﻿236 RELATIONSHIPS. 



SYSTEMATIC POSITION OF THE CYCADEOIDFJE. 



A most striking fact has become evident from the discoveries announced in 

 the foregoing chapters and brought together in a comparative survey of the vege- 

 tative and reproductive features of the two great eycadean lines. The hiatus 

 between these is of a two-fold character due to an ancient reproductive advance on 

 the one hand and a later vegetative advance on the other. In the existing cycads 

 complication of the cortical bundle system has arisen, while the reproductive organs 

 are relatively little changed and primitive. Conversely, in the Cycadeoidese, with 

 the retention of a more primitive cortical system, there were in part most surprising 

 reproductive changes leading up to the bisexual flower which mimics that of the 

 angiosperms. 



The question next to be answered is whether two groups so related shall be 

 included in one and the same greater gymuosperm class, the Cycadales, or whether 

 the Cycadeoidese shall be excluded from the true Cycadales, as the Bennettitales or 

 Cycadeoidales. Both these classifications have been held to best express the facts ; and 

 it must certainly be a source of profound satisfaction to botanists that what have been 

 regarded as two great groups of gymnosperms have been brought by investigation 

 and fortunate discoveries into the near juxtaposition indicated by such difference of 

 opinion. 



The idea that the Cycadeoidese represent a separate great group or gymuosperm 

 class, the Bennettitales, has been given force of authority by adoption in Engler und 

 Prantl. This is also the view of Solms-Laubach and Lignier. On the other hand, 

 Scott says in his studies in Fossil Botany, page 474 : 



"It appears, then, that there are at present known to us three distinct families of 

 Cycadales — on the one hand, the Zamias and the Cycadeae, still existing, and together 

 constituting the order Cycadacese; and, on the other, the Bennettiteae, wholly extinct, 

 and so different from the other two as to merit ordinal rank." 



This is likewise the opinion that has been sustained by Zeiller and Wieland. 

 In reviewing various contributions of the latter, Zeiller (217) thus states with pre- 

 cision the views that can only be regarded as fully borne out and confirmed by the 

 more extended studies recorded in the present volume: 



"* * * On a affaire la, en somme, a. de veritable fleurs, a appareil femelle central 

 entoure, pourrait-on dire, d'un cercle d'etamines composees, fleurs morphologique- 

 ment hermaphrodites, et constitutes, ainsi que le fait remarquer l'auteur, sur le 

 plan qui caracterise les fleurs des Angiospermes. M. Wieland insiste, d'une part, sur 

 les aflinites que tend a d6noter, entre les Bennettitees et les Marattiacees, ce groupe- 

 ment des sacs polliniques en synangium si semblables a ceux des Marattia, d'autre 

 part, sur les analogies qui existent entre ces androphylles de Bennettitees et les 

 carpophylles des Cycas; il presume que les Cycadinees ont du descendre de quelque 

 type ancestral tel qu'une Cycadofilicinfie heterosporee, a microsporanges et a. macro- 

 sporanges localises sur des frondes distinctes construites sur le meme plan que les 

 froudes steriles, et de laquelle on est passe, des Cryptogames, a des Gymnospermes 

 a appareil male seniblable a celuides Bennettitees, a appareil femelle semblable a celui 

 des Cycas. L'association identique que realiseut en sens inverses les Cycas et les Ben- 

 nettitees, d'appareils en forme de cone pour l'un des sexes avec des appareils en forme 



