Their complicated
circumnutating movements during the day have
[page 308]
been described in the first chapter. The experiment was a superfluous one,
but pots with seedlings of O. rosea and floribunda were turned upside down,
as soon as the cotyledons began to show any signs of sleep, and this made
no difference in their movements.
Leguminosae.--It may be seen in our list that the cotyledons of several
species in nine genera, widely distributed throughout the Family, sleep at
night; and this probably is the case with many others. The cotyledons of
all these species are provided with a pulvinus; and the movement in all is
continued during many days or weeks. In Cassia the cotyledons of the ten
species in the list rise up vertically at night and come into close contact
with one another. We observed that those of C. florida opened in the
morning rather later than those of C. glauca and pubescens. The movement is
exactly the same in C. mimosoides as in the other species, though its
subsequently developed leaves sleep in a different manner. The cotyledons
of an eleventh species, namely, C.
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