G. R. Wieland — Cycadeoidean Flower-hud Structure. 135 



ten years. The latest contribution on the Paleozoic Cycado- 

 filicaleans is a most interesting paper by Bertrand, which has 

 just now come to hand. This paper deals with jYeuropteris. 

 New facts are brought out in regard to peculiar orbicular 

 leaves bearing the pollen, and seeds of what I call the leafy- 

 type are figured. But I regret to find that once more a Euro- 

 pean student fails to draw comparisons with the Codonotheca 

 (Sellards, 1903). Sellards' original paper gives a good descrip- 

 tion of the outer form of the fruit, shows the probable bundle 

 pattern of the sporophylls, and suggests pointedly the probable 

 Xeuropterid affinity. As in the case of the jYeuropteris seeds 

 so far described the finer structure of the sporophylls is not 

 determined, but the very large microspores are remarkably con- 

 served. I have before suggested the need to reconcile this 

 form with other and later described JYeuropteris seeds, so 

 called. Taken in conjunction with the forms reconstructed 

 by Bertrand, Codonotheca shows that the fruits of the Paleo- 

 zoic " quasi-ferns " must have exhibited an extraordinary range 

 of structure, and it would appear that some of the fossils con- 

 sidered to be jYeuropteris seeds are in reality bisporangiate 

 buds. At least, it is to be observed that the internal structure 

 of the JVeuropteris seeds of large leafy form is little understood ; 

 although these remarks do not, of course, apply to distinctly 

 small and winged seeds like those of Pecopteris Pluckeneti. 



In closing the presentation of this hypothesis for the origin 

 of the seed canopy and lagenostome, I may add that I do not 

 see that there is any really fundamental divergence from earlier 

 views, especially because hypotheses based on a relative absence 

 of evidence usually contain their own sufficient negation. 

 Thus a seed must be much more than merely a " megasynan- 

 gium." Moreover, these newer views of seed coat origin go 

 far to explain the large size of the seeds and the relatively 

 small number of flowers in cycadaceous plants ; while the ovu- 

 late crown of Cycas in turn assumes a certain complexity of 

 structure more in accord with other cycad strobili, and also 

 with the Gnetalean strobili. Evidently Cycas only appears 

 ancient and primitive because it still retains in full the old 

 impulse to fruit from a leafy crown. 



For, in a way, it would seem that Cycas, though so ancient 

 of aspect, is also the most specialized cycad, with ovules aris- 

 ing from adventitious bud meristems of the axis of the so- 

 called carpellary leaf, w T hich is thus complex rather than 

 primitive. To coin a term, Cycas may be a compoundly 

 branched and platystrobiline form in which the fertile ovulate 

 crown corresponds in a larger sense to a crown of strobili of 

 the usual cylindrical type. However, not to go into a long 

 diversion, at best only speculative, I content myself with say- 



