
No. 461] AFFINITIES OF EQUISETUM. 285 
in the two classes, there arose quite independently two types of 
sporophyte : one distinguished by a preponderant development of 
the shoot, the other marked by the great development of the leaf 
structures. 
Neither of these classes is at all related to the Lycopods, 
which show strong evidences of being derived independently 
from a very different type of gametophyte. 
STANFORD UNIVERSITY. 
