viticella, and act in the
same manner like a hook, as will be described under that species.
But the leaflets are more divided, and each segment whilst young
terminates in a hardish point, which is much curved downwards and
inwards; so that the whole leaf readily catches hold of any
neighbouring object. The petioles of the young terminal leaflets are
acted on by loops of thread weighing 0.125th and even 0.0625th of a
grain. The basal portion of the main petiole is much less sensitive,
but will clasp a stick against which it presses.
The leaves, whilst young, are continually and spontaneously moving
slowly. A bell-glass was placed over a shoot secured to a stick, and
the movements of the leaves were traced on it during several days. A
very irregular line was generally formed; but one day, in the course
of eight hours and three quarters, the figure clearly represented
three and a half irregular ellipses, the most perfect one of which
was completed in 2 hrs. 35 m. The two opposite leaves moved
independently of each other. This movement of the leaves would aid
that of the internodes in bringing the petioles into contact with
surrounding objects. I discovered this movement too late to be
enabled to observe it in the other species; but from analogy I can
hardly doubt that the leaves of at least C.
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