88 
The Ohio Naturalist. 
[Vol. IV, No. 4, 
expansions honiologons to the expansions found in Zostera and 
other genera of the Helobiae. 
It appears to the writer that the supposition that all so-called 
cotyledons are honiologons is probably erroneous. The type of 
embryo found in Sagittaria and Alisina is in fact rather excep- 
tional among Monocotyls and must be regarded as ideal rather 
than typical of the class. Neither is the fact that the plumule 
develops as a terminal structure to be regarded as at all conclusive 
for it is said that the plumules in Dioscoreaceae and Commelina- 
ceae are apical. There are also a number of fundamentally differ- 
ent tj-pes of Dicotyl embryos. Instead of having two general 
types in Angiosperms there are several types, and the.se approach 
each other at various points in widely separated orders. The 
division line between ^Ionocotyls and Dicotyls is, after all, not 
Fig. 2. Diagram of relationship between Helobiae, Nyniphaeaceae and 
Ranales. 
very distinct. Although Angiosperms are far removed from all 
other plants, they represent such a vigorous modern group that 
there has not been time for the extinction of intermediate forms. 
With the removal of a few connecting groups it would be more 
easy to recognize .six or seven classes of Angiosperms instead 
of two. 
With our increasing knowledge of the embryogeny of Angios- 
perms it is becoming more and more apparent that the mere 
difference in the character of the embr3’o is not sufficient to deter- 
mine the position of a genus or family. All pos.sible characters 
