyiaca1 #dia ,t4 missouriensis1 #dhe ,t4 multinervis1 #dhf-dhh ,t4 ,newberriana1 #dhh ,t4 spatulata1 #dhi1 #dij ,t4 superba1 #dhi ,t4 tenuinervis1 #dhi1 #dib ,t4 virgulata1 #dib ,t4 vittata1 #dhe1 #dhi1 #dib-did ,tafalla graveolens1 #dj1 #ge ,tansley1 ,a4 ,g41 #af1 #bhj1 #caj1 #ddj1 #ddf ,telangium1 #ecb ,t4 ,scotti1 #ecb ,teratophyllum aculeatum1 #cja1 #dje ,thamnocladus1 #bg ,thamnopteris1 #cbf1 #cbi-cca1 #ccd1 #ccg1 #cch ,t4 ,schlechtendalii1 #cbi1 #ccj1 #ddh1 #dec ,thaumatopteris1 #che ,t4 ,brauniana1 #che ,t4 ,muensteri1 #chf ,t4 ,schenki1 #che ,theobroma1 #bji ,thinnfeldia1 #ecg-eeb1 #eef ,t4 falcata1 #edj ,t4 ,fontainei1 #edc ,t4 lancifolia1 #eci ,t4 odontopteroides1 #ech1 #eda-edc1 #edf ,t4 rhomboidalis1 #edb-ede ,t4 tenuinervis1 #edj ,t4 variabilis1 #dhb1 #edc ,thoday1 ,d41 #f ,thomas1 ,a4 ,p4 ,w41 #ab1 #ac1 #ag1 #ai1 #bc ,thomas1 ,ethel ,n41 #bci ,thompson1 ,d',arcy ,w41 #aca1 #bji ,thyrsopteris1 #bie1 #bif1 #cfi ,t4 elegans1 #bhi1 #bid1 #cjh1 #cfh ,t4 elongata1 #cgh ,t4 ,murrayana1 #cfg ,t4 rarinervis1 #cfi ,t4 schistorum1 #cff ,tmesipteris1 #d1 #ab-be ,t4 tannensis1 #ag ,todea1 #bfg1 #ccg1 #cda1 #dfh ,t4 australis1 #cdf ,t4 barbara1 #bhe1 #bhf1 #bii1 #cad1 #ccc1 #cci ,t4 hymenophylloides1 #cbe ,t4 ,lipoldi1 #cbi ,t4 superba1 #ccc ,t4 ,wilkesiana1 #bhf ,todeopsis primaeva1 #cbd1 #cdj ,todites1 #cci-cdc1 #eej ,t4 ,roesserti1 #cdf ,t4 ,williamsoni1 #ccb1 #cci-cdc1 #ceb ,tracheotheca1 #dcg1 #ddc ,trautschold1 ,h4 and ,j4 ,auerbach1 #bfj ,treub1 ,m41 #cjg1 #cjh ,trichomanes1 #bic1 #bid1 #cjc1 #cfe1 #deb ,t4 ,goebelianum1 #cjj ,t4 radicans1 #bid1 #cae1 #dgj ,t4 reniforme1 #cjj1 #caj1 #caa1 #cae1 #ddj1 #ega ,t4 scandens1 #caa ,trigonocarpon1 #egd ,triletes1 #aib1 #bae ,triplosporites1 #aij ,tubicaulis1 #dcd-dcf1 #ddc1 #dga ,t4 primarius1 #ddc ,t4 solenites1 #dce ,t4 ,sutcliffi1 #dcf ,tylophora radiculosa1 #aeg ,tympanophora racemosa1 #cfg ,t4 simplex1 #cfg ,ulodendron1 #ie1 #abh-ace1 #acg1 #ach1 #ahe1 #bji1 #baj1 #bea1 #bed1 #bee ,u4 minus1 #bji ,unger1 ,f41 #ahj1 #dab1 #ddf1 #ddi ,urnatopteris1 #cif1 #djg ,urophlyctites stigmariae1 #bdg ,variolaria ficoides1 #bca ,velenovsk1 ,j41 #cfi1 #cgb1 #dhb1 #edc ,veronica1 #ge ,vertebraria1 #dig1 #eja-eje ,v4 indica1 #ejb1 #ejc ,vittaria1 #cjf ,volkmann1 ,g4 ,a41 #abd1 #bca ,walchia1 #be ,wanklyn1 ,a41 #cee ,ward1 ,l4 ,f41 #bgh1 #cfi ,watson1 ,d4 ,m4 ,s41 #aca1 #aef1 #afa1 #aie1 #bfa1 #bfc1 #bgh1 #cig ,weber1 ,o4 and ,j4 ,t4 ,sterzel1 #eeh ,weichselia1 #did-dif1 #egf ,w4 erratica1 #die ,w4 ,mantelli1 #did-dif ,w4 reticulata1 #did ,weiss1 ,c4 ,e41 #gc1 #ajg1 #bjc1 #bec1 #beg1 #bfd1 #cbd1 #dbi1 #dcj1 #dhf1 #eee-efj ,weiss1 ,f4 ,e41 #ih1 #aja1 #ajb1 #ach1 #aci1 #aea1 #aed1 #aeg1 #ahb1 #bdj-bdb1 #bde-bdg1 #bfa1 #dfa ,welwitschia1 #bgh ,white1 ,d41 #bg1 #bi1 #bja1 #bfd1 #bfe1 #cdf1 #cgg1 #dfd1 #dhe1 #dih1 #eac1 #eaf1 #efj ,wickes1 ,w4 ,h41 #hb ,widdringtonites1 #ci ,wild1 ,g4 and ,j4 ,lomax1 #bga ,williamson1 ,w4 ,c4 ,see note1 p4 #fji ,williamson1 ,w4 ,c4 and ,d4 ,h4 ,scott1 #f ,witham1 ,h41 #afj ,woodwardia1 #cei ,woodwardites1 #cgg ,wnsch1 ,e4 ,a41 #afc ,xenophyton radiculosum1 #aeh ,xenopteris1 #eee ,yabe1 ,h41 #cgg1 #dha ,yokoyama1 ,m41 #cdi1 #cgg ,young1 ,g4 and ,j4 ,bird1 #hc ,zalessky1 ,m41 #ega ,zalesskya1 #cbf-ccj1 #ccb1 #ccg1 #cch1 #dfa ,z4 diploxylon1 #cbf-cca ,z4 gracilis1 #cbf-cca ,zeiller1 ,r4 ,see note1 p4 #fji ,zeilleria1 #djg ,z4 avoldensis1 #djg ,z4 delicatula1 #djg ,zenker1 ,j4 ,c41 #dja ,zigno1 ,a4 de1 #cec1 #cij1 #daj1 #dgh1 #dhb1 #edf-eej ,zygoptereae1 #ddc-dfe ,zygopteris1 #dah1 #ddi ,z4 bibractensis1 #dec1 #dee ,z4 ,brongniarti1 #dej ,z4 ,lacattii1 #dfc ,z4 pettycurensis1 #ddg ,z4 primaria1 #ddc1 #ddd1 #ddf1 #dea ,z4 ,roemeri1 #ddg1 #ddh ,z4 scandens1 #dej ---------------------------------------- ------------------------------ ,,footnotes3 #a ,the full titles of books and papers referred to in footnotes distinguished by the addition of ,a after the date are given in the ,bibliography at the end of ,volume ,i4 #b ,chap4 ,,xi4 #c ibid4 p4 #dje4 #d ,sternberg 7#bc7 ,a4 p4 #cc1 ,pl4 ,,xxvi4 figs4 #d a1 #d b4 #e ,scott 7#je7 p4 #cd4 #f ,zeiller 7#hh7 ,a4 ,pl4 ,,lxii4 figs4 #b--d4 #g ,vol4 ,i41 p4 #cig4 #h ,kidston 7#ja7 p4 #abh1 fig4 #be2 7#jb7 p4 #cfa1 fig4 #ac4 #i ,bower 7#jh7 p4 #djd1 fig4 #bba4 #aj ,kidston 7#ia7 p4 #ei1 ,pl4 ,i42 7#ja7 p4 #abc1 fig4 #bb4 #aa ,scott 7#je74 #ab ,see also ,browne1 ,lady ,isabel 7#ji7 p4 #d4 #ac ,williamson and ,scott 7#id7 ,a4 p4 #iaa4 #ad ,thoday 7#jf74 #ae ,scott 7#ig7 ,a42 see also ,scott 7#jj7 p4 #ajf4 #af ,the term metaxylem may be conveniently applied to the primary xylem other than protoxylem2 the latter is usually but by no means invariably characterised by spiral thickening bands4 #ag ,scott 7#je7 p4 #ba 7footnote74 #ah ,vol4 ,i4 p4 #ced1 fig4 #ie1 ,c4 #ai ,williamson 7#gb7 ,pl4 ,,xliv4 p4 #big1 figs4 #bi1 #cj4 #bj #8,exarch' denotes that the protoxylem is on the outside of the primary xylem2 #8endarch' that it is on the inner edge or in a central position2 #8mesarch' that it is internal1 either near the inner or the outer edge of the metaxylem4 #ba ,nathorst 7#jb7 p4 #bd4 #bb ,heer 7#ga7 p4 #cb1 ,pls4 ,i--,,vi4 #bc ,scott 7#jg7 p4 #aee4 #bd ,thomas1 ,a4 ,p4 ,w4 7#jb7 p4 #cej4 #be ,bower 7#jd7 p4 #bbg2 7#jh7 p4 #dbd4 #bf ,see p4 #ai4 #bg ,scott 7#jj7 p4 #dii4 #bh ,bower 7#id7 p4 #ede4 #bi ,thomas 7#jb74 ,see also ,sykes 7#jh74 #cj ,sykes 7#jh74 #ca ,boodle 7#jd72 see postea p4 #ba4 #cb ,bower 7#jh7 p4 #dbf4 #cc ,lignier 7#jc72 7#jh74 #cd ,tansley 7#jh7 p4 #bf1 who refers to similar views held by ,potoni and by ,hallier4 #ce ,on the morphology of ,sporangiophores1 see also ,benson 7#jh7 and ,scott1 ,d4 ,h4 7#ji7 p4 #fbc4 #cf ,scott 7#jj74 #cg ,thomas 7#jb74 #ch ,bower 7#jh7 p4 #cih4 #ci ,dangeard 7#ia7 and ,bertrand1 ,c4 ,e4 7#ha7 recognise other species of ,tmesipteris1 but it is doubtful how far such differences as exist are worthy of specific recognition4 #dj ,baker 7#hg7 ,a4 p4 #cj4 #da ,thomas 7#jb7 p4 #cdi4 #db ,another form of abnormality in the sporophylls of ,psilotum has recently been described by ,miss ,sykes4 ,sykes 7#jh74 #dc ,bertrand1 ,c4 ,e4 7#ha72 ,ford 7#jd74 #dd ,boodle 7#jd74 #de ,see p4 #aej4 #df ,bertrand 7#ha72 ,jennings and ,hall 7#ia74 #dg ,sykes 7#jh74 #dh ibid4 7#jh74 #di ,lignier 7#jh74 #ej ,bower 7#id72 7#jh74 #ea ,bertrand 7#ha7 p4 #bed4 #eb ,mnster 7#db7 p4 #ajh1 ,pl4 ,,xiii4 fig4 #aa2 ,pl4 ,,xv4 fig4 #bj4 #ec ,schimper 7#gj7 ,a4 p4 #ge4 #ed ,goldenberg 7#ee7 p4 #ac1 ,pl4 ,,ii4 fig #g4 #ee ,kidston 7#hf74 #ef ,hollick 7#id7 p4 #bee1 figs4 #ab1 #ac4 #eg ,lesquereux 7#gh7 ,pl4 ,v4 fig4 #aa4 #eh ,since this was written ,i have had an opportunity of seeing a leaf labelled ,tmesipteris from the ,tertiary plant-beds of ,florissant in a collection recently acquired by the ,british ,museum3 the specimen bears no resemblance to a leaf of the recent genus4 #ei ,marion 7#ij74 #fj ,potoni 7#ic7 ,a4 p4 #aig1 ,pls4 ,,xxvii41 ,,xxviii41 ,,xxxiii4 #fa ,potoni 7#ia72 7#ic7 ,a4 p4 #aig4 #fb ,geinitz 7#gc7 p4 #gjj1 ,pl4 ,,iii4 figs4 #e-g4 #fc ,seward and ,gowan 7#jj7 p4 #acg2 ,seward and ,ford 7#jf7 p4 #cgd4 #fd ,dawson 7#ei7 ,a4 p4 #dgh1 fig4 #a4 #fe ibid4 7#ga7 ,a4 p4 #ch4 #ff ,solms-,laubach 7#ie7 ,a4 #fg ,dawson 7#ga7 ,a4 ,cf4 ,pl4 ,,xi4 figs4 #aca1 #acd1 etc4 #fh ,carruthers 7#gc74 #fi ,goeppert 7#eb7 ,a4 #gj ,carruthers 7#gc74 #ga ,white 7#jb74 #gb ,crpin 7#ge74 #gc ,stur 7#ge7 ,a4 p4 #cc4 #gd ,carruthers 7#gc74 #ge ,gilkinet 7#ge7 figs4 #b-e4 #gf ,penhallow 7#ib7 p4 #h4 #gg ,smith and ,white 7#je7 p4 #eh1 ,pls4 ,v4 ,,vi4 #gh ,kidston 7#hf7 p4 #bcb4 #gi ,stur 7#ha7 ,pls4 ,,iii4 ,,iv4 #hj ,jahn 7#jc7 p4 #gg4 #ha ,smith and ,white 7#je7 p4 #fc4 #hb ,nathorst 7#jb7 p4 #ae1 ,pl4 ,i4 figs4 #ah-ce4 #hc ,for a general account of recent ,lycopodiales see ,pritzel 7#jb72 ,campbell 7#je72 ,bower 7#jh74 #hd ,bruchmann 7#ig74 #he ,treub 7#hd-ij72 see also ,lang 7#ii7 and ,bruchmann 7#ih74 #hf ,see ,baker 7#hg7 ,a4 #hg ,the ,rose of ,jericho is ,anastatica ,hierochuntina ,l4 a ,cruciferous plant4 #hh ,baker 7#hg7 ,a4 p4 #cd4 #hi ,vines 7#hh74 #ij ,scott and ,hill 7#jj74 #ia ,for ,phylloglossum1 see ,bertrand 7#hb72 ,bower 7#id71 7#jh72 ,campbell 7#je74 #ib ,treub 7#hd-ij72 ,bruchmann 7#ih72 ,lang 7#ii74 #ic ,sykes 7#jh74 #id ,bommer 7#jc7 ,pl4 ,,ix4 figs4 #adj1 #ada4 #ie ,hooker 7#dh7 p4 #dbc1 figs4 #ab-ad4 #if ,jones 7#je74 #ig ,boodle 7#ja7 ,pl4 ,,xix4 #ih ,this species is figured under the name ,lycopodium crassum by ,hooker and ,greville 7#ca7 ,pl4 #bbd4 ,see also ,brongniart 7#cg7 ,pl4 ,i4 fig4 #a4 #ii ,hegelmaier 7#gb74 ,see also ,hill1 ,t4,g4 7#jf7 p4 #bfi2 this author draws attention to the fact that in some species of ,lycopodium the mucilage canals are confined to the sporophylls4 #ajj ,professor ,yapp has drawn my attention to the very close anatomical resemblance between a specimen of ,lycopodium salakense obtained by him from ,gunong ,inas in the ,malay ,peninsula and ,l4 cernuum as represented in fig4 #abe1 ,h and ,i4 #aja ,jones 7#je74 #ajb ,strasburger 7#gc7 p4 #aji2 ,brongniart 7#cg7 ,pl4 #h2 7#ci7 ,a4 ,pl4 #cb3 ,brongniart figures stems of ,l4 ,phlegmaria and other species showing roots in the cortex4 ,see also ,goldenberg 7#ee72 ,bruchmann 7#gd72 ,saxelby 7#jh74 #ajc ,since this was written a comparative account of the sporophylls of ,lycopodium has been published by ,miss ,sykes4 ,sykes 7#jh74 #ajd ,bower 7#id7 p4 #ead2 7#jh74 #aje ,seward and ,ford 7#jf74 #ajf ,goebel 7#je7 p4 #egi4 #ajg ,bower 7#id74 #ajh ibid4 7#id7 ,pl4 ,,xlviii4 #aji ,kidston 7#hc7 ,pl4 ,,xxxi4 figs4 #b-d4 #aaj ,lang 7#jh74 #aaa ,see page #aib1 and ,watson 7#ji74 #aab ,lang 7#jh7 p4 #ceg4 #aac ,bruchmann 7#ig74 #aad ,gard4 ,chron4 7#hb74 #aae ,harvey-,gibson 7#jb74 #aaf ibid4 7#id7 7#ig7 7#jb74 #aag ,bower 7#ic74 #aah ,harvey-,gibson 7#id7 p4 #aeb4 #aai ibid4 7#id7 p4 #aid2 ,scott 7#if7 p4 #i4 #abj ,bruchmann 7#ig74 #aba ,the term solenostele1 first used by ,van ,tieghem and revived by ,gwynne-,vaughan1 may be applied to a stem in which the vascular tissue has the form of a hollow cylinder with phloem and endodermis on each side of the xylem4 ,as each leaf-trace is given off the continuity of the vascular tube is interrupted4 ,see ,gwynne-,vaughan 7#ja7 p4 #gc4 #abb ,harvey-,gibson 7#id7 ,pl4 ,,xii1 fig4 #ic4 #abc ,harvey-,gibson 7#jb74 #abd ibid4 7#ig74 #abe ibid4 7#if74 #abf ,bower 7#jh7 p4 #cae4 #abg ,hieronymus 7#jb74 #abh ,goebel 7#je7 p4 #eha4 #abi ,lyon 7#ja7 p4 #ace4 #acj ,see p4 #bga4 #aca ,campbell 7#je7 p4 #ebb4 #acb ,motelay and ,vendrys 7#hb74 #acc ,campbell 7#je7 p4 #efa4 #acd ,scott and ,hill 7#jj74 #ace ,motelay and ,vendrys 7#hb7 ,pls4 ,,xvi1 ,,xvii4 #acf ,braun 7#fc74 #acg ,hill1 ,t4 ,g4 7#jd7 7#jf74 #ach ,for figures1 see ,motelay and ,vendrys 7#hb72 ,bennie and ,kidston 7#hh7 ,pl4 ,,vi4 #aci ,solms-,laubach 7#jb74 #adj ,see ,von ,mohl 7#dj72 ,farmer 7#ij74 #ada ,von ,mohl 7#dj74 #adb ,hofmeister 7#fb74 #adc ,farmer 7#ij72 ,scott and ,hill 7#jj74 #add ,miss ,stokey 7#ji71 in a paper which appeared since this account was written1 criticises the conclusions of ,scott and ,hill 7#jj74 #ade ,von ,mohl 7#dj74 #adf ,saporta 7#id7 p4 #acd1 ,pls4 ,,xxiv4 ,,xxv4 ,,xxvii4 #adg ,mnster 7#db7 p4 #ajg1 ,pl4 ,,iv4 fig4 #d4 #adh ,phillips 7#bi7 ,a ,pl ,x4 fig4 #ab4 #adi ,lindley and ,hutton ,a 7#cd7 ,pl4 ,,cxxi4 #aej ,nathorst 7#jf72 ,seward 7#jj7 p4 #bgh4 #aea ,saporta 7#hh7 p4 #bh1 ,pl4 ,,ii4 pp4 #af-bj4 #aeb ,heer 7#gf7 ,a4 #aec ,corda1 in ,germar 7#eb74 #aed ,mnster 7#db7 ,a4 #aee ,solms-,laubach 7#ii74 #aef ,germar 7#eb74 #aeg ,bischof 7#ec74 #aeh ,potoni 7#ja7 p4 #ged2 7#jd7 ,lief ii4 #aei ,goeppert1 in ,rmer 7#ed7 ,pl4 ,,xv4 fig4 #g4 #afj ,spieker 7#ec74 #afa ,potoni 7loc4 cit474 #afb ,barber 7#hi7 ,pls4 ,v4 ,,vi4 #afc ,fitting 7#jg74 #afd ,potoni 7#jd7 ,lief ii4 #afe ,weiss1 ,c4 ,e4 7#hf74 #aff ,fliche 7#jc74 #afg ,vol4 ,i1 p4 #cjj4 #afh ,halle 7#jg7 p4 #a4 #afi ,feistmantel 7#ge7 ,a4 p4 #ahc1 ,pl4 ,,xxx4 pp4 #a and #b4 #agj ,germar 7#di7 ,pl4 ,,xxvi2 ,geinitz 7#ee7 ,a4 ,pl4 ,i4 pp4 #e1 #f4 #aga ,bommer 7#jc7 p4 #bi1 ,pl4 ,,ix1 figs4 #ach-ada4 #agb ,solms-,laubach 7#ia7 ,a4 p4 #acg4 #agc ,zeiller 7#jf7 p4 #adj4 #agd ,halle 7#jg74 #age ,brongniart 7#bb7 ,a4 p4 #cjd1 ,pl4 ,,vi1 fig4 #a4 #agf ,brongniart 7#bh7 ,a4 p4 #hc4 #agg ,brongniart 7#di7 ,a4 p4 #dj4 #agh ,goldenberg 7#ee7 p4 #i4 #agi ,lesquereux 7#hd7 ,a4 p4 #ggg4 #ahj ,kidston 7#hf7 p4 #efa4 #aha ,halle 7#jg74 #ahb ,renault 7#fi7 p4 #agh1 ,pls4 ,,xii-,,xiv4 #ahc ,renault 7#if7 ,a4 p4 #bdi4 #ahd ,kidston 7#hf74 #ahe ,goeppert 7#eb7 ,a4 #ahf ,kidston 7#ja7 p4 #ch4 #ahg ,kidston 7#hd7 ,pl4 ,v2 7#ja7 p4 #cg4 #ahh ,bower 7#jh7 p4 #bih1 fig4 #adg4 #ahi ,solms-,laubach 7#ia7 ,a4 p4 #ahf4 #aij ,penhallow 7#ib7 ,pl4 ,i4 fig4 #b1 p4 #h4 #aia ,goeppert 7#eb7 p4 #ddj4 #aib ,kidston 7#id7 ,a4 p4 #bed4 #aic ,geinitz 7#ee7 ,a4 p4 #cb1 ,pl4 ,i4 fig4 #a4 #aid ,page #hh4 #aie ,kidston 7#ja7 p4 #cf1 fig4 #b1 ,b4 #aif ,kidston 7#ja7 p4 #cg1 fig4 #b1 ,a4 #aig ,goldenberg 7#ee7 ,pl4 ,i4 fig4 #e4 #aih ,halle 7#jg7 ,pl4 ,i4 fig4 #e4 #aii ,page #hi4 #bjj ,halle 7#jg74 #bja ,brodie 7#de7 p4 #ic4 #bjb ,buckman in ,murchison 7#de7 p4 #f4 #bjc ,buckman 7#ej7 p4 #dae1 fig4 #b4 #bjd ,buckman 7#ej7 p4 #dae1 fig4 #d4 #bje ,wickes 7#jj7 p4 #dbb4 #bjf ,sollas 7#ja74 #bjg ,seward 7#jd7 p4 #ad1 ,pl4 ,,ii4 figs4 #b1 #c4 #bjh ,vol4 ,i4 p4 #bdj4 #bji ,sollas 7#ja7 p4 #caa4 #baj ,seward 7#jd7 p4 #ad4 #baa ,halle 7#jg7 p4 #ad1 ,pl4 ,,iii4 figs4 #f-ab4 #bab ,lindley and ,hutton 7#ca7 ,a4 ,pl4 ,,lxi4 #bac ,sternberg 7#ch7 ,a4 p4 #ch4 #bad ,schimper 7#gj7 ,a4 p4 #i4 #bae ,young and ,bird 7#bb7 ,a4 ,pl4 ,,ii4 fig4 #g4 #baf ,no4 #cicad1 ,brit4 ,mus4 #bag ,mller 7#jb7 ,pl4 ,,vi4 fig4 #ba4 #bah ,seward 7#jd7 p4 #afa1 ,pl4 ,,viii4 figs4 #b-d4 ,the drawing is reproduced twice natural size4 #bai ,oldham and ,morris 7#fc7 ,pls4 ,,xxxiii4 ,,xxxv4 #bbj ,feistmantel 7#gg7 p4 #hg4 #bba ,heer 7#gf7 ,pl4 ,,xv4 figs4 #a-h4 #bbb ,nathorst 7#ij7 ,a4 ,pl4 ,,ii4 fig4 #c4 ,saporta 7#id7 ,pls4 ,,xxiii4-,,xxvi4 ,knowlton 7#ih7 p4 #acf4 #bbc ,lesquereux 7#gh7 ,pl4 ,v4 fig4 #ab4 ,see also ,knowlton loc4 cit4 #bbd ,zeiller 7#jf7 p4 #ada1 ,pls4 ,,xxxix4 ,,xli4 #bbe ,zeiller 7#jj7 p4 #ajgg4 #bbf ,bennie and ,kidston 7#hh7 ,pl4 ,,vi4 fig4 #bb4 #bbg ,goldenberg 7#ee7 ,pl4 ,i4 fig4 #c4 #bbh ,schimper 7#gj7 ,a4 ,pl4 ,,lvii4 fig4 #b4 #bbi ,halle 7#jg74 #bcj ,goldenberg 7#ee7 ,pl4 ,i4 fig4 #b4 #bca ,schimper 7#gj7 ,a4 p4 #aj4 #bcb ,nathorst 7#jh74 #bcc ,nathorst 7#jb7 p4 #e1 ,pl4 ,i4 fig4 #a4 #bcd ,fliche 7#jc74 #bce ,fliche 7#ji74 #bcf ,scott 7#ja74 #bcg ,rodway 7#ie7 ,a4 p4 #aec4 #bch ,a good example of an old ,lepidodendron stem 7,l4 aculeatum7 is figured by ,zalessky 7#jd7 ,pl4 ,i4 fig4 #c4 #bci ,seward and ,ford 7#jf7 ,pl4 ,,xxiii4 fig4 ,c4 #bdj ,see ,fischer 7#jd74 #bda ,bertrand1 ,c4 ,e4 7#ia7 p4 #hd3 derived from 1 by the side of1 and 1 trace or foot-print4 #bdb ,renault 7#if7 ,a4 ,pls4 ,,xxxiii4 ,,xxxiv4 p4 #agh4 ,for a good section of another ,lepidodendron leaf1 see ,scott 7#jh7 p4 #afj1 figs4 #fd1 #fe4 #bdc ,weiss1 ,f4 ,e4 7#jg74 #bdd ,for a fuller account of the parichnos1 see ,hill1 ,t4 ,g4 7#jf7 and other papers quoted by ,f4 ,e4 ,weiss 7#jg74 #bde ,barrois 7#jd74 ,see also ,etheridge 7#hj72 ,geikie 7#jc7 p4 #ajdi4 #bdf ,binney 7#dh74 #bdg ,darwin 7#jc7 vol4 ,,ii4 pp4 #bag1 #bbj4 #bdh ,solms-,laubach 7#ib7 ,pl4 ,,ii4 figs4 #b1 #d4 #bdi ,williamson 7#ic7 p4 #aj4 #bej ,potoni 7#je7 ,lief1 iii41 p4 #da4 #bea ,stur 7#ge7 ,a4 ,heft ,,ii4 p4 #bgg4 #beb ,potoni 7#je7 fig4 #d4 #bec ,seward and ,leslie 7#jh7 ,pl4 ,x4 figs4 #a and #b4 #bed ,sternberg 7#bf7 ,a4 ,pl4 ,,xi4 figs4 #b-d2 7#jb7 p4 #bc4 #bee ,corda 7#de7 ,a4 ,pls4 ,i4-,,iv4 #bef ,zeiller 7#ib7 ,a4 #beg ,kidston 7#ic7 p4 #efa1 ,pls4 ,i4 and ,,ii4 #beh ,seward 7#ij74 #bei ,williamson 7#ic7 ,pl4 ,,iv4 figs4 #cj-cb4 #bfj ,binney 7#fb74 #bfa ,binney 7#fe72 see also ,binney 7#gb74 #bfb ,williamson 7#gb74 #bfc ,weiss1 ,f4 ,e4 and ,lomax 7#je74 #bfd ,binney 7#fb74 #bfe ,carruthers 7#fi7 p4 #agi4 #bff ,kidston 7#hf7 ,a4 p4 #aea4 #bfg ,seward 7#jf7 p4 #cgb4 #bfh ,hovelacque 7#ib74 #bfi ,solms-,laubach 7#ib7 ,pl4 ,,ii4 fig4 #f2 ,seward and ,hill 7#jj7 ,pl4 ,,iv4 fig4 #bf4 ,see p4 #iaj of the latter paper for other references4 #bgj ,gwynne-,vaughan 7#jh74 #bga ,jeffrey 7#ih74 ,see also ,tansley 7#jh7 p4 #cg4 #bgb ,seward 7#ii7 p4 #add4 #bgc ,steinberg 7#bf7 ,a4 #bgd ,goeppert 7#eb7 ,a4 p4 #aif4 ,see also ,kidston 7#ja7 p4 #ej4 #bge ibid4 7#eb7 ,a4 p4 #dd4 ,pls4 ,,xxx4 ,,xxxi4 ,lief4 i and ii4 #bgf ,balfour 7#gb7 ,a4 #bgg ,good examples are given by ,schmalhausen 7#gg7 ,pl4 ,,iii4 #bgh ,steinhauer 7#ah7 ,a4 ,pl4 ,,iv4 fig4 #e4 #bgi ,brongniart 7#di7 ,a4 p4 #db4 #bhj ,goldenberg 7#ee74 #bha ,carruthers 7#gc7 p4 #f4 #bhb ,feistmantel 7#ge7 ,a4 #bhc ,potoni 7#je7 ,lief4 ,,iii4 #db-dd4 #bhd ,artis 7#be7 ,a4 ,pls4 ,,xvi4 ,,xxiii4 #bhe ,steinberg 7#ch7 ,a4 #bhf ,stur 7#ge7 ,a4 ,heft ,,ii4 p4 #bbi4 #bhg ,lindley and ,hutton 7#ca7 ,a4 ,pls4 ,v4 and ,,vi4 #bhh ,kidston 7#he74 ,in this important paper ,dr ,kidston gives a full account of the history of our knowledge of ,ulodendron4 #bhi ,steinhauer 7#ah7 ,a4 p4 #bhf1 ,pl4 ,,vii4 fig4 #a4 #bij ,rhode 7#bj7 ,pl4 ,,iii4 #bia ,lindley and ,hutton 7#ca7 ,a4 #bib ,hooker 7#dh71 p4 #dbg4 #bic ,geinitz 7#ee7 ,a4 #bid ,carruthers 7#gj74 #bie ,williamson 7#gb74 #bif ,thompson1 ,d',arcy 7#hj74 #big ,kidston 7#he74 #bih ,seward and ,ford 7#jf7 ,pl4 ,,xxiii4 fig4 ,c4 #bii ,shattock 7#hh74 #cjj ,watson 7#jh74 #cja ,watson 7#jh7 p4 #aj4 #cjb ,renier 7#jh74 #cjc ,stur 7#ge7 ,a4 ,heft ,,ii4 #cjd ,garden and ,forest1 vol4 v41 pp4 #afj-afb1 fig4 #bd 7,april #f1 #aijb74 #cje ,lindley and ,hutton 7#ce7 ,a4 #cjf ,kidston 7#ic7 ,pl4 ,,ii4 fig4 #f4 #cjg ibid4 7#jb7 ,pl4 ,,liii4 fig4 #b4 #cjh ,williamson 7#hc7 ,a4 ,pl4 #cd4 #cji ,feistmantel 7#ge7 ,a4 p4 #aic1 ,pls4 ,,xxxiv4-,,xxxvii4 #caj ,feistmantel loc4 cit4 ,pl4 ,,xlvii4 #caa ,grand',eury 7#ij7 ,a4 #cab ,dawes 7#dh74 #cac ,binney 7#gb72 see also ,seward 7#ii74 #cad ,carruthers 7#gc74 #cae ,williamson 7#gb74 #caf ibid4 7#ic74 #cag ,weiss1 ,f4 ,e4 7#jc74 #cah ,kidston 7#je74 #cai ,renault 7#if7 ,a4 p4 #age1 ,pls4 ,,xxxiii4 ,,xxxiv4 #cbj ,for description of the leaf-anatomy1 see pp4 #ih1 #ii4 #cba ,renault 7#gi7 p4 #bdi1 ,pl4 ,x4 #cbb ,solms-,laubach 7#if7 p4 #ah1 ,pl4 ,x4 figs4 #g-aa4 #cbc ,they are regarded as identical by ,fischer 7#jd74 #cbd ,binney 7#gb7 ,pl4 ,,xiii4 fig4 #a4 #cbe ,seward 7#ii74 #cbf ,as ,miss ,stokey 7#ji7 points out the production of parenchyma internal to the cambium of ,l4 fuliginosum is a feature shared by ,isoetes4 ,see also ,scott and ,hill 7#jj71 p4 #dbd4 #cbg ,williamson 7#ha7 ,a4 ,pl4 ,,lii4 p4 #bhh4 7,will4 ,coll4 ,no4 #cgi47 #cbh ,binney 7#gb74 #cbi ,cash and ,lomax 7#ij74 #ccj ,kidston 7#ic7 p4 #edg4 #cca ,weiss1 ,f4 ,e4 7#jc7 p4 #bah4 #ccb ,scott1 ,d4 ,h4 7#jf74 #ccc ,watson 7#jg7 p4 #ah4 #ccd ,seward 7#jf7 p4 #cgh4 #cce ,weiss1 ,f4 ,e4 7#jb74 #ccf ,hick 7#ic74 #ccg ,hick 7#ic74 #cch ,see p4 #bdj4 #cci ,hick 7#ic7 ,pl4 ,,xvi4 fig4 #a4 #cdj ,witham 7#ca7 ,a4 #cda ,witham 7#cc7 ,a4 ,pls4 ,,xii4 ,,xiii4 #cdb ,lindley and ,hutton 7#ce7 ,a4 ,pls4 #ih1 #ii4 #cdc ,brongniart 7#ci7 ,a4 #cdd ,kidston 7#jc7 p4 #hbb4 #cde ,williamson 7#hg74 #cdf ,kidston 7#jc7 p4 #hbb2 ,watson 7#jg74 #cdg ,bertrand1 ,c4 ,e4 7#ia74 #cdh ,williamson 7#hj7 ,a4 #cdi ,williamson 7#ic7 ,pl4 ,i4 fig4 #c4 #cej ,volume ,i4 p4 #hi4 ,for other references to these stems1 see ,seward and ,hill 7#jj7 p4 #iah4 #cea ,wnsch 7#fg74 #ceb ,carruthers 7#fi7 p4 #f4 #cec ,williamson 7#hj7 ,a42 7#ic72 7#ie74 #ced ,wnsch loc4 cit4 #cee ,binney 7#ga7 p4 #ef4 #cef ,carruthers 7#fi74 #ceg ,seward and ,hill 7#jj74 #ceh ,williamson 7#if7 p4 #age4 #cei ,the term meristematic zone is used because some of the cells in this region are in a state of active division1 though the inner portion may consist of permanent tissue4 #cfj ,scott 7#jj7 p4 #aca2 7#jh7 p4 #adb4 #cfa ,seward and ,hill 7#jj7 ,pl4 ,,ii4 fig4 #ad4 #cfb ,worsdell 7#ie72 ,bernard 7#jd74 #cfc ,no4 #eb1 #fbe4 #cfd ,seward and ,hill 7#jj7 p4 #ibb4 #cfe ,binney 7#ga7 p4 #ef1 ,pl4 ,,xi4 figs4 #b;a-#b;c4 #cff ,williamson 7#gb7 p4 #bih1 pl4 ,,xlv4 fig4 #ce4 #cfg ,carruthers 7#gb74 #cfh ,williamson 7#ic7 p4 #cj4 #cfi ,goldenberg 7#ee7 p4 #ab4 #cgj ,see also ,kidston 7#id71 7#hf7 ,a4 p4 #afj2 ,potoni 7#je7 ,lief4 ,,iii4 #ej4 #cga ,stur 7#ge7 ,a4 ,,ii4 p4 #ccj1 fig4 #cd4 #cgb ,hannig 7#ih74 #cgc ,young and ,kidston 7#hh7 ,a4 #cgd ,potoni 7#ja7 fig4 #gb1 p4 #aag4 #cge ,stur 7#ge7 ,,ii4 ,a4 ,pl4 ,,xxxvi4 fig4 #i4 #cgf ,see ,chap4 ,,xvii4 #cgg ,williamson 7#gb7 ,pl4 ,,xliv4 p4 #bid3 7#ic7 7#ic74 #cgh ,kidston 7#ja7 p4 #fj4 ,see also ,scott 7#jj7 p4 #agj1 figs4 #fg1 #fh4 #cgi ,williamson 7#ic71 ,pl4 ,,viii4 figs4 #ea1 #eb4 ,see also figs4 #fg-fi given by ,scott 7#jj74 #chj ,scott 7#jj7 p4 #agc4 #cha ,scott 7#jh7 p4 #ahg suggests that the projection may have formed a passage for the admission of the microspores1 or of the spermatozoids which they produced4 #chb ,bennie and ,kidston 7#hh7 ,pl4 ,,vi4 figs4 #bj1 a-s4 #chc ,gordon 7#jh74 #chd ,williamson 7#gb74 #che ,carruthers 7#fi74 #chf ,zeiller 7#ie74 ,see also ,white 7#jh7 p4 #ddg4 #chg ,arber 7#je7 ,pl4 ,i4 fig4 #b4 #chh ,seward and ,leslie 7#jh74 #chi ,zeiller 7#ih74 #cij ,renault 7#ij74 #cia ,seward 7#jg74 #cib ,nathorst 7#jg72 ,bather 7#jg72 7#jh74 #cic ,seward 7#ig7 ,a4 p4 #cbf1 ,pl4 ,,xxiii4 #cid ,carruthers 7#gb74 #cie ,unger and ,richter 7#ef74 #cif ,dawson 7#ga7 ,a4 ,pl4 ,,viii4 ,see also ,smith and ,white 7#je74 #cig ,m',coy 7#gd74 ,see also ,feistmantel 7#ij7 ,a4 #cih ,kidston 7#hf7 ,a4 p4 #bca4 #cii ,krasser 7#jj7 ,pl4 ,,ii4 fig4 #a4 #djj ,nathorst 7#id7 ,a4 ,pl4 ,,ii4 fig4 #h4 #dja ,szajnocha 7#ia7 p4 #bjc4 #djb ,see ,etheridge 7#ij72 ,david and ,pittman 7#ic74 #djc ,white 7#jh74 #djd ,brongniart 7#bh7 ,a4 p4 #hg4 #dje ,parkinson 7#aa7 ,a4 ,pl4 ,,ix4 fig4 #a1 p4 #dbh4 #djf ,carruthers 7#fi74 #djg ,brongniart 7#bb7 ,a4 ,pl4 ,,ii4 fig4 #d4 #djh ,bower 7#jh7 p4 #cje4 #dji ,seward 7#ij72 ,potoni 7#ic74 #daj ,brongniart 7#cg7 ,pl4 ,,xxiv4 #daa ,morris 7#dj7 ,pl4 ,,xxxviii4 fig4 #aj4 #dab ,williamson 7#ic7 ,pl4 ,,vi4 fig4 #bf1 ,a4 #dac ,kidston 7#ja7 p4 #fb4 #dad ,renault and ,zeiller 7#hh7 ,a4 ,pl4 ,,lxi4 fig4 #d4 #dae ,hooker 7#dh74 #daf ,binney 7#ga74 #dag ,williamson 7#ic7 p4 #bf4 #dah ,maslen 7#ii74 #dai ,lindley and ,hutton 7#cg7 ,a4 ,pl4 #afc4 #dbj ,for a detailed account of this type1 see ,maslen 7#ii74 #dba ,williamson 7#ic7 p4 #bh4 #dbb ,binney 7#ga74 #dbc ,binney 7#ga7 ,pl4 ,,viii4 figs4 #b1 #d4 #dbd ,maslen 7#ii7 ,pl4 ,,xxxvi fig4 #aa4 #dbe ,brown1 ,r4 7#ea74 #dbf ,brongniart 7#fh74 #dbg ,schimper 7#gj7 ,a4 p4 #fg1 ,pl4 ,,lxii4 figs4 #ac-bi4 #dbh ,bower 7#ic74 #dbi ,bower 7#id7 ,pl4 ,,xlviii4 fig4 #ic4 #dcj ,zeiller 7#ji74 #dca ,zalessky has recently 7#jh7 described a large species of cone1 ,lepidostrobus ,bertrandi1 #e cm4 in diameter4 #dcb ,morris 7#dj74 #dcc ,balfour 7#eg74 #dcd ,kidston and ,bennie 7#hh74 #dce ,reinsch 7#ha7 ,a4 #dcf ,scott1 ,r4 7#jf74 #dcg ,maslen 7#ii7 p4 #cgc2 ,scott1 ,r4 7#jf7 p4 #aag4 #dch ,campbell 7#je7 p4 #dad4 #dci ,williamson 7#gh7 ,a4 p4 #cdj1 ,pl4 ,,xxii4 ,see also the drawings in ,williamson's later papers quoted in the synonymy4 #ddj ,williamson 7#ic74 #dda ,scott1 ,d4 ,h4 7#ih74 #ddb ,berridge 7#je74 #ddc ,lang 7#jh74 #ddd ,lang 7#jh7 p4 #cfd4 #dde ,williamson 7#gh7 ,a4 ,pl4 ,,xxii4 fig4 #ec4 #ddf ,lang 7#jh7 p4 #cfg4 ,since this was written a paper has been published by ,mr ,watson on a new type of ,lycopodiaceous cone from the ,lower ,coal-,measures 7,mesostrobus73 in an appendix he criticises ,dr ,lang's views in regard to ,spencerites4 ,watson1 ,annals of ,botany1 ,vol4 ,,xxiii4 p4 #cgi1 #aiji4 #ddg ,seward and ,ford 7#jf7 p4 #cie4 #ddh ,artis 7#be7 ,a4 ,pl4 ,,xv4 #ddi ,rhode 7#bj74 #dej ,brongniart 7#bb7 ,a4 ,pl4 ,,xii4 fig4 #d4 #dea ,for generic names wholly or in part synonymous with ,sigillaria1 see ,white 7#ii7 p4 #bcj4 #deb ,kidston 7#hf7 ,a4 p4 #ahf4 #dec ,brongniart 7#cg7 ,pl4 ,,cl4 fig4 #a4 #ded ,brongniart 7#bb7 ,a4 ,pl4 ,,xii4 fig4 #c4 #dee ,sternberg 7#bc7 ,a4 #def ,goldenberg 7#ee74 #deg ,zeiller 7#hh7 ,a4 7,s4 elegans74 #deh ,goldenberg 7#ee74 #dei ,renault 7#if7 ,a4 ,pl4 ,,xxxv4 #dfj ,stur 7#ge7 ,,ii4 ,a4 ,pl4 ,,xlii4 #dfa ,for an account of the various external features made use of in the classification of ,sigillarias1 see ,koehne 7#jd74 #dfb ,grand',eury 7#ij7 ,a4 #dfc ,germar 7#ec74 #dfd ,cf4 ,lepidodendron ,zeilleri1 ,zalessky 7#jd7 ,pl4 ,,iv4 fig4 #a4 #dfe ,lesquereux 7#gi7 ,a4 ,pl4 ,,lxiv4 #dff ,zeiller 7#hh7 ,a4 ,pl4 ,,lxxi4 #dfg ,kidston 7#ja7 p4 #df4 #dfh ,kidston 7#he74 #dfi ,white1 ,d4 7#jg74 #dgj ,weiss1 ,c4 ,e4 7#hh74 #dga ,zeiller 7#hi74 #dgb ,kidston 7#ja7 p4 #id4 #dgc ,seward 7#ij74 #dgd ,weiss1 ,c4 ,e4 7#hi74 #dge ,grand',eury 7#ij7 ,a4 #dgf ,kidston 7#ig7 p4 #df4 #dgg ,grand',eury 7#ij7 ,a4 ,pl4 ,,xiii4 fig4 #h4 #dgh ,renault and ,roche 7#ig74 #dgi ,coward 7#jg72 ,renault 7#if7 ,a4 #dhj ,grand',eury 7#ij7 ,a4 ,pl4 ,,iii4 #dha ,cf4 ,prof4 ,yapp's account 7#jh7 of ,fen vegetation4 #dhb ,zeiller 7#hh7 ,a4 ,pl4 ,,lxxxv4 #dhc ,brongniart 7#bh7 ,a4 p4 #fc4 #dhd ,brongniart 7#ci7 ,a42 7#di7 ,a4 p4 #ee4 #dhe ,williamson 7#hc74 #dhf ,williamson 7#gb7 p4 #bbh4 #dhg ,renault 7#gi74 #dhh ,goldenberg 7#ee7 p4 #bd4 #dhi ,schimper 7#gj7 ,a4 p4 #aje4 #dij ,zeiller 7#hd74 #dia ,zeiller 7#hh7 ,a4 #dib ,kidston 7#ig74 #dic ,grand',eury 7#ij7 ,a4 ,vol4 ,,ii4 #did ,kidston 7#ig74 #die ,renault 7#if7 ,a4 #dif ,kidston 7#he74 #dig ,lindley and ,hutton 7#ca7 ,a4 ,pl4 ,,vi4 #dih ,thompson 7#hj74 #dii ,kidston 7#he7 ,pl4 ,,vi4 fig4 #aj4 #ejj ,kidston 7#hi7 p4 #fa2 ,pl4 ,,vi4 fig4 #a4 #eja ,zeiller 7#hh7 ,a4 p4 #dhc1 ,pls4 ,,lxxiii4 ,,lxxiv4 #ejb ,zeiller 7#jf7 ,pl4 ,,xlii4 #ejc ,kidston 7#jg74 #ejd ,renault 7#if7 ,a4 ,pl4 ,,xxxvii4 fig4 #c4 #eje ,renault 7#gi7 ,pls4 ,,xii4 ,,xiii4 p4 #bgj2 7#if7 ,a4 p4 #bde4 #ejf ,scott1 ,d4 ,h4 7#jd74 #ejg ,scott 7#jh7 p #bcj1 fig4 #ie4 #ejh ,kidston 7#jg74 #eji ,arber and ,thomas 7#jh74 #eaj ,goldenberg 7#ee72 ,kidston 7#ig74 #eaa ,zeiller 7#hh7 ,a4 ,pl4 ,,xc4 #a1 p4 #eih4 #eab ,zeiller 7#hd72 7#hh7 ,a4 ,pl4 ,,lxxxix4 #eac ,kidston 7#ig7 ,pls4 ,i4 ,,ii4 p4 #ej4 #ead ,goldenberg 7#ee74 #eae ,kidston 7#je7 ,pl4 ,,iii4 figs4 #bc1 #be1 #bf1 #bg4 #eaf ,zeiller 7#jf7 p4 #afj4 #eag ,brongniart 7#ci72 ,renault 7#if7 ,a4 #eah ,zeiller 7#hh7 ,a4 p4 #ehf2 ,kidston 7#je7 p4 #ecd4 #eai ,renault and ,grand',eury 7#ge72 ,renault 7#if7 ,a4 #ebj ,germar 7#dd7 ,a4 #eba ,scott 7#jh7 p4 #bai4 #ebb ,solms-,laubach 7#ia7 ,a4 p4 #bec4 #ebc ,renault and ,grand',eury 7#ge7 ,pl4 ,i4 fig4 #e4 #ebd ,coward 7#jg74 #ebe ,renault 7#if7 ,a4 p4 #bcg1 ,pl4 ,,xxxviii4 figs4 #a-d4 #ebf ,kidston 7#je74 #ebg ,brongniart 7#bh7 ,a4 ,pls4 ,,cxlvi4 ,,clv4 ,,clviii4 #ebh ,bertrand 7#ii74 #ebi ,scott 7#jh7 p4 #bbg1 fig4 #ic4 #ecj ,kidston 7#jg74 #eca ,arber and ,thomas 7#jg74 #ecb ,williamson 7#gb74 #ecc ,scott 7#jh7 p4 #bbg4 #ecd ,mettenius 7#fj74 #ece e4g4 ,l4 ,wnschianum 7fig4 #aha1 ,b1 lt74 #ecf ,kidston 7#je7 p4 #edg4 #ecg ,scott1 ,d4 ,h4 7#jb74 #ech ,for fuller synonymy1 see ,kidston 7#hf7 ,a4 p4 #agi2 and ,zeiller 7#jf7 p #afj2 ,koehne 7#jd7 p4 #fb4 #eci ,renault 7#if7 ,a4 ,pl4 ,,xxxv42 ,zeiller 7#jf7 ,pl4 ,,xlii4 #edj ,grand',eury 7#ij7 ,a4 #eda ,zeiller 7#jf7 ,pl4 ,,xlii4 #edb ,renault 7#if7 ,a4 ,pls4 ,,xxxvii4 ,,xli4 #edc ,grand',eury 7#ij7 ,a4 ,pl4 ,,xi4 #edd ,zeiller 7#jf7 p4 #agf4 #ede ,goldenberg 7#ee7 ,pl4 ,,xii4 #edf ,renault 7#if7 ,a4 ,pl4 ,,xxxix4 #edg ,zeiller 7#ib7 ,a42 7#jf74 #edh ,potoni 7#if7 ,a4 #edi ,fontaine and ,white 7#hj74 #eej ,kidston 7#id7 p4 #beb4 #eea ,seward 7#ig7 ,a4 #eeb ,white 7#jh7 p4 #dej1 ,pl4 ,v4 fig4 #ab4 #eec ,potoni 7#ja74 #eed ,goeppert 7#fd7 ,a4 #eee ,goeppert1 loc4 cit4 #eef ,gresley 7#hi7 ,pl4 ,,ii4 #eeg ,steinhauer 7#ah7 ,a4 #eeh ,logan 7#db74 #eei ,potoni 7#ic74 #efj ,williamson 7#hg7 ,a4 #efa ,a similar example1 now in the ,bergakademie of ,berlin1 has been described by ,potoni 7#ij7 ,a42 see also a note on the ,german specimen by ,seward 7#ia74 #efb ,martin 7#ji7 ,a4 ,pl4 ,,xii4 #efc ,artis 7#be7 ,a4 #efd ,lindley and ,hutton 7#ch7 ,a4 ,pl4 ,,clxvi4 #efe ,for a fuller synonymy1 see ,kidston 7#jc7 p4 #geg4 #eff ,goldenberg 7#ee7 p4 #f4 #efg ,binney 7#dd7 p4 #afe4 #efh ,brongniart 7#bb7 ,a4 p4 #bbh4 #efi ibid4 7#di7 ,a4 p4 #def4 #egj ,artis 7#be7 ,a4 ,pl4 ,x4 #ega ,lindley and ,hutton 7#ca7 ,a4 ,pl4 ,,xxxi4 #egb ,goldenberg 7#ee74 #egc ,logan 7#db7 p4 #dib4 #egd ,binney 7#dd72 7#df74 #ege ,bowman 7#da74 #egf ,brown 7#de72 7#df72 7#dg72 7#di74 ,see also ,dawson 7#ff74 #egg ,hawkshaw 7#db74 #egh ,binney 7#df7 p4 #cic4 #egi ,brown 7#di74 ,this figure is reproduced by ,williamson 7#hg7 ,a4 p4 #af4 #ehj ,williamson 7#hg7 ,a4 p4 #c4 ,solms-,laubach 7#ia7 ,a4 p4 #bhd4 #eha ,mellor and ,leslie 7#jf74 #ehb ,goeppert 7#fd7 ,a4 p4 #aig1 ,pls4 #cd-cf4 #ehc ,renault 7#ha74 #ehd ,grand',eury 7#ij7 ,a4 #ehe ,solms-,laubach 7#id74 #ehf ,grand',eury 7#gg7 ,a4 p4 #aga4 #ehg ,for figures see ,grand',eury 7#hg7 ,a42 7#ij7 ,a4 #ehh ,kidston 7#jb7 ,pl4 ,,li4 fig4 #d4 #ehi ,british ,museum1 ,no4 #hgj ,f4 #eij ,grand',eury 7#ij7 ,a4 #eia ,solms-,laubach 