Cuap. IL. LOPHOSPERMUM. 71 
either a complete or half a turn round it, and ultimately 
increase much in thickness. They do not possess the ” 
power of spontaneously revolving. 
Lophospermum scandens, var. purpureum.— Some 
long, moderately thin internodes made four revolu- 
tions at an average rate of 3 hrs. 15m. The course 
pursued was very irregular, namely, an extremely 
narrow ellipse, a large circle, an irregular spire or a 
zigzag line, and sometimes the apex stood still. The 
young petioles, when brought by the revolving move- 
ment into contact with sticks, clasped them, and soon 
increased considerably in thickness. But they are not 
quite so sensitive to a weight as those of the Rhodochi- 
ton, for loops of thread weighing one-eighth of a grain 
did not always cause them to bend. 
This plant presents a case not observed by me in 
any other leaf-climber or twiner,* namely, that the 
young internodes of the stem are sensitive to a 
touch. When a petiole of this species clasps a stick, 
it draws the base of the internode against it; and then 
the internode itself bends towards the stick, which is 
caught between the stem and the petiole as by a pair 
of pincers. The internode afterwards straightens itself, 
excepting the part in actual contact with the stick. 
Young internodes alone are sensitive, and these are 
sensitive on all sides along their whole length. I made 
* I have already referred to the Vries (ibid. p. 322) is sensitive to 
case of the twining stem of Cus- a touch like a tendril. 
cuta, which, according to H. de 
