TENDRIL-CLIMBERS. 115 



horizontal position, when they begin again 

 to move. 



About a day after a tendril of the wild 

 cucumber has found a support and has at- 

 tached itself, it begins to coil up, drawing 

 the plant closer to the support. Now simple 

 coiling must always be accompanied by the 

 revolving of the end of the tendril as many 

 tunes as there are turns in the coil, or if the 

 end is fastened the tendril must twist that 

 many times. Both these things are impossi- 

 ble in this tendril, for the end is secured, 

 and the continued twisting would soon rend 

 it. A glance at the figure will solve the 

 difficulty. There is a blank place in the 

 centre of the tendril, and there is an equal 

 number of coils on each side of this space. 

 In other words, the lower part of the tendril 

 has coiled in one direction, and the upper 

 part has coiled just as many times in an 

 opposite direction. This simple arrangement 

 occurs in all revolving tendrils. The spiral 

 coiling of the tendrils means more than sim- 

 ply drawing the plant closer to the support. 

 The coils are highly elastic, and during wind 

 storms they stretch and throw the strain 

 nearly equally upon all contiguous tendrils. 

 If the tendrils were straight they would be 