7#id74 #eib ,williamson 7#ib74 #eic ,thomas1 ,e4 ,n4 7#je7 p4 #ahg4 #eid ,williamson 7#hg7 ,a4 #eie ,solms-,laubach 7#ib74 #eif ,renault 7#if7 ,a4 ,pl4 ,,xl4 fig4 #e4 #eig ,weiss1 ,f4 ,e4 7#jh74 #eih ,williamson 7#hi7 ,a4 #eii ,renault 7#if7 ,a4 #fjj ,williamson 7#hg7 ,a4 ,pl4 ,,iv4 fig4 #bj4 #fja ,weiss1 ,f4 ,e4 7#jb74 #fjb ,hooker 7#dh7 ,pls4 ,i4 ,,ii4 ,the sections of ,stigmaria figured by ,hooker are in the ,british ,museum 7,v4 #hged74 #fjc ,williamson 7#hg7 ,a4 ,pl4 ,,xii4 #fjd ,solms-,laubach 7#ia7 ,a4 #fje ,weiss1 ,f4 ,e4 7#jb74 #fjf ,weiss1 ,f4 ,e4 7#jd74 #fjg ,goeppert 7#da7 ,pl4 ,x4 ,lief4 ,i4 ,,ii42 ,williamson 7#hg7 ,a4 ,pl4 ,,xiii4 fig4 #gh2 ,eichwald 7#fj7 ,pl4 ,,xv42 ,kidston 7#id7 p4 #bed4 #fjh ,goldenberg 7#ee7 ,pl4 ,,vi4 figs4 #a-d4 #fji ,nathorst 7#id7 ,a4 ,pl4 ,,xvi4 fig4 #i4 #faj ,watson 7#jh74 #faa ,zeiller 7#hh7 ,a4 ,pl4 ,,lxxvii4 fig4 #a4 #fab ,cf4 ,lindley and ,hutton 7#ce7 ,a4 ,pls4 #hj1 #ha4 #fac ,kidston 7#hf7 ,a4 p4 #age4 #fad ibid4 7#hf7 p4 #fe4 #fae ,haughton 7#ei74 #faf ,weiss1 ,c4 ,e4 7#hd7 ,pl4 ,,vi4 figs4 #f1 #g4 #fag ,lindley and ,hutton 7#ce7 ,a4 ,pls4 #hj1 #ha4 ,for synonymy1 see ,kidston 7#ic7 p4 #cdd4 #fah ,zeiller 7#hf7 ,pl4 ,,ix4 figs4 #a-c4 #fai ,no4 #ebebd4 #fbj ,nathorst 7#jb7 ,pl4 ,x4 figs4 #d1 #e4 #fba ,weiss1 ,f4 ,e4 7#jh74 #fbb ,schimper 7#gj7 ,a4 p4 #ga4 #fbc ,heer 7#ga7 ,pl4 ,,vi4 fig4 #aa2 ,pl4 ,,ix4 fig4 #a4 #fbd ,nathorst 7#id7 ,a4 p4 #fg1 ,pl4 ,,xv4 figs4 #ad1 #ae4 #fbe ,schmalhausen 7#gg7 p4 #bha1 ,pl4 ,i4 fig4 #e4 #fbf ,kidston 7#hi7 ,pl4 ,,iv4 figs4 #b-d1 p4 #fe4 #fbg ,weiss and ,sterzel 7#ic7 p4 #ef4 #fbh ,kidston 7#jc7 p4 #hbc4 #fbi ,schmalhausen 7#gg7 p4 #bij1 ,pl4 ,i4 figs4 #g-ab4 #fcj ,dawson 7#ga7 ,a4 ,pl4 ,,viii4 #fca ,weiss1 ,c4 ,e4 7#hd7 ,pl4 ,,vii4 #fcb ,potoni 7#ja7 figs4 #be-bg4 #fcc ,nathorst 7#jb7 p4 #ce4 #fcd ,seward 7#jc7 ,pl4 ,,xi4 figs4 #a-f1 p4 #hg2 ,arber 7#je7 p4 #aff4 #fce ,seward 7#ji74 #fcf ,feistmantel 7#ij7 ,a4 #fcg ,zeiller 7#hj7 ,a4 #fch ,trautschold and ,auerbach 7#fj7 ,pl4 ,,iii4 #fci ,zeiller 7#hb7 ,a42 7#hf74 #fdj ,nathorst 7#id7 ,a4 ,pls4 ,x4 ,,xi4 #fda ,volume ,i4 p4 #acd4 #fdb ,williamson 7#hi7 ,a4 p4 #aig4 #fdc ,i am indebted to ,mr ,lomax for photographs of his specimens4 ,for former references to ,mr ,lomax's discovery1 see ,kidston 7#je72 ,weiss1 ,f4 ,e4 7#jh72 ,scott ,d4 ,h4 7#jh7 p4 #bjj4 #fdd ,williamson 7#hi7 ,a4 #fde ,weiss1 ,f4 ,e4 7#jh74 #fdf ,nathorst 7#id7 ,a4 p4 #db4 #fdg ,williamson 7#hj7 ,a4 p4 #ejj1 ,pl4 ,,xv4 #h4 #fdh ,watson 7#jh7 p4 #ab4 #fdi ,nathorst 7#id7 ,a4 p4 #db1 ,pl4 ,,xii4 figs4 #h-aj4 #fej ,kidston 7#jc7 p4 #gig4 #fea ,white 7#ih72 7#ii7 p4 #bah1 ,pls4 ,,lxv4-,,lxviii4 #feb ,kidston 7#jb7 pp4 #ceh1 #cei4 #fec ,tansley and ,chick 7#ja7 p4 #cf4 #fed ,kidston 7#je7 p4 #edg4 #fee ,renault 7#if7 ,a4 #fef ,weiss1 ,f4 ,e4 7#jh74 #feg ,browne 7#ji7 p4 #be4 #feh ,scott 7#jb7 uses the terms old and new wood in discussing the evolutionary sequence in plant steles4 #fei ,white 7#jg74 #ffj ,bower 7#jh7 p4 #cje4 #ffa ,browne 7#ji7 p4 #cg4 #ffb ,williamson 7#gg7 and 7#hj7 ,a4 #ffc ,brongniart 7#bh7 ,a4 p4 #hg4 #ffd ,carruthers 7#gb74 #ffe ,wild and ,lomax 7#jj74 #fff ,scott 7#ja74 #ffg ,letter from ,d4 ,h4 ,scott 7,march #cj1 #aijh74 #ffh ,scott 7#ja7 #cad4 #ffi ,seward and ,ford 7#jf74 #fgj ,for a contrary opinion1 see ,scott 7#ji7 p4 #fef4 #fga ,bertrand1 ,e4 7#id74 #fgb ,benson 7#jh74 #fgc ,watson 7#jh7 p4 #ab4 #fgd ,ward 7#jd74 #fge ,tansley 7#jh7 p4 #c4 ,cf4 ,braun 7#ge7 p4 #bfg4 #fgf ,chodat 7#jh74 #fgg ,hudson 7#ib7 p4 #bi4 #fgh ,hardy1 ,return of the ,native1 ,,ii4 p4 #aec4 #fgi ,bower 7#jh74 #fhj ,zeiller 7#jf7 p4 #h4 #fha ,engler 7#ji74 #fhb ,bower 7#jj74 #fhc ,for an account of the mechanism of spore-dispersal1 see ,goebel 7#je7 p4 #ehg2 ,atkinson 7#id72 ,leclerc du ,sablon 7#he72 and ,bower 7#jj74 #fhd ,for a fuller account of recent ferns1 see ,engler and ,prantl 7#jb71 ,christ 7#ig71 ,hooker and ,baker 7#fh71 and ,bower 7#jj7 7#jh74 #fhe ,prantl 7#ha7 ,pl4 ,,vii4 fig4 #ajd1 ,c2 ,zeiller 7#ig7 p4 #bae1 figs4 #g-aj4 #fhf ,underwood 7#jg71 p4 #bdc1 has adopted ,bernhardi's genus ,dicranopteris in place of ,mertensia on the ground that the latter was used as early as #agic for a ,boraginaceous plant4 #fhg ,goebel 7#je7 p4 #cah4 #fhh ,baker 7#hh74 #fhi ,diels1 in ,engler and ,prantl 7#jb7 pp4 #cdc1 #cdd4 #fij ,compton 7#ji74 #fia ,copeland 7#jh7 p4 #cdd4 #fib ,bower 7#jj7 p4 #dg2 ,gwynne-,vaughan 7#ja74 #fic ,christ 7#jd74 #fid ,scott1 ,j4 7#gd72 ,hannig 7#ih74 #fie ,challenger ,reports 7#he7 p4 #hbg4 7,narrative1 ,pl4 ,,ii47 #fif ,bower 7#jj7 p4 #fh4 #fig ,diels 7#jb7 p4 #aag4 #fih ,seward 7#ib7 p4 #de4 #fii ,bower 7#jj7 p4 #hj4 #gjj ,prof4 ,bower informs me that he is now at work on ,plagiogyria and other ,polypodiaceae4 #gja ,kny 7#ge72 ,ford 7#jb72 ,goebel 7#ia74 #gjb ,seward and ,dale 7#ja74 #gjc ,armour 7#jg74 #gjd ,diels 7#jb7 fig4 #ih1 p4 #ahh4 #gje ,giesenhagen 7#ib7 p4 #agi1 fig4 #c4 #gjf ,bsecke 7#jh74 #gjg ,boodle 7#jj74 #gjh ,yapp 7#jb74 #gji ,darwin 7#jc7 ,,ii4 p4 #cha4 #gaj ,reinecke 7#ig74 #gaa ,karsten 7#ie72 ,christ 7#if72 ,bommer 7#jc74 #gab ,goebel 7#je7 p4 #cdg4 #gac ,a striking example of these so-called ,aphlebiae of ,hemitelia may be seen at the ,royal ,gardens1 ,kew4 #gad ,luerssen1 in ,rabenhorst 7#hi7 ,a4 p4 #dhc1 fig4 #afd4 #gae ,goebel 7#ja7 ,pl4 ,,xiii4 #gaf ,spruce 7#jh7 ,,ii4 p4 #bcb4 #gag ,boodle 7#jd74 #gah ,goebel 7#je72 ,baker 7#fg74 #gai ,seward and ,gowan 7#jj74 #gbj ,hooker 7#ei74 #gba ,thiselton-,dyer 7#je74 #gbb ,baker 7#fh7 p4 #cje4 #gbc ,bower 7#jh7 p4 #ah4 #gbd ,treub 7#hh7 ,a42 ,ernst 7#jh74 #gbe ,campbell 7#jg74 #gbf ,davy 7#jg7 p4 #bfc4 #gbg ,bates 7#fc7 ,a4 p4 #cj4 #gbh ,challenger ,reports 7#he7 p4 #ghe4 #gbi ,tansley and ,fritsch 7#je7 p4 #dc2 ,thomas1 ,e4 ,n4 7#je74 #gcj ,tansley 7#jh7 p4 #bg4 #gca ,jeffrey 7#ih74 #gcb ,boodle 7#jj74 #gcc ,tansley and ,lulham 7#jb74 #gcd ,gwynne-,vaughan 7#ja72 7#jc74 #gce ,boodle 7#ja7 p4 #gce4 #gcf ,jeffrey 7#jj72 7#jc74 #gcg ,for an account of the probable methods by which this has been effected and of the factors concerned1 see ,tansley 7#jh74 #gch ,gwynne-,vaughan 7#jc74 #gci ,seward 7#ii72 ,wigglesworth 7#jb74 #gdj ,seward and ,ford 7#jc72 ,jeffrey 7#jc72 ,faull 7#ja74 #gda ,kidston and ,gwynne-,vaughan 7#jg72 7#jh72 7#ji74 #gdb ,gwynne-,vaughan 7#jh74 #gdc ,bertrand and ,cornaille 7#jb74 #gdd ,chodat 7#jh7 p4 #ae4 #gde ,see also ,pelourde 7#ji7 for an account of the anatomy of fern petioles4 #gdf ,observed in plants in the ,botanic ,gardens of ,brussels and ,leipzig4 ,a4,c4,s4 #gdg ,for an account of the spore-producing members of the ,marattiaceae1 see ,bower 7#ig74 #gdh ,zeiller 7#ij7 p4 #ai4 #gdi ,shove 7#jj72 ,tansley 7#jh74 #gej ,farmer and ,hill 7#jb7 ,pl4 ,,xviii4 figs4 #bf1 #bh4 #gea ,christ and ,giesenhagen 7#ii74 #geb ,gwynne-,vaughan 7#je74 #gec ,hooker and ,baker 7#fh7 p4 #ddj4 #ged ,the term synangium is applied to sporangia more or less completely united with one another and producing spores in groups separated by walls of sterile cells4 ,a synangium may be regarded as a spore-forming organ produced by partial sterilization of sporogenous tissue or as a group of coalescent sporangia4 #gee ,brebner 7#jb72 ,rudolph 7#je74 #gef ,tansley 7#jh7 p4 #ij2 ,khn 7#ij74 #geg ,pelourde 7#jh7 has recently dealt with the anatomy of recent and fossil ,marattiaceous ferns4 #geh ,copeland 7#jh7 ,pl4 ,i4 7#ji7 ,pl4 ,v4 #gei ,bower 7#if74 #gfj ,jeffrey 7#ih74 ,for an account of the anatomy of ,helminthostachys1 see ,farmer and ,freeman 7#ii74 #gfa ,stur 7#ge7 ,a4 p4 #gg1 ,pl4 ,,xi4 fig4 #h4 #gfb ,renault 7#if7 ,a4 p4 #ba4 #gfc ,zeiller 7#ij7 p4 #af4 #gfd ,zeiller 7#ij7 p4 #dh4 #gfe ,scott1 ,d4 ,h4 7#jh7 p4 #bib4 #gff ,scott 7#jd7 p4 #ah4 #gfg ,boodle 7#jj7 p4 #dhd4 #gfh ,zeiller 7#ii7 ,pl4 ,,ii4 figs4 #e1 #f4 #gfi ,ibid4 ,pl4 ,,ii4 fig4 #aj4 #ggj ,see p4 #djb4 #gga ,bower 7#ia7 ,pl4 ,,vii4 #ggb ,scott1 ,d4 ,h4 7#ji74 #ggc ,kidston and ,gwynne-,vaughan 7#jh74 #ggd ,eichwald 7#fj74 #gge ,gwynne-,vaughan 7#jh74 #ggf ,kidston and ,gwynne-,vaughan 7#jh7 p4 #bbf4 #ggg ,brongniart 7#di7 ,a4 p4 #ce4 #ggh ,brongniart 7#bh7 ,a4 ,pl4 ,,lxxx4 #ggi ,kidston and ,gwynne-,vaughan 7#ji74 #ghj ,seward 7#ii74 #gha ,krasser 7#ji7 p4 #aj4 #ghb ,fontaine 7#hc7 ,pls4 ,,xxviii4 ,,xxix4 #ghc ,leuthardt 7#jd7 ,pl4 ,,xviii4 #ghd ,kidston and ,gwynne-,vaughan 7#jg74 #ghe ,see p4 #cdc4 #ghf ,seward and ,ford 7#jc74 #ghg ,kidston and ,gwynne-,vaughan 7#jg74 #ghh ,seward 7#jg7 p4 #dhb1 ,pls4 ,,xx4 ,,xxi4 #ghi ,seward 7#jc72 ,kitchin 7#jh74 #gij ,cf4 ,todea ,wilkesiana 7p4 #bhf74 #gia ,penhallow 7#jb74 #gib ,kidston and ,gwynne-,vaughan 7#jg74 #gic ,see p4 #cad4 ,also ,jeffrey 7#jc72 ,faull 7#ja72 ,seward and ,ford 7#jc74 #gid ,raciborski 7#id7 ,a4 p4 #ai1 ,pls4 ,,vi4 ,,xi4 #gie ,carruthers 7#gj7 ,a42 ,kidston and ,gwynne-,vaughan 7#jg7 p4 #gfh2 see also ,seward1 ,vol4 ,i4 p4 #bab4 #gif ,gardner and ,ettingshausen 7#hb7 pp4 #bb1 #dh1 ,pl4 ,,iv4 figs4 #a-c4 #gig ,seward 7#jj7 p4 #hf4 #gih ,seward and ,ford 7#jc7 p4 #bea4 #gii ,for a more complete list1 see ,seward 7#jj7 p4 #hg4 #hjj ,schenk 7#he7 ,pl4 ,,iii4 fig4 #c4 #hja ,raciborski 7#id7 ,a4 ,pl4 ,,vi4 #hjb ,nathorst 7#jh7 ,pl4 ,i4 fig4 #g4 #hjc ,schenk 7#fg7 ,a4 #hjd ,fontaine 7#hc74 #hje ,the geographical distribution of ,todites and other genera will be dealt with in ,volume ,,iii4 #hjf ,carruthers 7#gj7 ,a4 p4 #cej4 #hjg ,reid 7#ii74 #hjh ,seward 7#jh7 ,pl4 ,,viii4 p4 #ih4 #hji ,zeiller 7#jc7 ,pls4 ,,ii4 ,,iv4 #haj ,leuthardt 7#jd7 ,pl4 ,,xv4 #haa ,fontaine 7#hc7 ,pls4 ,,xi4-,,xiv4 #hab ,for synonymy and figures1 see ,seward 7#jj7 p4 #acd2 7#jd7 p4 #acd4 #hac ,e4g4 by ,yokoyama 7#jf7 who identifies specimens of ,cladophlebis denticulata from ,jurassic rocks of ,china as ,todites ,williamsoni4 #had ,lindley and ,hutton 7#cd7 ,a4 ,pl4 ,,cxxxiv4 #hae ,seward 7#id7 ,a4 p4 #ia4 #haf ,nathorst 7#gh74 #hag ,lindley and ,hutton 7#cd7 ,a4 ,pl4 ,,cxx4 #hah ,fontaine1 in ,ward 7#je7 ,pl4 ,,xv4 figs4 #f-i74 #hai ,feistmantel 7#gg7 ,pls4 ,,xxxvi4 ,,xxxvii4 #hbj ,morris 7#de7 ,pl4 ,,vii4 #hba ,renault 7#hc7 p4 #ha1 ,pl4 ,,xi4 #hbb ,dawson 7#fa74 #hbc ,white 7#jd74 #hbd ,corda 7#de7 ,a4 ,pl4 ,,lvii4 #hbe ,zeiller 7#hc7 p4 #ahh1 ,pl4 ,x4 figs4 #a-e4 #hbf ,stur 7#he7 ,a4 p4 #fd4 #hbg ,zeiller 7#hh7 ,a4 p4 #ej4 #hbh ,solms-,laubach 7#ia7 ,a4 p4 #adg4 #hbi ,for synonymy1 see ,seward 7#jj7 p4 #acj4 #hcj ,raciborski 7#ia74 #hca ,phillips 7#bi7 ,a4 p4 #adh4 #hcb ,bunbury 7#ea7 ,a4 #hcc ,seward 7#id7 ,a4 #hcd ,raciborski 7#id7 ,a4 #hce ,yokoyama 7#hi74 #hcf ,seward 7#id7 ,a4 #hcg ,yabe 7#je7 ,pl4 ,,iii4 #hch ,seward 7#jg7 ,pls4 ,i4 ,,iii4 #hci ,seward 7#id7 ,a4 p4 #ge4 #hdj ,gardner and ,ettingshausen 7#hb7 p4 #dg1 ,pls4 ,,vii4 ,x42 ,heer 7#ee7 ,a4 ,pl4 ,,iii4 p4 #da4 #hda ,knowlton 7#ii74 ,pl4 ,,lxxx4 #hdb ,heer 7#ee7 ,a4 ,pl4 ,,xiii4 #hdc ,saporta 7#gb7 ,a4 ,pl4 ,i4 figs4 #ac1 #ad4 #hdd ,goeppert 7#cf7 ,a4 ,pls4 ,,iv4 ,v4 #hde ,zeiller 7#hh7 ,a4 p4 #bfa4 #hdf ,williamson 7#gg7 ,pl4 ,,vii4 #hdg ,see ,ch4 ,,xxvii4 #hdh ,goeppert 7#da7 ,pl4 ,,iv4 figs4 #a1 #b4 #hdi ,zeiller 7#hh7 ,a4 ,pl4 ,,xi4 figs4 #c-e4 #hej ,stur 7#he7 ,a4 p4 #abh4 #hea ,solms-,laubach 7#ia7 ,a4 p4 #adf4 #heb ,schenk 7#hh7 ,a4 p4 #cj4 #hec ,dr ,scott tells me that an examination of ,dr ,zeiller's specimens led him to agree with the latter's description of the annulus of ,oligocarpia4 7,a4 ,c4 ,s47 #hed ,fontaine 7#hc7 ,pls4 ,,xv4-,,xix4 #hee ,bunbury 7#dg7 ,pl4 ,,ii4 fig4 #a2 ,seward 7#id7 ,a4 p4 #ahi4 #hef ,krasser 7#ji7 p4 #af4 #heg ,leuthardt 7#jd7 p4 #dj1 ,pl4 ,,xviii4 fig4 #c4 #heh ,schenk 7#fg7 ,a4 p4 #hf1 ,pl4 ,,xxii4 figs4 #g1 #h4 #hei ,zigno 7#ef7 ,a4 ,pl4 ,x4 #hfj ,raciborski 7#id7 ,a4 p4 #dc1 ,pl4 ,,xiii4 figs4 #ae-bj4 #hfa ,seward 7#ie7 ,a4 p4 #bbe4 #hfb ,seward 7#jj7 ,pl4 ,,iv4 #hfc ,schenk 7#ga74 #hfd ,corda1 in ,reuss 7#df7 p4 #ie1 ,pl4 ,,xlix4 #hfe ,heer 7#ge71 p4 #dd1 ,pls4 ,,iv4-,,vii4 #hff ,debey and ,ettingshausen 7#ei7 ,pl4 ,i4 #hfg ,gardner and ,ettingshausen 7#hb71 pp4 #dc1 #ei1 ,pls4 ,,vi4 ,x4 #hfh ,wanklyn 7#fi74 #hfi ,presl1 in ,sternberg 7#ch7 ,a4 p4 #aae4 #hgj ,schenk 7#fg7 ,a4 #hga ,zeiller 7#he74 #hgb ,seward 7#ii7 p4 #aid4 #hgc ,schenk 7#fg7 ,a4 ,pls4 ,,xxiii4 ,,xxiv4 #hgd ,for a more complete list1 see ,seward 7#jj7 p4 #gh4 #hge ,leckenby 7#fd7 ,a4 p4 #ha1 ,pl4 ,,viii4 fig4 #f4 7,type-specimen in the ,sedgwick ,museum1 ,cambridge47 #hgf ,saporta 7#gc7 ,a4 p4 #cjf4 #hgg ,debey and ,ettingshausen 7#ei7 ,pl4 ,,iii4 #hgh ,see ,seward 7#id7 ,a4 and 7#jj7 for an account of this fern4 #hgi ,schenk 7#ga7 p4 #bai4 #hhj ,zeiller 7#he74 #hha ,ettingshausen 7#eb7 p4 #af1 ,pl4 ,v4 ,for synonymy1 see ,seward 7#id7 ,a2 7#jj74 #hhb ,fontaine1 in ,ward 7#je7 p4 #bcj4 #hhc ,schenk 7#ga7 p4 #ai4 #hhd ,fontaine1 loc4 cit4 ,pl4 ,,lxv4 figs4 #bb1 #bc4 #hhe ,krasser 7#if7 p4 #aai1 ,pls4 ,,xi4 ,,xii4 ,,xiv4 #hhf ,stur 7#ge7 ,a4 p4 #bhd1 ,pl4 ,,xxxiii4 fig4 #ae4 #hhg ,renault 7#if7 ,a4 p4 #ai4 #hhh ,ettingshausen 7#ff7 ,pl4 ,,vii4 fig4 #d4 #hhi ,stur 7#ge7 ,a4 p4 #cf1 ,pl4 ,,ix4 figs4 #a-i4 #hij ,schimper 7#gd7 ,a4 ,pl4 ,,xxviii4 fig4 #d-g4 #hia ,solms-,laubach 7#ia7 ,a4 p4 #aec4 #hib ,zeiller 7#hc7 p4 #aee2 7#hh7 ,a4 ,pl4 ,,viii4 figs4 #a-c4 #hic ,kidston 7#hd7 p4 #eic4 #hid ,see p4 #dej4 #hie ,scott 7#jh7 p4 #cdc4 #hif ,stur 7#ge7 ,a4 p4 #ai1 ,pl4 ,x4 figs4 #a1 #b4 #hig ,goeppert 7#cf7 ,a4 pp4 #cai1 #cbj1 #cbi4 #hih ,sterzel 7#hf74 #hii ,grand',eury 7#je74 #ijj ,zeiller 7#jf7 ,pls4 ,,ii4 ,,iii4 #ija ,raciborski 7#id7 ,a4 ,pl4 ,,ix4 #ijb ,brongniart 7#di7 ,a4 p4 #bf4 #ijc ,krasser 7#ji74 #ijd ,for fuller synonymy see ,seward 7#jj7 p4 #ig4 #ije ,heer 7#gf74 #ijf ,fontaine 7#hi74 #ijg ,fontaine 7#hi7 p4 #abc1 ,pls4 ,,xxvi4 ,,xliii4 etc4 #ijh ,ward 7#ii7 ,pl4 ,,clxi4 #iji ,velenovsk 7#hh74 #iaj ,heer 7#ge7 ,a4 ,pl4 ,i4 figs4 #f1 #g4 #iaa ,heer 7#hb7 ,a4 ,pl4 ,,ii4 fig4 #b4 #iab ,phillips 7#ge7 ,a4 p4 #bae4 #iac ,seward 7#jj74 #iad ,sternberg 7#ch7 ,a4 p4 #afi4 #iae ,sternberg 7#bj7 ,a4 ,pl4 ,,iv4 #iaf ,corda 7#de7 ,a4 ,pl4 ,,ii4 fig4 #e4 #iag ,brongniart 7#bh7 ,a4 ,pl4 ,,xli4 #iah ,feistmantel 7#gb74 #iai ,velenovsk 7#hh74 #ibj ,carruthers 7#fe7 ,pl4 ,,xiii4 #iba ,heer 7#ge74 #ibb ,heer 7#hb7 ,pl4 ,,xlvii4 #ibc ,fri and ,bayer 7#ja7 p4 #gf4 #ibd ,stenzel 7#hf74 ,see also ,stenzel 7#ig74 #ibe ,gwynne-,vaughan 7#jh74 #ibf ,schenk 7#ga7 ,pl4 ,,xxx42 ,seward 7#id7 ,a4 ,pl4 ,,xi4 #ibg ,scott 7#jh7 p4 #bic4 #ibh ,goeppert 7#cj7 ,a4 p4 #bag4 #ibi ,schimper 7#fi7 ,a4 p4 #dbd4 #icj ,ettingshausen 7#ff74 #ica ,kidston 7#hi7 ,pl4 ,i4 #icb ,white 7#jd74 #icc ,schenk 7#fg7 ,a4 ,pl4 ,,xiii42 ,zeiller 7#jc7 p4 #ia1 ,pl4 ,,xvii4 #icd ,seward 7#jd7 p4 #afb1 ,pl4 ,,viii4 fig4 #e4 #ice ,yabe 7#je7 p4 #ci1 ,pl4 ,i4 figs4 #a-h4 #icf ,fontaine1 in ,ward 7#je7 p4 #fd4 #icg ,yokoyama 7#hi71 p4 #bf4 #ich ,geyler 7#gg7 ,pl4 ,,xxxi4 fig4 #d4 #ici ,for synonymy1 see ,fontaine1 in ,ward 7#je7 p4 #aee2 ,richter 7#jf7 p4 #f2 ,seward 7#id7 ,a4 p4 #da2 7#jc7 p4 #e4 #idj ,seward 7#id7 ,a4 p4 #eb4 #ida ,gardner and ,ettingshausen 7#hb7 ,pls4 ,i4 ,,ii4 #idb ,forbes 7#ea72 ,gardner and ,ettingshausen 7#hb74 #idc ,knowlton 7#jb7 ,pl4 ,,xxvi4 #idd ,saporta 7#fh7 ,a42 ,gardner and ,ettingshausen 7#hb7 ,pl4 ,x4 fig4 #a4 #ide ,gardner and ,ettingshausen 7#hb7 p4 #ba4 #idf ,lindley and ,hutton 7#cd7 ,a4 ,pl4 ,,civ4 #idg ,nathorst 7#jf74 #idh ,seward and ,dale 7#ja7 p4 #eje4 #idi ,zeiller 7#jc7 p4 #aji1 ,pls4 ,,xxiii4-,,xxviii4 #iej ,seward 7#jj7 p4 #abb4 #iea ,nathorst 7#jf74 #ieb ,krasser 7#ji7 p4 #aaa4 #iec ,goeppert 7#da74 #ied ,seward and ,dale 7#ja7 p4 #ejc4 #iee ,nathorst 7#jg74 #ief ,schenk 7#fg7 ,a4 ,pl4 ,,xviii4 #ieg ,zeiller 7#jc74 #ieh ,brongniart 7#be74 #iei ,brongniart 7#be74 #ifj ,zeiller 7#jc74 #ifa ,seward 7#jd7 pp4 #ah1 #afd4 #ifb ,seward 7#jg74 #ifc ,the evidence of the shells is stated by ,mr ,r4 ,b4 ,newton 7#ji7 to be in favour of the ,cretaceous age of the ,nubian ,sandstone4 #ifd ,nathorst 7#gh7 p4 #cc4 #ife ,nathorst 7#jf7 p4 #ae4 #iff ,richter 7#jf74 #ifg ,dunker 7#df7 ,a4 p4 #ab4 #ifh ,andrae 7#ec7 ,a4 #ifi ,zigno 7#ef7 ,a4 ,,ix4 fig4 #b4 #igj ,nathorst 7#gh7 ,pl4 ,,ix4 fig4 #b4 #iga ,zeiller 7#ig7 p4 #ea4 #igb ,seward and ,dale 7#ja74 #igc ,dunker 7#df7 ,a41 ,pl4 ,v4 fig4 #a4 #igd ,bartholin 7#ib7 ,pls4 ,,xi4 ,,xii4 #ige ,moeller 7#jb7 ,pls4 ,,iv4-,,vi4 #igf ,richter 7#jf7 p4 #ba4 #igg ,richter 7#jf7 p4 #bb4 #igh ,andrae 7#ec7 ,a4 #igi ,moeller 7#jb7 ,pls4 ,,iv4-,,vi4 #ihj ,nathorst 7#gh7 ,pl4 ,,ix4 fig4 #b4 #iha ,zeiller 7#gi74 #ihb ,gardner and ,ettingshausen 7#hb7 p4 #bi1 ,pl4 ,,iii4 fig4 #f4 #ihc ,arber 7#jf7 p4 #bbg4 #ihd ,scott 7#jf7 p4 #ahi4 #ihe ,zeiller 7#je74 #ihf ,kidston 7#jf74 #ihg ,kidston 7#jf7 p4 #dbi4 #ihh ,weiss1 ,c4 ,e4 7#fi7 p4 #id1 ,pl4 ,,xi4 fig4 #b4 ,the specimens figured by ,weiss bear a somewhat remote resemblance to that described by ,renault 7#if7 ,a1 under the same generic name4 #ihi ,kidston 7#ia7 p4 #bc4 #iij ,kidston 7#hh7 p4 #cej4 #iia ,renault 7#if7 ,a4 p4 #i2 ,zeiller 7#hh7 ,a4 p4 #afb2 ,grand',eury 7#gg7 ,a4 ,pl4 ,,viii4 fig4 #ac4 #iib ,watson 7#jf74 #iic ,goeppert 7#cf7 ,a4 p4 #chj4 #iid ,stur 7#he7 ,a4 p4 #bba1 ,pl4 ,,lxi42 ,zeiller 7#hh7 ,a4 p4 #da4 #iie ,grand',eury 7#ij7 ,a4 p4 #bhh1 ,pl4 ,,vi4 fig4 #bf4 #iif ,for an account of these genera1 see ,chap4 ,,xxvii4 #iig ,strasburger 7#gd74 #iih ,stur 7#he7 ,a4 p4 #ahc4 #iii ,corda 7#de7 ,a4 ,pl4 ,,lvii4 #ajjj ,kidston 7#ia7 p4 #bj2 ,stur 7#he7 ,a4 ,pl4 ,,lix4 #ajja ,see ,chap4 ,,xxvii4 #ajjb ,stur 7#he7 ,a4 p4 #ajf4 #ajjc ,zenker 7#cg74 #ajjd ,strasburger 7#gd74 #ajje ,kidston 7#ia7 p4 #bj4 #ajjf ,geinitz 7#gb74 ,see ,solms-,laubach 7#hc71 who gives in full the early history of the genus ,scolecopteris4 #ajjg ,sterzel 7#gh72 7#hj74 #ajjh ,stur 7#he7 p4 #adj4 #ajji ,zeiller 7#ii7 p4 #ag4 #ajaj ,zeiller 7#jf7 p4 #aj4 #ajaa ,brongniart 7#bh7 ,a4 ,pl4 ,,cxxv4 fig4 #d4 #ajab ,renault and ,zeiller 7#hh7 ,a4 ,pl4 ,,xxiv4 #ajac ,page #cbe4 #ajad ,zeiller 7#hc7 p4 #ahd2 7#hh7 ,a4 p4 #cj4 #ajae ,artis 7#be7 ,a4 #ajaf ,stur 7#ge7 ,a4 #ajag ,kidston 7#if7 p4 #bje4 #ajah ,zeiller 7#hc7 p4 #ahe4 #ajai ,kidston 7#hb74 #ajbj ,stur 7#he74 #ajba ,kidston 7#hd74 #ajbb ,kidston 7#hg74 #ajbc ,kidston 7#hb7 p4 #cb4 #ajbd ,kidston 7#hd7 p4 #eid4 #ajbe ,williamson 7#hc7 ,a4 #ajbf ,kidston 7#jf74 #ajbg ,heer 7#gf7 ,a4 p4 #ga1 ,pl4 ,,xxiv4 fig4 #a4 #ajbh ,schimper 7#gd7 ,a4 ,pl4 #ch2 see also ,schenk 7#hh7 ,a4 p4 #ca4 #ajbi ,leuthardt 7#jd7 p4 #bi1 ,pl4 ,,xiii4 figs4 #a1 #b4 #ajcj ,goeppert 7#cf7 ,a4 ,lief4 ,i4 and ,,ii4 ,pl4 ,,iv4 #ajca ,schimper 7#fi7 ,a4 p4 #fjg4 #ajcb ,schenk 7#hc7 ,a4 p4 #bfj4 #ajcc ,zeiller 7#jc7 ,pl4 ,,ix4 #ajcd ,fontaine1 in ,ward 7#jj7 ,pl4 ,,lv4 figs4 #c-e4 #ajce ,bartholin 7#ib7 ,pl4 ,,ix4 #ajcf ,moeller 7#jb74 #ajcg ,schenk 7#hc7 ,a4 #ajch ,seward 7#jg7 ,pl4 ,,ii4 figs4 #af-ah4 #ajci ,nathorst 7#jh74 #ajdj ,krasser 7#ji74 #ajda ,feistmantel 7#hb7 ,pls4 ,,iv4-,x4 #ajdb ,seward 7#jh7 p4 #ie4 #ajdc ,krasser 7#jj7 ,pl4 ,,ii4 #ajdd ,zeiller 7#jc7 ,pl4 ,,ix4 #ajde ,krasser 7#ji7 p4 #ba4 #ajdf ,leuthardt 7#jd7 ,pls4 ,,xix4 ,,xx4 #ajdg ,zigno 7#ef7 ,a4 ,pl4 ,,xxv4 #ajdh ,raciborski 7#id7 ,a4 ,pl4 ,,vi4 #ajdi ,heer 7#hj74 #ajej ,nathorst 7#jh74 #ajea ,bayer 7#ii74 #ajeb ,gardner and ,ettingshausen 7#hb7 ,pl4 ,,xii4 figs4 #a-g4 #ajec ,stenzel 7#ed7 p4 #hjc4 #ajed ,cotta 7#cb74 #ajee ,sprengel 7#bh74 #ajef ,stenzel 7#ed7 p4 #gec4 #ajeg ,parkinson 7#aa7 ,a4 #ajeh ,williamson 7#gf74 #ajei ,scott 7#jh74 #ajfj ,butterworth 7#jj74 #ajfa ,grand',eury 7#gg7 ,a4 #ajfb ,grand',eury 7#gg7 ,a2 7#ij7 ,a4 #ajfc ,rudolph 7#je74 #ajfd ,scott 7#jh7 p4 #cjb4 #ajfe ,butterworth 7#jj74 ,pelourde 7#jh7 has recently described the structure of the roots of several species of ,psaronius4 #ajff ,stenzel 7#jf74 #ajfg ,farmer and ,hill 7#jb74 #ajfh ,williamson 7#gf7 ,pl4 ,,iii4 #ajfi ,stenzel 7#hi7 ,pl4 ,,vi4 #ajgj ,zeiller 7#ij7 p4 #bjd1 ,pls4 ,,xvi4 ,,xvii42 see also ,rudolph 7#je74 #ajga ,renault and ,zeiller 7#hh7 ,a4 ,pls4 ,v4-,,viii4 #ajgb ,solms-,laubach 7#jd74 #ajgc ,arber 7#je7 ,pl4 ,,vii4 #ajgd ,scott 7#jh7 fig4 #aac2 ,zeiller 7#ij7 p4 #bdf1 ,pl4 ,,xxi4 fig4 #a4 #ajge ,pelourde 7#jh74 #ajgf ,stenzel 7#jf7 ,pl4 ,,vi42 ,goeppert 7#fd7 ,a42 ,stenzel 7#jf74 #ajgg ,zeiller 7#ij7 ,pl4 ,,xxiii4 #ajgh ,scott 7#jh7 p4 #cja4 #ajgi ,lindley and ,hutton 7#cc7 ,a4 ,pl4 ,,xlii4 #ajhj ,kidston 7#hh7 ,pl4 ,,xxvi4 #ajha ,renault and ,zeiller 7#hh7 ,a4 ,pl4 ,,xxxv4 fig4 #f4 #ajhb ,kidston 7#hf7 ,a4 p4 #aac4 #ajhc ,artis 7#be7 ,a4 ,pl4 ,,xx4 #ajhd ,lesquereux 7#ff7 ,a4 #ajhe ,renault and ,zeiller 7#hh7 ,a4 ,pl4 ,,xl42 ,grand',eury 7#ij7 ,a4 #ajhf ,corda 7#de7 ,a42 see also ,grand',eury 7#ij7 ,a42 ,renault and ,zeiller 7#hh7 ,a4 ,pls4 ,,xxxviii4-,,xl4 #ajhg ,fontaine and ,white 7#hj7 ,pl4 ,,xxxvi42 ,zeiller 7#ij7 ,pl4 ,,xiv4 #ajhh ,mettenius 7#fe72 ,tansley 7#jh7 p4 #he4 #ajhi ,rudolph 7#je74 #ajij ,scott1 ,d4 ,h4 7#jh74 #ajia ,shove 7#jj74 #ajib ,butterworth 7#jj74 #ajic ,farmer and ,hill 7#jb74 #ajid ,grand',eury 7#gg7 ,a4 p4 #ih4 #ajie ,stur 7#ge7 ,a4 ,pl4 ,,viii4 #ajif ,zeiller 7#jj7 p4 #ee4 #ajig ,kidston 7#hi71 ,pls4 ,i4 ,,ii4 ,for other figures of ,rhacopteris see also ,stur 7#ge7 ,a4 #ajih ,renault 7#if7 ,a4 p4 #cj1 ,pl4 ,,lxxxii4 figs4 #g-i4 #ajii ,stur 7#ge7 ,a4 #aajj ,weiss1 ,c4 ,e4 7#gi74 #aaja ,solms-,laubach 7#ia7 ,a4 p4 #ada4 #aajb ,o4 ,feistmantel 7#ge74 #aajc ,c4 ,feistmantel 7#gi74 #aajd ,c4 ,e4 ,weiss 7#gi74 #aaje ,potoni 7#ii7 p4 #afg4 #aajf ,seward 7#jc7 p4 #fc4 #aajg ,carruthers 7#gb7 ,pl4 ,,xxvii4 fig4 #e2 ,seward 7#jc7 p4 #fb4 #aajh ,newberry 7#ia7 ,pl4 ,,xiv4 #aaji ,d4 ,h4 ,scott 7#jh74 #aaaj ,p4 ,bertrand 7#ji74 #aaaa ,scott 7#ji74 #aaab ,williamson 7#hc7 ,a1 p4 #dgh4 #aaac ,lat4 communis1 common or general4 ,i am indebted to my friend ,mr ,l4 ,h4 ,g4 ,greenwood1 ,fellow of ,emmanuel ,college1 for supplying me with a name to express the idea of the generalized nature of these ,palaeozoic ferns4 #aaad ,arber 7#jf74 #aaae ,renault 7#if7 ,a4 p4 #df1 ,pls4 ,,xxx4 ,,xxxi4 ,see also ,tansley 7#jh7 fig4 #b1 p4 #ac4 #aaaf ,cotta 7#cb7 p4 #ae4 #aaag ,stenzel 7#hi7 ,pls4 ,i4 ,,ii4 #aaah ,stopes 7#jf74 #aaai ,williamson 7#hi7 ,a4 p4 #afb4 ,the term ,rachiopteris was adopted by ,williamson for petrified petioles from the ,coal-,measures which he believed to be filicinean4 #aabj ,renault 7#ge72 7#if7 ,a4 p4 #dg1 ,pl4 ,,xxxii4 #aaba ,oliver 7#jb74 #aabb ,oliver 7#jd7 p4 #cie 7footnote74 #aabc ,scott1 ,d4 ,h4 7#jh74 #aabd ,felix 7#hf7 ,a4 #aabe ,williamson 7#gh7 ,a4 p4 #cea4 #aabf ,hick 7#if74 #aabg ,scott 7#jh74 #aabh ,williamson 7#ia7 ,a4 p4 #bfa4 ,the two species described by ,williamson as ,rachiopteris hirsuta and ,r4 ramosa were first identified as ,botryopteris by ,scott in #ahih 7,british ,assoc4 ,report1 ,bristol ,meeting1 p4 #ajej74 #aabi ,tansley 7#jh7 p4 #ae4 #aacj ,kidston 7#jh74 #aaca ,oliver 7#jb74 #aacb ,corda 7#de7 ,a42 see also ,stenzel 7#hi7 p4 #bf4 #aacc ,p4 ,bertrand 7#ji7 pp4 #acf1 #bab4 #aacd ,tansley 7#jh7 p4 #bb4 #aace ,unger and ,richter 7#ef7 ,pl4 ,,vi4 fig4 #ai4 #aacf ,renault 7#if7 ,a4 p4 #aa4 #aacg ,the ,diplolabis type of strand is very similar in the form of the metaxylem to the conducting strand of a lateral vein in ,scolopendrium officinarum cf4 ,pelourde 7#ji7 fig4 #c1 p4 #aag4 #aach ,solms-,laubach 7#ib74 #aaci ,williamson 7#gd7 ,a4 ,pls4 ,,liv4 ,,lv4 #aadj ,gordon 7#ji74 ,mr ,gordon's more complete account of this plant will shortly be published4 ,i am indebted to him for furnishing me with the main facts in regard to the anatomical features4 #aada ,solms-,laubach 7#ib7 ,pl4 ,,ii4 fig4 #ac4 #aadb ,bertrand1 ,p4 7#ji7 p4 #baa4 #aadc ,pelourde 7#ji74 #aadd ,kidston and ,gwynne-,vaughan 7#jh7 p4 #bcj4 #aade ,ibid4 7#ji7 p4 #ffd4 #aadf ,a ,culm species ,rachiopteris aphyllus 7,unger7 is closely allied to ,metaclepsydropsis duplex4 ,see ,solms-,laubach 7#if7 p4 #cj4 #aadg ,unger and ,richter 7#ef7 p4 #afe4 #aadh ,corda 7#de7 ,a4 p4 #hc4 #aadi 1 water-clock4 #aaej ,p4 ,bertrand 7#ji7 p4 #abg4 #aaea ,stenzel 7#hi7 p4 #be4 #aaeb ,dr ,scott points out to me that recent observations1 which have not yet been published1 both by ,dr ,kidston and himself show that ,bertrand's terminology requires modification4 ,there are many points to be cleared up before we can hope to obtain a satisfactory classification of the ,zygoptereae4 #aaec ,stenzel 7#hi7 p4 #ca1 ,pls4 ,,vi4 ,,vii4 #aaed ,williamson 7#hi7 ,a4 p4 #aeh4 #aaee ,ibid42 see also ,scott 7#jh74 #aaef ,scott 7#jg7 p4 #ahj4 #aaeg ,renault 7#fi72 ,williamson 7#gd7 ,a4 p4 #fig4 #aaeh ,williamson 7#gg7 ,pls4 ,v4-,,vii4 #aaei ,williamson 7#hi7 ,a4 ,pl4 ,,viii4 fig4 #bh4 #aafj ,scott 7#jh7 p4 #cbb4 #aafa ,no4 #bde4 #aafb ,williamson 7#hj7 ,a4 p4 #ejg4 #aafc ,scott 7#jf74 #aafd ,solms-,laubach 7#if74 #aafe ,scott1 ,d4 ,h4 7#jf7 p4 #eai4 #aaff ,british ,museum1 section ,no4 #bde4 ,cf4 figures by ,williamson and ,bertrand3 ,williamson 7#gg7 ,pl4 ,v4 fig4 #ai2 ,bertrand1 ,p4 7#ji7 ,pl4 ,,xii4 fig4 #hg4 #aafg ,scott 7#jg7 p4 #ahb2 7#jh7 p4 #cah4 #aafh ,weiss1 ,f4 ,e4 7#jf74 #aafi ,williamson 7#gg74 #aagj ,williamson 7#hh7 ,a4 #aaga ,jordan 7#jc74 #aagb ,mc,nicol 7#jh74 #aagc ,gwynne-,vaughan 7#ji74 #aagd ,compare figures of the vascular cylinders of climbing ,dicotyledons given by ,schenck 7#ic74 #aage ,for a figure of the stele see ,tansley 7#jh7 p4 #be1 fig4 #bj4 #aagf ,stenzel 7#hi7 ,pls4 ,,iii4 and ,,iv4 #aagg ,binney 7#gb74 #aagh ,williamson 7#gd7 ,a4 #aagi ,bertrand1 ,p4 7#ji74 #aahj ,felix 7#hf7 ,a4 #aaha ,renault 7#fi74 #aahb ,grand',eury 7#gg7 ,a4 ,pl4 ,,xvii4 #aahc ,renault and ,zeiller 7#hh7 ,a4 #aahd ,white 7#ii7 p4 #ig4 #aahe ,binney 7#gb72 ,williamson 7#gd7 ,a4 p4 #fhe4 #aahf ,williamson 7#gd7 ,a4 p4 #fhe4 #aahg ,bertrand1 ,p4 7#ji7 ,pl4 ,,vii4 fig4 #dh4 #aahh ,scott 7#je7 p4 #aae4 #aahi ,bertrand1 ,p4 7#ji7 ,pl4 ,,vii4 #aaij ,scott 7#jd72 7#je74 #aaia ,scott 7#jf74 #aaib ,boodle 7#jh74 #aaic ,scott1 ,r4 7#jh7 ,pl4 ,,xxxiv4 figs4 #a1 #b4 #aaid ,baily 7#fj7 ,pl4 ,,xxi4 1 a club or mace4 #aaie ,zeiller 7#hc74 #aaif ,kidston 7#id74 #aaig ,potoni 7#jb7 p4 #dib4 #aaih ,zeiller 7#hh7 ,a4 ,pl4 ,x4 #aaii ,tansley 7#jh74 #abjj ,see p4 #ddg4 #abja ,stenzel 7#hi7 p4 #ae1 ,pls4 ,,iii4 ,,iv4 #abjb ,lindman 7#jd74 #abjc ,baker 7#hg7 ,a42 ,sadebeck1 in ,engler and ,prantl 7#jb74 #abjd ,campbell 7#jd72 ,bower 7#jh7 p4 #eea4 #abje ,schenk 7#ga7 p4 #bbe4 #abjf ,hollick 7#id7 ,pl4 ,,lxxi4 #abjg ,mentioned by ,krasser 7#jf7 in a preliminary note4 #abjh ,fri and ,bayer 7#ja7 p4 #hf1 fig4 #cd4 #abji ,heer 7#hb7 ,pl4 ,,xvi4 #abaj ,heer 7#ee7 ,a4 ,vol4 ,,iii4 p4 #aef1 ,pl4 ,,cxlv4 fig4 #ce4 #abaa ,goebel 7#je74 #abab ,see ,seward 7#id7 p4 #dda1 for a description of the floating plants on the lagunas of ,gran ,chaco 7,s4 ,america7 by ,prof4 ,graham ,kerr4 #abac ,bower 7#jh7 p4 #faa4 #abad ,hollick 7#id74 #abae ,e4g4 ,lesquereux 7#gh7 ,pl4 ,,lxiv4 fig4 #ad2 ,pl4 ,v4 fig4 #aj4 ,staub 7#hg7 ,pl4 ,,xix4 fig4 #b4 #abaf ,zeiller 7#jc7 ,pl4 ,,li4 figs4 #b1 #c4 #abag ,heer 7#ee7 ,a4 ,vol4 ,,iii4 p4 #aef1 ,pl4 ,,cxlv4 figs4 #a-cae4 #abah ,zeiller 7#ji7 p4 #ie4 #abai ,fritel 7#jh74 #abbj ,see also ,arber 7#jf7 p4 #bbh4 #abba ,solms-,laubach 7#ia7 ,a4 p4 #ahc4 #abbb ,dawson 7#hf74 #abbc ,zeiller 7#hh7 ,a4 p4 #eh4 #abbd ,corda 7#de7 ,a4 ,pl4 ,,liv4 #abbe ,presl1 in ,sternberg 7#ch7 ,a4 #abbf ,schimper 7#fi7 ,a4 #abbg ,nathorst 7#gh7 p4 #ag4 #abbh ,zigno 7#ef7 ,a4 ,pl4 ,,xx4 #abbi ,salfeld 7#ji7 p4 #ag4 #abcj ,in a footnote to ,fontaine's description of ,jurassic plants of ,oregon1 ,lester ,ward writes3--8,seward treats ,sagenopteris as a fern1 classing it now 7,jur4 ,fl4 ,yorkshire ,coast1 #aijj1 p4 #afa7 in the family ,polypodiaceae1 although in his ,wealden ,flora1 #ahid1 p4 #abi1 he placed it in the ,schizaeaceae40 ,ward 7#je7 p4 #hc1 note b4 ,my words are 8,i am disposed to regard ,sagenopteris as probably a genus of ferns0 7loc4 cit4 #aijj1 p4 #afa74 ,i have never referred this plant to the ,polypodiaceae or ,schizaeaceae or to any other family4 #abca ,solms-,laubach 7#ia7 ,a4 p4 #ahb4 #abcb ,i am indebted to my friend ,dr ,nathorst for calling my attention to ,lindman's paper4 #abcc ,for a fuller synonymy1 see ,seward 7#jj7 p4 #afb4 #abcd ,nathorst 7#jd74 #abce ,bunbury 7#ea7 ,a4 #abcf ,lindley and ,hutton 7#ce7 ,a4 ,pl4 ,,clv4 #abcg ,yabe 7#je7 ,pl4 ,,iii4 fig4 #af4 #abch ,moeller 7#jb7 ,pl4 ,,vi4 fig4 #aj4 #abci ,lindley and ,hutton 7#cc7 ,a4 ,pl4 ,,lxiii4 fig4 #b4 #abdj ,seward 7#jj7 p4 #afi1 fig4 #bf4 #abda ,zigno 7#ef7 ,a4 ,pl4 ,,xxi4 #abdb ,moeller 7#jb7 ,pl4 ,,vi4 figs4 #h1 #i4 #abdc ,ward 7#je7 ,pl4 ,,xv4 fig4 #e4 #abdd ,bartholin 7#ib7 ,pl4 ,v4 fig4 #i4 #abde ,presl1 in ,sternberg 7#ch74 #abdf ,zigno 7#ef7 ,a4 ,pls4 ,,xxi4 ,,xxii42 ,raciborski 7#id7 ,a4 ,pl4 ,,xx4 figs4 #ac-ah4 #abdg ,brongniart 7#be7 ,pl4 ,,xii4 fig4 #a4 #abdh ,fontaine1 in ,ward 7#je72 ,salfeld 7#ji7 ,pl4 ,i4 #abdi ,schenk 7#fg7 ,a4 ,pl4 ,,xiii4 #abej ,arber 7#je7 p4 #ge4 #abea ,seward 7#id7 ,a4 p4 #acj4 #abeb ,velenovsk 7#he7 ,pl4 ,,ii4 #abec ,fontaine1 in ,ward 7#je7 ,pl4 ,,lxv4 ,newberry's ,chiropteris spatulata from ,montana may be founded on leaflets of ,sagenopteris ,mantelli4 ,newberry 7#ia74 #abed ,brongniart 7#bh7 ,a4 p4 #fa4 #abee ,white 7#ic74 #abef ,white 7#ii7 