once completely clasped a stick, if this is removed, they do not
straighten themselves. The most remarkable fact, and one which I
have observed in no other species of the genus, is that the filaments
and the petioles of the young leaves, if they catch no object, after
standing for some days in their original position, spontaneously and
slowly oscillate a little from side to side, and then move towards
the stem and clasp it. They likewise often become, after a time, in
some degree spirally contracted. They therefore fully deserve to be
called tendrils, as they are used for climbing, are sensitive to a
touch, move spontaneously, and ultimately contract into a spire,
though an imperfect one. The present species would have been classed
amongst the tendril-bearers, had not these characters been confined
to early youth. During maturity it is a true leaf-climber.

Tropaeolum azureum.--An upper internode made four revolutions,
following the sun, at an average rate of 1 hr. 47 m. The stem twined
spirally round a support in the same irregular manner as that of the
last species. Rudimentary leaves or filaments do not exist. The
petioles of the young leaves are very sensitive: a single light rub
with a twig caused one to move perceptibly in 5 m., and another in 6
m. The former became bent at right angles in 15 min., and became
straight again in between 5 hrs. and 6 hrs. A loop of thread
weighing 0.125th of a grain caused another petiole to curve.

Tropaeolum pentaphyllum.--This species has not the power of spirally
twining, which seems due, not so much to a want of flexibility in the
stem, as to continual interference from the clasping petioles. An
upper internode made three revolutions, following the sun, at an
average rate of 1 hr. 46 m. The main purpose of the revolving
movement in all the species of Tropaeolum manifestly is to bring the