Chap. H. 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 ccandens, var. purpureum. Some 

 long, moderately thin internodes made four revolu- 

 tions at an average rate of 3 hrs. 15 m. 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, 

 euta, which, according to H. de 



