THE VASCULAR CRYPTOGAMS 31 



of the embryo are connected with the presence of the 

 absorbing organ called the foot, which in Selaginella and 

 most of the higher Cryptogams performs a function 

 (that of absorbing food from the prothallus) which in 

 most Flowering Plants is discharged by the cotyledon or 

 cotyledons. 



Comparison between Selaginella and the Gymnosperms 



At first sight the differences between even the highest 

 Flowerless Plants, such as Selaginella, and the Flowering 

 Plants, seem so great that we see little in common 

 between them. In the Cryptogams we find no obvious 

 flowers and no seeds, while fertilisation takes place in a 

 totally different way from that with which we have 

 become familiar in Phanerogams. If, however, we 

 carefully compare the development of Selaginella with 

 that of a gymnospermous Flowering Plant, we shall find 

 it quite possible to trace the corresponding stages in 

 their life-history ; and, having accomplished this for the 

 lower Flowering Plants and the higher Cryptogams, it 

 will not be impossible to extend the comparison further so 

 as to include the Angiosperms on the one hand, and the 

 simpler Cryptogams on the other. The relations between 

 G-ymnosperms and Angiosperms have already been briefly 

 discussed in Part I. Chap. IV. 



As regards the male organs, the comparison has 

 been drawn above (p. 18). We need only recapitulate 

 the results here. We found that the development and 

 structure of the microsporangium of Selaginella agreed 

 quite exactly with those of a pollen-sac in the Flowering 

 Plants. The microspores formed in the former are 

 developed precisely in the same way, and have just the 

 same structure as the pollen-grains produced in the latter. 