p4 #adc4 #abeg ,schimper 7#fi7 ,a4 p4 #faj4 #abeh ,sellards 7#ja74 #abei ,weiss1 ,c4 ,e4 7#fi7 p4 #ih1 ,pl4 ,,vi4 fig4 #ac4 #abfj ,zeiller 7#id7 p4 #afi4 #abfa ,renault 7#if7 ,a4 p4 #a4 #abfb ,zeiller 7#ij7 ,pls4 ,,xii4 ,,xiii4 #abfc ,fontaine and ,white 7#hj7 ,pl4 ,,xxxiv4 #abfd ,fontaine and ,white 7#hj7 ,pl4 ,,xxxiv4 figs4 #a-h4 #abfe ,sellards 7#ja74 #abff ,grand',eury 7#gg7 ,a4 p4 #aga4 #abfg ,renault and ,zeiller 7#hh7 ,a4 #abfh ,potoni 7#ic7 ,a4 p4 #ade1 ,pl4 ,,xvii4 fig4 #c4 #abfi ,renault and ,zeiller 7#hh7 ,a4 p4 #bhb1 ,pl4 ,,xxii4 fig4 #aj4 #abgj ,feistmantel 7#ha7 ,a4 ,pls4 ,,xxi4 ,a4 ,,xxii4 ,a4 #abga ,oldham and ,morris 7#fc7 p4 #da4 #abgb ,schenk 7#fg7 ,a4 ,pl4 ,,xxviii4 fig4 #ab4 #abgc ,nathorst 7#gh7 ,pl4 ,,ix4 #abgd ,feistmantel 7#ij7 ,a4 ,pl4 ,,xxvii4 #abge ,saporta 7#gc7 ,a4 ,pls4 ,,lxi4 ,,lxii4 #abgf ,zeiller 7#jb7 ,pls4 ,x4-,,xiv4 p4 #ff4 #abgg ,zeiller 7#jb7 ,pl4 ,,xi4 fig4 #d4 #abgh ,zeiller 7#jb7 ,pl4 ,,xiii4 ,for synonymy1 see also ,arber 7#je7 p4 #abd4 #abgi ,seward 7#jd7 figs4 #ah-bb4 #abhj ,seward 7#jh7 p4 #ih4 #abha ,geinitz 7#gf7 ,pl4 ,,ii4 figs4 #a-c4 #abhb ,nathorst 7#gh7 ,pl4 ,,xix4 #abhc ,zeiller 7#jb7 ,pl4 ,,xiv4 #abhd ,for synonymy and distribution1 see ,seward 7#jj7 pp4 #aei1 #cjd4 #abhe ,schenk 7#fg7 ,a4 ,pl4 ,,xxv4 ,see also ,bartholin 7#ib7 ,pl4 ,,ix4 fig4 #g4 #abhf ,etheridge 7#id74 #abhg ,lindley and ,hutton 7#cc7 ,a4 ,pl4 ,,xcii4 #abhh ,seward 7#jj7 p4 #ad4 #abhi ,schenk 7#ga7 ,pl4 ,,xxix42 ,seward 7#id7 ,a4 p4 #abe4 #abij ,stiehler 7#eh7 ,pls4 ,,xii4 ,,xiii4 #abia ,see p4 #egf4 #abib ,nathorst 7#ij74 #abic ,for figures1 see ,stiehler loc4 cit4 and ,hosius and ,von der ,marck 7#hj7 ,pls4 ,,xliii4 ,,xliv4 #abid ,for synonymy1 see ,fontaine1 in ,ward 7#ii7 p4 #fea2 ,seward 7#id7 ,a4 p4 #aad2 ,seward 7#jj7 p4 #bj4 #abie ,brongniart 7#bb7 ,a4 ,pl4 ,,ii4 fig4 #d4 #abif ,brongniart 7#bh7 ,a4 ,pls4 ,,lxii4 ,,lxiii4 #abig ,schimper 7#fi7 ,a4 p4 #fde4 #abih ,seward 7#ig7 ,a4 p4 #cag4 #abii ,for figures see ,zeiller 7#if7 ,a42 ,zeiller 7#jb71 7#jc72 ,arber 7#je72 ,seward 7#ig7 ,a4 #acjj ,arber 7#je72 ,seward 7#jg74 #acja ,bunbury 7#fa7 ,pl4 ,,xi4 #acjb ,zeiller 7#if7 ,a4 #acjc ,oldham 7#ig72 ,zeiller 7#ig74 #acjd ,seward 7#ig7 ,a4 7#jg72 ,arber 7#jb7 p4 #bj2 ,zeiller 7#if7 ,a4 p4 #cgd4 #acje ,white 7#jh7 p4 #ece4 #acjf ,zeiller 7#jb74 #acjg ,potoni 7#jj74 #acjh ,seward 7#jd72 ,zeiller 7#ig72 ,arber 7#je7 p4 #ag2 ,d4 ,white 7#jg74 #acji ,amalitzky 7#ja72 ,zeiller 7#ih74 #acaj ,zeiller 7#jb74 #acaa ,d4 ,white 7#jg7 p4 #fag 7footnote #b74 #acab ,for synonymy1 see ,arber 7#je7 p4 #dh4 #acac ,zeiller 7#if7 ,a4 #acad ,mc,coy 7#dg74 #acae ,zeiller 7#if7 ,a4 #acaf ,arber 7#je72 7#je74 #acag ,seward 7#ig7 ,a2 7#jg74 #acah ,royle 7#cc74 #acai ,zeiller 7#if7 ,a4 #acbj ,zeiller 7#if7 ,a4 #acba ,oldham 7#ig74 #acbb ,zeiller 7#jb74 #acbc ,zeiller 7#jb7 ,pl4 ,v4 fig4 #g4 #acbd ,etheridge 7#id74 #acbe ,arber 7#je7 p4 #dg4 #acbf ,zeiller 7#if7 ,a4 p4 #cfh1 fig4 #ac4 #acbg ,zeiller 7#jb72 7#jc74 #acbh ,oldham 7#ig74 #acbi ,amalitzky 7#ja74 #accj ,zeiller 7#jc7 ,pl4 ,,xvi4 #acca ,zeiller 7#jb74 #accb ,seward and ,leslie 7#jh7 p4 #aac4 #accc ,dawson 7#ga7 ,a4 ,pl4 ,,xvii42 ,fontaine and ,white 7#hj7 p4 #aa2 ,white 7#ie7 p4 #cae2 ,arber 7#je7 p4 #cjg1 ,pl4 ,,xx4 #accd ,jack and ,etheridge 7#ib74 #acce ,lesquereux 7#gi7 ,a4 ,pl4 ,,xxv42 ,renault and ,zeiller 7#hh7 ,a4 ,pl4 ,,xxiii4 ,see p4 #eag4 #accf ,etheridge 7#ii74 #accg ,feistmantel 7#hj7 ,pls4 ,,xxviii4 ,a41 ,,xli4 ,a4 #acch ,seward 7#jg74 #acci ,mc,coy 7#dg74 #acdj ,arber 7#jb74 #acda ,mc,coy 7#fj7 p4 #ajg 7footnote74 #acdb ,mc,coy 7#ge74 #acdc ,feistmantel 7#gi74 #acdd ,seward and ,woodward 7#je7 p4 #b4 #acde ,arber 7#jb7 p4 #ad4 #acdf ,white1 ,d4 7#jg74 #acdg ,arber 7#je74 #acdh ,carruthers 7#fi7 p4 #i1 ,pl4 ,,vi4 fig4 #a4 #acdi ,seward 7#jc7 p4 #hc4 #acej ,hayden 7#jg72 ,seward 7#jg74 #acea ,darwin 7#hg7 ,a4 ,vol4 ,,iii4 p4 #bdh4 #aceb ,for synonymy1 see ,arber 7#je7 p4 #ajd4 #acec ,seward and ,smith ,woodward 7#je72 7#jg74 #aced ,white 7#jh7 pp4 #dgc1 #dhc4 #acee ,stur 7#hd7 p4 #fch4 #acef ,white 7#jh7 p4 #ecg1 ,pl4 ,,viii4 figs4 #h-aj4 #aceg ,ibid4 p4 #edc1 ,pl4 ,,ix4 figs4 #a-c4 #aceh ,feistmantel 7#hj7 ,pl4 ,,xxvii4 fig4 #e4 #acei ,lesquereux 7#hj7 ,a4 p4 #adb2 ,pl4 ,,xxv4 #acfj ,brongniart 7#bh7 ,a4 p4 #abi4 #acfa ,grand',eury 7#ij7 ,a4 ,pl4 ,,viii4 fig4 #e4 #acfb ,zeiller 7#ij7 p4 #aff1 ,pl4 ,,xiii4 fig4 #b4 #acfc ,renault and ,zeiller 7#hh7 ,a4 ,pl4 ,,xxiii4 fig4 #f4 #acfd ,lesquereux1 loc4 cit4 #acfe ,white 7#je7 p4 #cha4 #acff ,grand',eury 7#ij7 ,a4 p4 #cje4 #acfg ,schimper and ,mougeot 7#dd7 ,a4 #acfh ,schimper 7#fi7 ,a4 p4 #ddg4 #acfi ,carruthers 7#fi74 #acgj ,see ,arber 7#je7 p4 #aaf2 ,seward 7#jc7 p4 #he4 #acga ,white 7#jh7 p4 #dhc4 #acgb ,seward 7#jc7 p4 #hc4 #acgc ,zeiller 7#ie7 p4 #faf4 #acgd ,feistmantel 7#gi74 #acge ,kurtz 7#id74 #acgf ,schimper and ,mougeot 7#dd7 ,a4 ,pl4 ,,xxxviii4 #acgg ,blanckenhorn 7#he7 p4 #abg1 ,pls4 ,,xvii4-,,xix4 #acgh ,vol4 ,i4 p4 #bib4 #acgi ,zeiller 7#jj74 #achj ,blanckenhorn 7#he7 p4 #abi1 ,pl4 ,,xxi4 #acha ,blanckenhorn loc4 cit4 ,the specimens figured by this author are in the ,strassburg ,museum1 as are also some of those figured by ,schimper and ,mougeot4 #achb ,schimper 7#fi7 ,a4 p4 #deb4 #achc ,schimper and ,koechlin-,schlumberger 7#fb7 ,a4 #achd ,ibid4 #ache ,fritsch1 ,k4 7#ig74 #achf ,stur 7#ge7 ,a4 ,pl4 ,,xiv4 fig4 #a4 #achg ,grigoriew 7#ih7 ,pl4 ,,iv4 #achh ,schuster 7#jh7 p4 #ahd4 #achi ,presl1 in ,sternberg 7#ch7 ,a4 #acij ,for synonymy1 see ,zeiller 7#hh7 ,a4 p4 #cja4 #acia ,page #djf4 #acib ,potoni 7#jc7 p4 #afb4 #acic ,zeiller 7#jf7 ,pls4 ,,vi4 ,,vii4 #acid ,arber 7#jf74 #acie ,renault and ,zeiller 7#hh7 ,a42 ,zeiller 7#hh7 ,a4 ,pl4 ,,li4 #acif ,renault and ,zeiller 7#hh7 ,a4 ,pl4 ,,xxiv4 #acig ,grand',eury 7#ij7 ,a4 ,pl4 ,,xix4 #acih ,kidston 7#ia7 ,pl4 ,,xxxv4 #acii ,goebel 7#je7 p4 #cah4 #adjj ,see p4 #djf1 fig4 #bic2 ,potoni 7#jc7 also figures a young frond of ,dactylotheca plumosa partially covered by ,aphlebiae4 #adja ,seward 7#jj7 ,pl4 ,,xxi4 fig4 #a4 #adjb ,ibid4 p4 #ade4 #adjc ,raciborski 7#id7 ,a4 ,pl4 ,,xi4 #adjd ,brongniart 7#bb7 ,a4 #adje ,for synonymy1 see ,kidston 7#hf7 p4 #fh4 #adjf ,kidston 7#id7 p4 #bih4 #adjg ,zeiller 7#hh7 ,a4 p4 #adg1 ,pls4 ,,iv4 ,v42 ,kidston 7#hf7 p4 #hj4 #adjh ,see p4 #ece4 #adji ,lindley and ,hutton 7#ca7 ,a4 ,pl4 ,,xlv4 #adaj ,peach 7#gh74 #adaa ,kidston 7#hg7 p4 #ade4 #adab ,this species will be described in ,vol4 ,,iii4 #adac ,benson 7#jd74 #adad ,miller 7#eg71 ,frontispiece4 #adae ,scott 7#je7 p4 #add4 #adaf ,grand',eury 7#je74 #adag ,kidston 7#ja7 p4 #aia4 #adah ,potoni 7#ie72 7#ii74 #adai ,zeiller 7#gi74 #adbj ,kidston 7#ja7 p4 #aie4 #adba ,for synonymy1 see ,kidston 7#jc7 p4 #gga4 #adbb ,grand',eury 7#jh74 #adbc ,stur 7#ge7 ,a4 p4 #abj4 #adbd ,zeiller 7#gi72 7#hh7 ,a4 p4 #adb4 #adbe ,kidston 7#id7 p4 #bdj4 #adbf ,zeiller 7#hh7 ,a4 p4 #adg4 #adbg ,ibid4 ,pl4 ,,xvi4 #adbh ,potoni 7#ib74 #adbi ,nathorst 7#jb7 p4 #ae4 #adcj ,crpin 7#ge74 ,previously described by ,crpin 7#gd7 as ,psilophyton4 #adca ,gilkinet 7#ge74 #adcb ,nathorst 7#jb74 #adcc ,zeiller 7#ji7 p4 #bj4 #adcd ,ettingshausen 7#eb74 #adce ,sellards 7#jj74 #adcf ,for synonymy1 see ,seward 7#jc7 p4 #eb4 #adcg ,solms-,laubach and ,steinmann 7#ii7 ,pl4 ,,xiv4 fig4 #b2 ,szajnocha 7#hh74 #adch ,geinitz 7#gf7 ,pl4 ,i4 #adci ,seward 7#jh7 p4 #ie4 #addj ,feistmantel 7#ij7 ,a4 ,pl4 ,,xxiv4 #adda ,zeiller 7#jc74 #addb ,for references1 see ,seward 7#jd7 p4 #ca4 #addc ,berry 7#jc74 #addd ,seward 7#jd7 p4 #ca4 #adde ,hollick and ,jeffrey 7#ji7 p4 #bd4 #addf ,raciborski 7#id7 ,a4 ,pl4 ,,xx4 figs4 #a1 #b2 ,zeiller 7#jj7 p4 #ih4 #addg v4 #eiej4 #addh ,fontaine 7#hi7 ,pls4 ,,xvii4 ,,xviii4 #addi ,solms-,laubach 7#ia7 ,a4 p4 #ada4 #adej ,schimper 7#fi7 ,a4 p4 #dgb4 #adea ,kurr 7#de7 ,pl4 ,,ii4 fig4 #a4 #adeb ,seward 7#jd7 p4 #cj4 #adec ,saporta 7#gc7 ,a4 #aded ,schenk 7#fg7 ,a4 #adee ,salfeld 7#jg7 p4 #aib4 #adef ,seward 7#jd7 p4 #cd1 fig4 #b1 ,pl4 ,,iv4 #adeg ,salfeld 7#ji74 #adeh ,schenk 7#gf7 ,pl4 ,,xxvi4 fig4 #g4 #adei ,salfeld 7#ji7 p4 #cd4 #adfj ,zigno 7#ef7 ,a4 #adfa ,solms-,laubach 7#ia7 ,a4 p4 #aad4 #adfb ,nathorst 7#gh74 #adfc ,saporta 7#gc7 ,a4 p4 #ceb4 #adfd ,nathorst 7#gh7 p4 #abb4 #adfe ,zeiller 7#jc7 p4 #eb4 #adff ,leckenby 7#fd7 ,a4 ,pl4 ,x4 fig4 #a2 ,seward 7#jd7 p4 #cf4 #adfg ,schenk 7#hg74 #adfh ,zeiller 7#jc7 ,pls4 ,,vi4-,,viii4 #adfi ,zigno 7#ef7 ,a4 ,pls4 ,,xii4 ,,xiii4 #adgj ,seward 7#jj7 p4 #agj4 #adga ,brongniart 7#bh7 ,a4 p4 #di4 #adgb ,seward 7#jj7 p4 #aga4 #adgc ,saporta 7#gc7 ,a4 p4 #cfh4 #adgd ,krasser 7#ie74 #adge ,saporta 7#gc7 ,a4 ,pl4 ,,xlvii4 #adgf ,brongniart 7#bh7 ,a4 p4 #fj4 #adgg ,kidston 7#ja7 p4 #aif4 #adgh ,potoni 7#ic7 ,a4 ,pl4 ,,xv4 #adgi ,kidston 7#hi7 p4 #dji4 #adhj ,zeiller 7#jf7 ,pls4 ,,xix4-,,xxii42 7#jj7 p4 #ajj1 fig4 #gc4 #adha ,weiss1 ,c4 ,e4 7#gj74 #adhb ,zeiller 7#jf7 p4 #ij4 #adhc ,lesquereux 7#hj7 ,a4 p4 #aca2 ,weiss 7#gj74 #adhd ,weiss 7#fi7 p4 #cg4 #adhe ,grand',eury 7#gg7 ,a4 ,pl4 ,a4 #adhf ,renault and ,zeiller 7#hh7 ,a4 p4 #bai4 #adhg ,stur 7#hd74 #adhh ,grand',eury 7#gg7 ,a4 ,pl4 ,,xiii4 #adhi ,grand',eury 7#jh74 #adij ,renault and ,zeiller 7#hh7 ,a4 ,pl4 ,,xxiv4 #adia ,weiss1 ,c4 ,e4 7#fi72 ,goeppert 7#fd7 ,a42 ,potoni 7#ic7 ,a1 7#jd72 ,lesquereux 7#hj7 ,a41 p4 #abd2 ,white 7#ii7 p4 #abe4 #adib ,seward 7#jh7 p4 #ig1 ,pl4 ,,viii4 #adic ,brongniart1 in ,murchison1 ,verneuil1 and ,keyserling 7#de7 ,pl4 ,a4 #adid ,weiss1 ,c4 ,e4 7#gj7 p4 #hga4 #adie ,brongniart 7#di7 ,a4 p4 #bd4 #adif ,grand',eury 7#jf74 #adig ,weiss 7#fi7 ,pls4 ,,vi4 ,,vii4 #adih ,potoni 7#ic7 ,a4 ,pl4 ,i4 figs4 #a1 #b4 #adii ,weber and ,sterzel 7#if7 p4 #ii4 #aejj ,zeiller 7#ij7 p4 #hd4 #aeja ,zeiller 