348 Sc /lively — Contributions to the Life History of 



tions of sunshine and shade, and having abundant moisture, 

 will produce all three varieties of flower. Tall, vigorous 

 plants, with such environment, seem to excel in quantity 

 of purple flowers. 



2. Plants growing in almost perpetual shade, or those 

 exposed to constant sunshine, even if well supplied with 

 moisture, rarely produce purple flowers, and but few green 

 aerial ones. The subterranean fruits are quite abundant ; 

 but the quality and quantity depend upon the character of 

 the soil. Loose, rich, forest soil, with many decaying 

 leaves, gives excellent results, for the terrestrial fruits may 

 then develop from overground as well as underground 

 runners. 



Along the banks of the Wissahickon, not far from Chest- 

 nut Hill, lies a certain strip of land about a quarter of a 

 mile in extent. It is an open space, not shaded by trees, 

 and is a perfectly luxuriant mass of vegetation, abounding 

 in tall weeds of various kinds, also a few shrubs. The 

 stream is narrow, and the high banks upon the opposite 

 side give a due amount of shade in the afternoon. The 

 soil is loose, very wet and sandy. Plants of Amphicarpcea 

 monoica growing here are most vigorous specimens, rising 

 to the height of six and eight feet, and are densely covered 

 with ferruginous hairs. The best supply of purple flowers 

 was found here, and the racemes were often compound. 

 Strange to say the underground legumes were compara- 

 tively few, and most of them small. 



Does, then, the number of purple flowers affect the pro- 

 duction of underground cleistogamic ones? Or is it due 

 to the character of the soil ? It has also been noticed that 

 those plants giving abundant results in the way of subter- 

 ranean fruits, possessed more tubercles upon the roots. 

 These were quite insignificant, both as to quantity and size 

 upon the Wissahickon plants. Whether this is a mere coin- 

 cidence, or whether there is a real physiological connection, 

 can not now be definitely decided. 



One need, however, pass but a short distance up the 



