TENDIilL-BEAKERS. 53 



account for the circumstance. Nevertheless the plant readily 

 ascends a thin upright stick by its two opposite tendrils, both 

 seizing the stick some way above, and afterwards spirally con- 

 tracting. If the tendrils seize nothing, they do not contract 

 spirally. Bignotiia venusta ascended a vertical stick by spirally 

 twining and by seizing it alternately with its two tendrils like a 

 sailor pulling himself up a rope hand over hand ; our present 

 species pulls itself straight up, like a sailor seizing with both 

 hands together the rope above his head. 



The tendrils are almost identical in structure with those of the 

 last species. They continue growing for some time, even after 

 clasping an object, and when fully grown, though borne by a young 

 plant, were 9 inches in length. The three divergent toes are 

 shorter relatively to the tarsus than in the former species ; they 

 arc blunt at their tips and but slightly hooked; they are not 

 quite equal in length, one being rather longer than the others. 

 The outer surfaces of the three toes are highly sensitive ; for when 

 lightly rubbed with a twig, they became perceptibly curved in 4 m. 

 and greatly curved in 7 m. ; in 7 h. they became straight again and 

 ready to react. The tarsus, for a space of one inch close to the 

 toes, is sensitive, but in a rather less degree than the toes ; for 

 after a slight rubbiug this part required about twice as long a 

 1 ime to bend. Even the middle part of the tarsus, if acted on 

 soon after the tendril has arrived at maturity, is sensitive to pro- 

 longed contact. After the tendrils have grown old, the sensitive- 

 ness is confined to the toes, when they will only curl very slowly 

 round a stick. The maturity of the tendril is shown by the 

 divergence of the three toes, at which period their outer sur- 

 faces first become irritable. The irritability of the tendril has 

 little power of spreading from one part to another: thus, when 

 a stick was caught by the part immediately beneath the three 

 toes, these often remained sticking out, and never clasped the 

 stick. 



The tendrils revolve spontaneously. The movement begins 

 before the tendril is converted into a grapnel by the divergence 

 of the toes, and before any part has become sensitive ; so that the 

 revolving movement is at this early period quite useless. The move- 

 ment is at this time slow, two ellipses being completed conjointly 

 in 24 h. is m. When the tendril was mature, an ellipse was per- 

 formed in G h. ; so that even at this period the movement is 

 much slower than that of the internodes. Large ellipses were 

 swept, both in vertical and horizontal planes, by the tendrils. 



