Amphicarpea monotca. 29 
which are destined to produce indurated tissue; other factors 
suppress any such tendency. Yet it has been shown that 
some intrinsic properties firmly hold their own, provided the 
special legume is allowed to attain a sufficient degree of develop- 
ment in a definite natural environment, before being subjected 
to a new one. 
We are thus able to trace gradual transitions in the structure 
of the flowers of the legumes and of the seeds, while we are like- 
wise able to prove experimentally what external agents greatly 
modify the results in various cases. It is evident, therefore, that 
the subterranean seed habit must have originated in response 
to some extrinsic conditions, and our observation of the plant 
in its native haunts must convince us that the above-named 
characteristic has now become an inherited one. 
In conclusion I will call attention to another line of inves- 
tigation which Amphicarpea has presented. During the lat- 
ter part of August, 1897, Professor Macfarlane observed in the 
neighborhood of Strafford Station on the main Pennsylvania 
Railroad (about twenty miles from Philadelphia), a number of 
plants which bore w/zfe flowers. He mentioned the fact to 
me, and some time later I visited the spot. The plants were 
then in fruit. Those legumes which resulted from the evident 
flowers (in this instance—white) were almost invariably four- 
seeded. The plants bore many of these, and likewise others 
which, from position and shape, I knew to be the product of 
green aerial flowers ; these were almost invariably three-seeded. 
The plants extended along the roadsides and in the woods 
for about a mile. 
After noting the above facts, I examined again very carefully 
the number of seeds in the legumes of the purple-flowered 
Amplhicarpea, and found that as a rule those legumes pro- 
duced by the colored flowers contained three seeds, but those 
from the cleistogamic only two. The underground legumes 
of the Strafford variety are small, and pale in color; many 
are nearly pure white. As the character of the soil was not 
