CLIMBING PLANTS. 413 
Echinocystis lobata. A thin, smooth, cylindrical, stick 
was placed so far from a tendril that its extremity could 
only eurl half or three-quarters round the stick. It was 
always found in the course of a few hours afterwards that 
the tip had managed to curl twice or even thrice quite round 
the stick. . Measurements showed that this was not due to 
the growth of the tendril. Whilst the tendril was slowly 
and quite insensibly crawling onwards it was observed that 
the whole surface was not in close contact with the stick. 
The onward movement is supposed to be slightly vermicular, 
or that the tip alternately straightens itself a little and then 
again eurls inwards, thus dragging itself onwards by an in- 
sensibly 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. Experiments 
upon this interesting plant were made and the results pub- 
lished by Dr. Asa Gray, in 1858. This led Mr. Darwin to 
more extended observations upon many other climbing 
plants. He is only one of a large number of persons who 
are indebted for valuable hints from the sagacious botanist 
of Cambridge, Mass. 
Hanburya Mexicana. In a few days after the tips of the 
tendrils have grasped an object the inferior surface swells 
and becomes developed into a cellular layer, which adapts 
itself closely to the wood, and firmly adheres to it. This is 
not the extreme tip of the tendril but a trifle back of it. 
This layer apparently secretes some resinous cement, as it is 
not loosened by water or alcohol, but is freed by the action 
of ether and turpentine. 
Tendrils of plants belonging to Vitacee, Sapindacem, 
assifloracee, and perhaps others, are modified flower pe- 
duneles, but their homological nature makes no difference in 
their action. Figure 89 shows part of the tendril of a grape- 
vine bearing flowers. From this state we can trace every 
stage till we come to a full-sized common tendril, bearing on 
