Amphicarpea monoica. 23 
are not readily discernible. Anthocyanin is irregularly dif- 
fused through the outer parenchymatous cells. The purple 
hue deepens as maturity approaches. The average number 
of mesophyll cells is six, but occasionally eight are found. 
The plastids seen here are of the same size as the chloroplas- 
tids observed in the aerial legume, but one or two only are 
found in a cell of the subterranean, ten or twelve in a cell of 
the aerial legume. The legume walls become brown after 
they remain under ground for sometime. I think this must 
be partly due to excess of water supply, for legumes which I 
have kept in slightly moistened earth retained the purple 
color for some weeks. Subterranean legumes never dehisce. 
SUBTERRANEAN SEEDs. 
The seed-coat exhibits an epidermal structure which both in 
form and possession of color closely resembles the conditions 
described for the aerial seed. Excepting this, no other indur- 
ated tissue is to be observed in the subterranean seed coat. 
The cells of the cotyledons measure .15 of a millimetre. The 
arrangement and contents of the epidermal cells are similar to 
those in the aerial seed; these cells too are smaller than 
those in the remaining portion of the cotyledons. The starch 
granules are ellipsoidal and measure .o15 of a millimetre. 
Protein granules are more numerous in the older seed than in 
the younger specimens; in the latter, starch is comparatively 
more abundant. It is suspected that the same condition of 
affairs may be found by comparing aerial seeds of different 
ages, but unfortunately no material in young condition was at 
hand. If these facts should prove true, we have evidence of 
the accumulation of the carbohydrate earlier than that of the 
nitrogenous compounds. 
EXPERIMENTS. 
It had been discovered that the green aerial legumes result- 
ing from the aerial cleistogamic flowers might, by being buried 
in soil, be converted into others of a purple color and swollen 
