﻿FOSSIL PLANTS OF THE GROUP CYCADOFILICES 

 By DAVID WHITE 



Introduction 



The group of fossil plants appropriately designated the " Cycado- 

 filices " embraces a number of Paleozoic generic types combining 

 structural characters of the ferns and of the gymnosperms. As 

 originally established by Potonie 1 it was confined chiefly to genera 

 founded on petrified trunks, petioles, and roots, with the provisional 

 reference of several frond types. Subsequent research has estab- 

 lished the correlation of the fronds of several of the members, and 

 recently two distinct types of seeds have been definitely identified 

 with two of the Cycadofilic genera, while a third type of fruit has 

 been found united with a genus of fronds not before suspected of 

 belonging to the Cycadofilices. The fact of the discovery of the 

 seeds has been brought to the attention of biologists in this country 

 by several American paleobotanical writers 2 whose brief communi- 

 cations on the subject are confined largely to the nomenclatorial 

 classification of the group, rather than to the characters of the latter. 

 So far-reaching are the paleobotanical findings concerning the mem- 

 bers of this group, and so important are they to all evolutionists, 

 that it seems desirable to put American botanists in closer touch 

 with the principal and very interesting features relating to these 

 singular types which appear to stand intermediate to the ferns and 

 the gvmnosperms. To do this in brief form is the purpose of this 

 paper. 



The number of genera to be included in the Cycadofilices. or 

 Pteridospermese, as designated by Oliver and Scott, is necessarily 

 indefinite, since future discovery will doubtless bring to light char- 

 acters causing the inclusion therein of other genera whose structure 

 or fructification is at present unknown and whose systematic classi- 

 fication is therefore now provisional only. On the other hand, a 

 more complete knowledge of the reproduction in some of the types 

 now included may require their promotion to a higher, gymno- 

 spermic, rank. It must be remembered that some of the genera are 



1 Lchrbuch der Pflanzenpaleontologie, 1899, p. 160. 



- Lester F. Ward in Science, July 1, 1904, P- 25; Aug. 26, p. 279. E. W. 

 Berry in Science, July 8, 1904, P- 56; July 15, P- 86; J. M. Coulter in Science, 

 July 29, 1904, p. 140. 



