280 
hiscent. The seeds have a purplish brown membrane and no 
albumen. The embryo is straight. The large, fleshy cotyledons 
are furnished with pulvini and are exceedingly rich in oil. 
General Observations on the Plants Studied. 
The following study was made with plants raised during two 
successive summers in Englewood, N. J.; Lawrence, L. I., and in 
Potsdam and Buffalo, N. Y. In New Jersey and on Long Island 
the plants thrived and produced fruit. The seeds planted in richer 
soil in northern New York produced healthy looking, well-grown 
plants with flowers but no fruit developed. The plants grow best 
in a dry sandy soil, and a warm, at least temperate, climate. 
Under favorable conditions of weather fruit was obtained from 
seeds planted in Lawrence within two months. From two to 
three months is usually required. Plants of a crop raised in 
Lawrence when pulled up during the early part of October were 
found to bear a quantity of tubers on their roots. On other 
plants of the same crop examined in November no tubers were 
found. 
In the nyctotropic movement of the leaves, which has already 
been described by Darwin in his * Power of Movement in Plants," 
the main petiole sinks downward; the leaflets twist downward 
and backward so that the lower surfaces of each pair are applied 
to each other. In this position they form a little packet shutting 
around the petiole, with the superior pair closed over the inferior 
and the tips pointing upward. The leaves vary their positions 
on the stem during the day in such a way as to keep their upper 
surfaces inclined toward the sun. When a leaf was separated 
from the stem so that the water supply was cut off while evapora- 
tion was going on it was discovered that the loss of water made 
itself apparent first in the upper half of the pulvinus of the leaflets- 
When cut at night or at four p. m. the movement was 
quicker, probably because the water in the cells of the upper half 
of the pulvini had already begun to lessen in quantity. The 
leaves of some stems cut in the morning slept after about one-half 
hour; others slept at once. The leaves of stems cut on a hot 
day slept more quickly than those cut on a cool day; those cut 
at about four in the afternoon more quickly than those cut in the 
morning. 
