TWINERS AXD CLIMBERS. 219 



Reflecting upon these movements we are prepared 

 to assent to the concluding paragraph of the work in 

 which most of the observations in this chapter have 

 been founded. " It has often been vaguely asserted 

 that plants are distinguished from animals by not 

 having the power of movement. It should rather be 

 said that plants acquire and display this power only 

 when it is of advantage to them ; this being of com- 

 paratively rare occurrence, as they are affixed to the 

 ground, and food is brought to them by the air and 

 rain. We see how high in the scale of organization 

 a plant may rise, when we look at one of the more 

 perfect tendril-bearers. It first places its tendrils 

 ready for action, as a polypus places its tentacula. If 

 the tendrils be displaced it is acted on by the force of 

 gravity and rights itself It is acted on by the light 

 and bends towards or from it, or disregards it, which- 

 ever may be most advantageous. During several 

 days the tendrils or intcrnodes, or both, spontaneously 

 revolve with a steady motion. The tendril strikes 

 some object, and quickly curls round and firmly 

 grasps it. In the course of some hours it contracts 

 into a spire, dragging up the stem and forming an 

 excellent spring. All movements now cease. By 

 growth the tissues soon become wonderfully strong 

 and durable. The tendril has done its work, and 

 has done it in an admirable manner." ^ 



' Darwin, " ]Movements of Climbing Plants," p. 206. 



