SCHIZAEACEAE 



549 



bearing on this the development of its seedling does not suggest reduction 

 from any more complicated type. In the seedling of Ancimia there is 

 at first a solid stele, which is converted into a dialystelic one by gradations 

 similar to those for instance in Pteris : the ontogeny may here be held 

 to indicate the probable evolutionary progression. In the case of Schizaea 



KIG. 307. 



Transverse section of axis of seedling of Lygodiuinjaponicitin, below the first leaf. / = one 

 of the xylem-parenchyma cells, x 390. (After Boodle.) 



the facts, indicate that its middle position is due to amplification of the 

 stele leading up towards the solenostelic state, though the opinion is also 

 a tenable one that the genus illustrates phases of reduction. 



EMBRYOLOGY. 



This is described as being similar to that common for most Ferns in 

 the case of Schizaea pusilla. 1 It may be noted, however, that the fila- 

 mentous prothallus in this species shows very close analogies with that of the 

 Hymenophyllaceae 



In discussing the probable phyletic relations of the living Schizaeaceae, 

 Prantl - remarks that it is impossible to derive any one genus from any other : 

 they have obviously similar soral and sporangial characters, but they differ 

 so greatly one from another in other respects that we can only regard them 

 as derived from some simpler type, which may be held as a common 



1 Britton and Taylor, I.e., p. 2. -/..<., p. 148. 



