CORDAITEAE 539 



of erect ; these differences, however, are of trifling im- 

 portance. The male catkin of Cordaianthus would thus 

 chiefly differ from that of Ginkgo, in the presence of 

 sterile bracts among the sporophylls, a difference com- 

 parable to the relation which we find, in a remote family, 

 between the strobilus of a Calamostachys and that of a 

 recent Equisetum. The data, however, are insufficient 

 to justify any definite conclusion as to the exact 

 morphology of the male Cordaianthus. It is quite clear, 

 at any rate, that its structure is totally distinct from 

 that of the male cone of a Cycad, and very different 

 from that of a Conifer, or from the male inflorescence 

 of Gnetaceae. On the whole, Ginkgo affords perhaps 

 the best parallel. 



The pollen-grains of Cordaianthus were rather large, 

 measuring, in some examples studied by M. Renault, 

 .09 x .05 mm., their form thus being ellipsoidal. The 

 outer membrane had a rather rough surface ; in the 

 interior of the pollen-grain, a small group of cells 

 (prothallus or antheridium) can often be detected (Fig. 

 195, C), an important observation, to which we shall 

 return, when speaking of the phenomena of pollination. 



B. The Female Flower 



M. Renault found that the young female catkins of 

 Cordaites were scarcely to be distinguished from the 

 male by external characters, though somewhat more 

 globular in form. In the early stages, the ovules were 

 completely hidden by the overlapping bracts. Here 

 also, sections of the silicified specimens have revealed 

 the internal organisation. In a fructification, to which 



