12 THE AMERICAN NATURALIST. 
antiquity; but as a whole, the former have remained simpler 
than the dicotyledons. The scattered, closed vascular bundles 
probably represent a more primitive type of structure than the 
ring of open bundles characteristic of the more highly devel- 
oped dicotyledons. 
It is exceedingly important for a clear understanding of the 
affinities of such anomalous types as Podophyllum that a com- 
plete study should be made of the development of the embryo 
sac and embryo. Results of importance ought to reward the 
student who will make a critical study of the development of 
these puzzling forms. 
LELAND STANFORD JR. UNIVERSITY. 