7#ih74 #aejb ,for figures of this and other species1 see ,potoni 7#jg74 #aejc ,for synonymy1 see ,zeiller 7#ij7 p4 #hg and ,potoni 7#jg7 p4 #b4 #aejd ,schuster 7#jh7 ,pl4 ,,viii4 fig4 #g4 #aeje ,weiss1 ,c4 ,e4 7#gj74 #aejf ,schlotheim 7#bj7 ,a4 p4 #djf4 #aejg ,renault and ,zeiller 7#hh7 ,a4 ,pl4 ,,xix4 #aejh ,white 7#je7 p4 #chh4 #aeji ,forbes 7#ec7 p4 #dc4 #aeaj ,baily 7#ei7 p4 #ge4 #aeaa ,schimper 7#fi7 ,a4 p4 #dgc4 #aeab ,dawson 7#ga7 ,a4 p4 #dh2 7#hb74 #aeac ,kidston 7#ia7 p4 #cj1 ,pl4 ,,iii42 7#jf7 p4 #dcd4 #aead ,baily 7#ge7 ,pl4 ,,xxviii4 #aeae ,carruthers 7#gb7 ,pl4 ,,ii4 #aeaf ,dawson 7#ga7 ,a4 #aeag ,smith and ,white 7#je7 p4 #ci4 #aeah ,lesquereux 7#hj7 ,a4 #aeai ,crpin 7#gd74 #aebj ,nathorst 7#jb74 #aeba ,schmalhausen 7#id74 #aebb ,nathorst 7#jd74 #aebc ,krasser 7#jj7 ,pl4 ,i4 figs4 #c-g4 #aebd ,zeiller 7#jc7 p4 #bg4 #aebe ,stur 7#ge7 ,a4 ,pls4 ,,viii4 ,,xii4 ,,xvi4 #aebf ,kidston 7#hh74 #aebg ,grand',eury 7#jh74 #aebh ,brongniart 7#bb7 ,a4 #aebi ,kidston 7#je74 #aecj ,renault 7#gf74 #aeca ,grand',eury 7#jh74 #aecb ,white 7#ii7 p4 #abh4 #aecc ,grand',eury 7#gg7 ,a4 p4 #abb4 #aecd ,zeiller 7#ij7 ,pl4 ,,xi4 fig4 #f4 #aece ,potoni 7#ii7 p4 #aac4 #aecf ,renault 7#hb7 ,a4 ,vol4 ,,iii42 ,zeiller 7#ij7 p4 #aci4 #aecg ,grand',eury 7#gg7 ,a4 p4 #aje4 #aech ,brongniart 7#bb7 ,a4 ,pl4 ,,ii4 fig4 #f4 ,for synonymy1 see ,kidston 7#jc7 p4 #ggc2 ,zeiller 7#hh7 ,a4 p4 #bfa4 #aeci ,for synonymy1 see ,kidston 7#hh7 p4 #ced4 #aedj ,scheuchzer 7#agbc7 ,a4 p4 #abi1 ,pl4 ,x4 fig4 #c4 #aeda ,lhywd 7#agfj7 ,a4 ,pl4 ,v4 fig4 #aij4 #aedb ,lesquereux 7#gi7 ,a4 ,pl4 ,,viii4 #aedc ,fontaine and ,white 7#hj7 p4 #dg4 #aedd ,bunbury 7#dg7 ,pl4 ,,xxi4 #aede ,kidston 7#id7 p4 #ceg2 7#jc7 p4 #hjf4 #aedf ,white 7#ii7 p4 #acb4 #aedg ,zeiller 7#hh7 ,a4 p4 #bea4 #aedh ,see ,vol4 ,i4 p4 #de4 #aedi ,zalessky 7#jg7 ,pl4 ,,xxiv4 fig4 #e4 #aeej ,zeiller 7#hh7 ,a4 p4 #bea4 #aeea ,renault and ,zeiller 7#hh7 ,a4 p4 #bea1 ,pl4 ,,xxxii4 #aeeb ,brongniart 7#bh7 ,a4 p4 #ea4 #aeec ,lindley and ,hutton 7#cc7 ,a4 p4 #bh4 #aeed ,lesquereux 7#ff7 ,a4 #aeee ,roehl 7#fi74 #aeef ,seward 7#hh74 #aeeg ,potoni 7#ii7 p4 #aec 7note74 #aeeh ,gutbier 7#ce74 #aeei ,presl1 in ,sternberg 7#ch7 ,a4 #aefj ,grand',eury 7#jd74 #aefa ,zeiller 7#ij7 ,pl4 ,,xi4 fig4 #i4 #aefb ,zeiller 7#ii7 p4 #df4 #aefc ,bunbury 7#dg7 ,a4 p4 #dbg4 #aefd ,lyell 7#de7 ,a4 ,vol4 ,,ii4 p4 #bjb4 #aefe ,lesquereux 7#hj7 ,a4 p4 #adf4 #aeff ,sternberg 7#bf7 ,a4 #aefg ,grand',eury 7#jd74 #aefh ,grand',eury 7#ij7 ,a4 #aefi ,zeiller 7#ij7 ,pl4 ,,ix4 fig4 #f1 ,a4 #aegj ,stur 7#hc74 #aega ,scott 7#jg7 p4 #bjf2 ,scott and ,maslen 7#jf7 p4 #aab4 #aegb ,grand',eury 7#jd74 #aegc ,for synonymy1 see ,kidston 7#jc7 p4 #ggb3 ,zeiller 7#hh7 ,a4 #aegd ,scheuchzer 7#agbc7 ,a4 ,pl4 ,i4 fig4 #d4 #aege ,kidston 7#id7 p4 #bde4 #aegf ,for synonymy1 see ,kidston 7#id7 p4 #eif2 7#jc7 p4 #hjf2 ,white 7#ii7 p4 #aag4 #aegg ,grand',eury 7#jd74 #aegh ,kidston 7#id7 p4 #bde4 #aegi ,brongniart 7#bh7 ,a4 p4 #ei4 #aehj ,page #did4 #aeha ,kidston 7#id7 p4 #eif4 #aehb ,grand',eury 7#je74 #aehc ,potoni 7#ib72 7#ic7 p4 #ed4 #aehd ,for synonymy1 see ,kidston 7#hh7 p4 #cff4 #aehe ,zeiller 7#ij7 p4 #de2 ,potoni 7#ic7 ,a4 p4 #eg4 #aehf ,germar 7#dd7 ,pls4 ,,xxxv4 ,,xxxvi4 #aehg ,kidston 7#hh7 p4 #cff4 #aehh ,stur 7#hc74 #aehi ,renault and ,zeiller 7#hh7 ,a4 p4 #aif4 #aeij ,potoni 7#ic7 ,a4 p4 #dh4 #aeia ,zeiller 7#jj7 p4 #hh4 #aeib ,page #cig4 #aeic ,renault and ,zeiller 7#hh7 ,a4 p4 #agh1 ,pls4 ,v4-,,viii4 ,ante1 p4 #dai4 #aeid ,potoni 7#jb74 #aeie ,schimper 7#fi7 ,a4 p4 #fhh4 ---------------------------------------- ------------------------------ ,,cambridge3 ,,printed ,,by ,,john ,,clay1 ,m4,a4 ,,at ,,the ,,university ,,press4 ,,cambridge ,,biological ,,series ,general ,editor1 ,a4 ,e4 ,,shipley1 ,m4,a41 ,f4,r4,s41 ,master of ,christ's ,college4 ,a ,text-,book of ,zoogeography4 ,by ,,frank ,e4 ,,beddard1 ,m4 ,a41 ,f4,r4,s41 ,prosector of the ,zoological ,society of ,london4 ,crown #hvo4 ,with #e maps4 #fs4 ,the ,elements of ,botany4 ,by ,,francis ,,darwin1 ,sc4,d41 ,m4,b41 ,f4,r4,s41 ,fellow of ,christ's ,college4 ,second edition4 ,crown #hvo4 ,with #id illustrations4 #ds4 #f;d4 ,journal of ,education4 ,a noteworthy addition to our botanical literature4 ,practical ,physiology of ,plants4 ,by ,,francis ,,darwin1 ,sc4,d41 ,f4,r4,s41 and ,e4 ,,hamilton ,,acton1 ,m4,a4 ,crown #hvo4 ,with #de illustrations4 ,third edition4 #ds4 #f;d4 ,nature4 ,the authors are much to be congratulated on their work1 which fills a serious gap in the botanical literature of this country4 ,morphology and ,anthropology4 ,by ,w4 ,l4 ,h4 ,,duckworth1 ,m4,a41 ,m4,d41 ,fellow and ,lecturer of ,jesus ,college1 ,university ,lecturer in ,physical ,anthropology4 ,demy #hvo4 ,with #ccc illustrations4 #aes4 net4 ,athenum4 ,mr ,duckworth has managed to produce in his 8,morphology and ,anthropology0 just such a text-book as students have long been asking for4444 ,it is no easy task to have undertaken such a work and the author is to be congratulated on the success which has attended his efforts4 ,the volume can be confidently recommended to all whose studies lead them in this direction4 ,lectures on the ,history of ,physiology during the ,sixteenth1 ,seventeenth and ,eighteenth ,centuries4 ,by ,sir ,m4 ,,foster1 ,k4,c4,b41 ,m4,d41 ,d4,c4,l4 ,demy #hvo4 ,with a frontispiece4 #is4 ,nature4 ,there is no more fascinating chapter in the history of science than that which deals with physiology1 but a concise and at the same time compendious account of the early history of the subject has never before been presented to the ,english reader4 ,physiologists therefore owe a debt of gratitude to ,sir ,michael ,foster for supplying a want which was widely felt4444 ,no higher praise can be given to the book than to say that it is worthy of the reputation of its author4 ,the ,soluble ,ferments and ,fermentation4 ,by ,j4 ,,reynolds ,,green1 ,sc4,d41 ,f4,r4,s41 ,professor of ,botany to the ,pharmaceutical ,society of ,great ,britain4 ,second edition4 ,demy #hvo4 #abs4 ,nature4 ,it is not necessary to recommend the perusal of the book to all interested in the subject since it is indispensable to them1 and we will merely conclude by congratulating the ,cambridge ,university ,press on having added to their admirable series of ,natural ,science ,manuals an eminently successful work on so important and difficult a theme1 and the author on having written a treatise cleverly conceived1 industriously and ably worked out1 and on the whole1 well written4 ,a ,treatise on the ,british ,freshwater ,alg4 ,by ,g4 ,s4 ,,west1 ,m4,a41 ,a4,r4,c4,s41 ,f4,l4,s41 ,lecturer in ,botany in the ,university of ,birmingham4 ,demy #hvo4 ,with a frontispiece and #aff illustrations4 #ajs4 #f;d4 net4 ,nature4 ,its aim is stated as 8to give the student a concise account of the structure1 habits and life-histories of ,freshwater ,alg1 and also to enable him to place within the prescribed limits of a genus any ,alg he may find in the freshwater of the ,british ,islands40 ,to do this within the limits of an octavo volume of less than #djj pages1 in which are numerous illustrations1 is a task possible of accomplishment only by one very familiar with the subject and skilled in concise expression2 but that it has been successfully done will1 we think1 be the verdict after testing the book thoroughly4444 ,prof4 ,west's treatment of his subject is instructive and stimulating4 ,a ,manual and ,dictionary of the ,flowering ,plants and ,ferns4 ,by ,j4 ,c4 ,,willis1 ,m4,a41 ,sc4,d41 ,director of the ,royal ,botanic ,gardens1 ,ceylon4 ,third edition4 ,crown #hvo4 #ajs4 #f;d4 ,field4 ,taking this handy volume and a local flora1 the traveller or student may do an enormous amount of practical field work without any other botanical literature whatever4444 ,the result is a work that ought to be included in every library of botany and horticulture or agriculture1 and it is certainly one that the nomadic botanist cannot afford to leave at home4444 ,we have used the original edition of this work since its publication1 and have found it to be one of the most useful and comprehensive works on plants ever produced4 ,athenum4 ,the whole is well abreast of modern research1 and a thoroughly business-like volume1 lucid though compact4 ,agriculture in the ,tropics4 ,an elementary ,treatise4 ,by ,j4 ,c4 ,,willis1 ,m4,a41 ,sc4,d4 ,demy #hvo4 ,with #be plates4 #gs4 #f;d4 net4 ,palontology--,invertebrate4 ,by ,,henry ,,woods1 ,m4,a41 ,f4,g4,s41 ,university ,lecturer in ,palozoology4 ,crown #hvo4 ,fourth edition4 ,with #aea illustrations4 #fs4 ,outlines of ,vertebrate ,palontology for students of ,zoology4 ,by ,,arthur ,,smith ,,woodward1 ,m4,a41 ,f4,r4,s41 ,keeper of the ,department of ,geology in the ,british ,museum4 ,demy #hvo4 ,with #bbh illustrations4 #ads4 ,athenum4 ,the author is to be congratulated on having produced a work of exceptional value1 dealing with a difficult subject in a thoroughly sound manner4 ,,cambridge ,,university ,,press ,london3 ,,fetter ,,lane1 ,e4,c4 ,c4 ,f4 ,,clay1 ,,manager ,edinburgh3 #ajj1 ,,princes ,,street ,,also ,london3 ,h4 ,k4 ,,lewis1 #acf1 ,,gower ,,street1 ,w4,c4 ,transcriber's ,notes3 - ,text enclosed by underscores is in italics 7italics74 - ,text enclosed by equals is in bold 7bold74 - ,text enclosed by tildes is in antiqua 7antiqua74 - ,blank pages have been removed4 - ,obvious typographical errors have been silently corrected4 - ,odd-numbered page headings are entered at approximate locations as sidenotes1 except where repeated1 or duplicated in headings4 - ,some headings and table of contents have been modified to be more consistent4