SCHIZAEACEAE 549 
bearing on this the development of its seedling does not suggest reduction 
from any more complicated type. In the seedling of Amezmia there is 
at first a solid stele, which is converted into a dialystelic one by gradations 
similar to those for instance in Péeris: the ontogeny may here be held 
to indicate the probable evolutionary progression. In the case of Schizaea 
FIG. 307. 
Transverse section of axis of seedling of Lygodium japonicum, below the first leaf. Z=one 
of the xylem-parenchyma cells. X390. (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: 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 2 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, /.c., p. 2. 2Z.e, p. 148. 
