72 LEAF-CLIHBERS. Chap. U. 



fifteen trials by twice or thrice lightly rubbing with a 

 thin twig several intemodes ; and in about 2 hrs., but 

 in one case in 3 hrs., all were bent: they became 

 straight again in about 4 hrs. afterwards. An inter- 

 node, which was rubbed as often as six or seven times, 

 became just perceptibly curved in 1 hr. 15 m., and 

 in 3 hrs. the curvature increased much; it became 

 straight again in the course of the succeeding night, 

 I rubbed some intemodes one day on one side, and 

 the next day either on the opposite side or at right 

 angles to the first side ; and the curvature was always 

 towards the rubbed side. 



According to Palm (p. 68), the petioles of Linaria 

 cirrhosa and, to a limited degree, those of L. elatine 

 have the power of clasping a support. 



SoLANACE^. — Solanvm jasminoides. — Some of the 

 species in this large genus are twiners ; but the present 

 species is a true leaf-climber. A long, nearly upright 

 shoot made four revolutions, moving against the sun, 

 very regularly at an average rate of 3 hrs. 26 m. The 

 shoots, however, sometimes stood still. It is con- 

 sidered a greenhouse plant ; but when kept there, the 

 petioles took several days to clasp a stick: in the 

 hothouse a stick was clasped in 7 hrs. In the green- 

 house a petiole was not affected by a loop of string, 

 suspended during several days and weighing 2J 

 grains (163 mg.) ; but in the hothouse one was made 

 to curve by a loop weighing 1-64 gr. (106'27 mg.) ; and, 

 on the removal of the string, it became straight again. 

 Another petiole was not at all acted on by a loop 



