Amphicarpcea 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 some time. 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 .015 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 che 

 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 



