Darkness, therefore, during a day and a half does not interfere with
the periodicity of their movements. On a warm but stormy evening, the plant
whilst being brought into the house, had its leaves violently shaken, and
at night not one went to sleep. On the next morning the plant was taken
back to the hot-house, and again at night the leaves did not sleep; but on
the ensuing night they rose in the usual manner between 70o and 80o. This
fact is analogous with what we have observed with climbing plants, namely,
that much agitation checks for a time their power of circumnutation; but
the effect in this instance was much more strongly marked and prolonged.
Colocasia antiquorum (Caladium esculentum, Hort.) (Aroideae).--The leaves
of this plant sleep by their blades sinking in the evening, so as to stand
highly inclined, or even quite vertically with their tips pointing to the
ground. They are not provided with a pulvinus. The blade of one stood at
noon 1 degree beneath the horizon; at 4.20 P.M., 20o; at 6 P.M. 43o; at
7.20 P.M., 69o; and at 8.30 P.M., 68o; so it had now begun to rise; at
10.
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