66 LEAF-CLIMBERS. Chap. II. 



but moved in a rather irregular course during the 

 day to the light, and from the light at night. The 

 petioles, when well rubbed, showed no power of curv- 

 ing ; nor could I see that they ever clasped any 

 neighbouring object. We have seen in this genus 

 a gradation from species such as T. tricolorum, which 

 have extremely sensitive petioles, and internodes which 

 rapidly revolve and spirally twine up a support, to 

 other species such as T. elegans and T. tuberosum, the 

 petioles of which are much less sensitive, and the in- 

 ternodes of which have very feeble revolving powers 

 and cannot spirally twine round a support, to this last 

 species, which has entirely lost or never acquired these 

 faculties. From the general character of the genus, 

 the loss of power seems the more probable alternative. 



In the present species, in T. elegans, and probably in 

 others, the flower-peduncle, as soon as the seed-capsule 

 begins to swell, spontaneously bends abruptly down- 

 wards and becomes somewhat convoluted. If a stick 

 stands in the way, it is to a certain extent clasped ; but, 

 as far as I have been able to observe, this clasping 

 movement is independent of the stimulus from contact. 



Antirrhine^. In this tribe (Lindley) of the 

 ScrophulariaceaB, at least four of the seven included 

 genera have leaf-climbing species. 



Maurandia Barclayana. A thin, slightly bowed 

 shoot made two revolutions, following the sun, each in 

 3 hrs. 17 min. ; on the previous day this same shoot 

 revolved in an opposite direction. The shoots do not 

 twine spirally, but climb excellently by the aid cf 



