TJDXDEIL-BEAREUS. 77 



length by growth. When a sticky flat on one side, was similarly 

 placed, the tip of the tendril could not curl beyond the flat surface, 

 but coiled itself into a helix, which, turning to one side, lay flat 

 on the little flat surface of wood. In one instance a portion of 

 tendril three-quarters of an inch in length was thus dragged on 

 to the flat surface by the coiling in of the helix. But the tendril 

 thus acquires a very insecure hold, and generally slips off*: in one 

 case alone the helix subsequently uncoiled itself, and the tip then 

 passed round and clasped the stick. The formation of a helix on 

 the flat side of a stick apparently shows us that the continued 

 striving of the tip to curl itself closely inwards gives the force 

 which drags the tendril round a smooth cylindrical stick. In this 

 latter case, whilst the tendril was slowly and quite insensibly 

 crawling onwards, I several times observed tlirough a lens that 

 the whole surface was not in close contact with the stick; and I can 

 understand the onward movement only by supposing that it is 

 slightly vermicular, or that the tip alternately straightens itself a 

 little and then again curls inwards, thus dragging itself onwards by 

 an insensibly slow, alternate movement, which may be compared 

 to that of a strong man suspended by the ends of his fingers to 

 a horizontal pole, who works his fingers onwards until he can 

 grasp the pole with the palm of his hand. However this may be, 

 the fact is certain that a tendril which has caught a round stick by 

 its extreme point can work itself onwards until it has passed twice 

 or even thrice round the stick, and has permanently grasped it. 



Hanburya Mexicana. — The young internodes and tendrils of this 

 anomalous member of the family revolve in the same manner and 

 at about the same rate with the Echiiiocystis. The stem does not 

 twine, but can ascend an upright stick by the aid of its tendrils. 

 The concave tip of the tendril is very sensitive; after rapidly coil- 

 ing into a loop from a single touch, it straightened itself in 50m. 

 The tendril, when in full action, stands vertically up, with the 

 young projecting extremity of the shoot throAvn a little on one 

 side out of the way; but the tendril bears near its base, on the 

 inner side, a short branch, which projects out at right angles, like 

 a spur, with the terminal half bowed a little downwards. Hence, 

 . as the main vertical branch of the tendril revolves, the spur, from its 

 position and rigidity, cannot pass over the extremity of the shoot in 

 the same curious manner as do the three branches of the tendril 

 of the Echinocystis by stiffening themselves at the proper point, 

 but is pressed laterally against the young shoot in one part of the 

 revolving course, and in another part is carried only a little 



