No. 544] BOTANICAL SOCIETY OF AMERICA 221 



that paleobotany will presently be able to uncover all of 

 the essential morphology of the great fossil groups. 



This picture of paleozoic ferns is somewhat dim yet, 

 but were it not for the recent work in paleobotany we 

 should have no picture at all, or, what is worse, an 

 entirely false one. 



The most conspicuous contribution of modern paleo- 

 botany, however, is its remarkably complete reconstruc- 

 tion of the phylogeny of gymnosperms. Our present 

 records of this group extend through a longer period and 

 are more continuous than for any other vascular group. 

 It was not only associated with the paleozoic pterido- 

 phytes of the Coal-measures, but it was contemporaneous 

 with pteridophytes throughout all their recorded history. 

 Seed-plants, therefore, are just as old as any vascular 

 plants, so far as our records go. It is clear that seed- 

 plants have descended from pteridophytes, but when our 

 records begin, they had already descended. 



Our conception of gymnosperms before the paleobo- 

 tanical work of the last decade, will emphasize the change 

 that has taken place. We thought of them as cycads, 

 conifers, and gnetums ; and the morphology of that time 

 undertook to develop a phylogenetic sequence with these 

 three groups. Cycads were clearly the most primitive 

 gymnosperms, and when Ginkgo was found to share with 

 them in the retention of swimming sperms, it was just as 

 clearly a " transition" form, on its way from cycads to 

 conifers. In the dim paleozoic background Cordaitales 

 lurked, but they were quite detached from living gymno- 

 sperms, a group that belonged to the gelogist rather than 

 to the botanist. I fancy that many a student of gymno- 

 sperms in those distant days never even heard of Cor- 

 daitales. The contrast between such a perspective of the 

 group as I have just indicated and the perspective we 

 possess to-day is due almost entirely to paleobotany. 



In the first place, it resurrected the most primitive 

 group of gymnosperms, the Cycadofilicales, called by our 

 English brethren the Pteridosperms. It is a group that 



