)10] JEFFREY—PTEROPSIDA 409 
ccupied by a large mass of short tracheids, which he has inter- 
reted as a pith of stelar origin. To state that a central mass of 
tissue, which according to the author’s own admission is entirely 
tracheary, is the forerunner of the pith, and proves the origin of 
e latter from tissues of the stele, is apparently a clear case of 
begging the question. _The example of another fossil osmundaceous 
_GWYNNE-VAUGHAN, is equally inconclusive, since the central tissues 
in the two species of this genus described are in a very bad con- 
dition of preservation. Naturally enough, in these obviously 
protostelic representatives of the Osmundaceae, this author found 
no evidence of the presence of foliar gaps. A much stronger 
argument in favor of his view is furnished by the fossil genus 
Osmundites Dunlopi. Here in sections of the very badly pre- 
_ Served stem it was impossible to distinguish clearly any foliar gaps. 
a GWYNNE-VAUGHAN assumes that the obviously much contracted 
_ central cylinder of his Osmundites Dunlopi represents the primitive. 
conditions in the Osmundaceae, and shows that foliar gaps were 
originally absent in this family. It is not less reasonable to sup- 
pose that the nearly contemporary Osmundites skidgatensis from 
the Lower Cretaceous of the western coast of the Dominion of 
2 Similar tissues of the cortex, in reality represents the primitive _ 
condition for the Osmundaceae. All that the fossil evidence 
than they do at the present time, in other words they presented a 
more generalized condition. 
The evidence from the comparative anatomical and develop- 
mental standpoints is, on the contrary, clearly all in one direction. 
Mr. Srynort in a recent article’ has shown that in the genus 
Todea, especially in the filmy subgenus Leptopleris, there is fre- 
*Suynorr, E. W., Foliar gaps in the Osmundaceae. Annals of Botany 24:107- 
118. pls. 11, 12. 1910 
