144 TENDRIL-BEARERS. Cnap, IV. 
sensitive, for a slight rubbing produced no effect, al- 
though prolonged contact with a stick caused it to bend. 
The two branches are sensitive on all sides, so that they 
converge if touched on their inner sides, and diverge 
if touched on their outer sides. Ifa branch be touched 
at the same time with equal force on opposite sides, 
both sides are equally stimulated and there is no move- 
ment. Before examining this plant, I had observed 
only tendrils which are sensitive on one side alone, 
and these when lightly pressed between the finger and 
thumb become curved; but on thus pinching many 
times the tendrils of the Cissus no curvature ensued, 
and I falsely inferred at first that they were not at all 
_ sensitive. 
Cissus antarcticus—The tendrils on a young plant 
were thick and straight, with the tips a little curved. 
When their concave surfaces were rubbed, and it was 
necessary to do this with some force, they very slowly 
became curved, and subsequently straight again. 
They are therefore much less sensitive than those of 
the last species; but they made two revolutions, fol- 
lowing the sun, rather more rapidly, viz., in 3 hrs. 30m. 
and 4 hrs. The internodes do not revolve. 
Ampelopsis hederacea (Virginian Creeper).—The inter- 
nodes apparently do not move more than can be 
accounted for by the varying action of the light. The 
tendrils are from 4 to 5 inches in length, with the main ' 
stem sending off several lateral branches, which have 
their tips curved, as may be seen in the upper figure 
(fig. 11). They exhibit no true spontaneous revolving 
