The petiole of a young leaf rose at night 34o, and that of an
older leaf 19o. Owing to the slight movement of the leaflets and the
considerable movement of the petiole, the bush presents a different
appearance at night to what it does by day; yet the leaves can hardly be
said to sleep.
The circumnutating movements of the leaves of C. floribunda, calliantha,
and pubescens were observed, each during three or four days; they were
essentially alike, those of the last-named species being the simplest. The
petiole of C. floribunda was secured to a stick at the base of the two
terminal leaflets, and a filament was fixed along the midrib of one of
them. Its movements were traced from 1 P.M. on August 13th to 8.30 A.M.
17th; but those during the last 2 h. are alone given in Fig. 156. From 8
A.M. on each day (by which hour the leaf had assumed its diurnal position)
to 2 or 3 P.M., it either zigzagged or circumnutated over nearly the same
small space; at between 2 and 3 P.M. the great evening fall commenced. The
lines representing this fall and the early morning rise are oblique, owing
to the peculiar manner in which the leaflets sleep, as already described.
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