354 Causes and Course of Organic Evolution 



ferns of lowly organization, all of wliich except Ceratopteris 

 are now extinct. 



Somewhat distantly related to the last is the carboniferous 

 group of the Botryopteridese, which in its simple monostelic 

 stem, its spirally placed leaves — that like Ceratopteris were 

 at least dimoiphic — , in the reduction of the sporophyll lamina, 

 in the often spherical sporangia with extensive annulus and 

 short broad stalk suggests affinity to the Parkeriacese. But 

 the Botryopteridese again have been regarded by most recent 

 observers as showing marked affinities mth the Osmundacese, 

 or the royal and cinnamon fern types. The origin of other 

 subdivisions of the Filicinese it would be inadvisable to trace 

 here in any detail. 



The term Archseocycadeae we use to designate that assem- 

 blage of palaeozoic plants which — as set forth in the table — 

 gradually gave origin to distinct families like the Pecopteridese, 

 the Lyginodendreae, the Medullosese, and Bennetitese, that 

 are now wholly extinct, as well as to the Cycadese, that are 

 represented by living genera. As set forth in the diagram, 

 these all probably had an ancient common origin with the 

 Archseofilicinese, and especially ^^dtll Protomarattiacese. 



So much is this the case that many lower carboniferous 

 plant organisms, whose leafy impressions the writer has often 

 laid bare in countless number, appear exactly fern-like in aspect 

 and veining. But studies made of the stem, the branches, 

 and the reproductive organs, as well as the leaves, during the 

 past quarter century, have clearly demonstrated that these 

 belonged to plants wliich had evolved, even during the lower 

 carboniferous period, to the stage of being seed-bearing plants 

 or spermatophytes. 



The mode of growth of their stem showed a striking parall- 

 elism to that of pinaceous and even dicotyledonous stems, 

 as well as to that already noted for the group Lepidodendreie. 

 But we would regard it purely as a case of moi-phological par- 

 allelism. On the other hand much can be said in favor of 

 our viewing the four extinct groups and the single persisting 

 group as ha\ang all been derived from one or a few common 

 and very ancient ancestors, of at least lower devonian if not 

 silurian age. 



The Lyginodendrese, Aneimitese, Pecopteridese, and Medul- 

 loseae attained their growth climax and greatest wealth of 

 indi\T[duals, during lower to upper carboniferous times, but 

 they in turn had largely or wholly died out when the Bennet- 

 iteae were attaining to their developmental climax in the juras- 



