STEMS 



1 i<;. 49. Woodbine in a deciduous forest. 



ment which results in spiral coils, since 

 the tendril is fastened at both ends (Fig. 

 48). This curving and twist- 

 ing of the tendril between its 

 fastened extremities naturally 

 results in two spiral coils run- 

 ning in opposite directions. In 

 this way the stem is fastened 

 to its support by numerous 

 spiral springs. All of these 

 movements and their results 

 may be observed by cultiva- 

 ting a plant such as the star- 

 cucumber, which growls rapidly 

 and has conspicuous and very 

 sensitive tendrils. In the case 

 of the ordinary climbing wood- 

 bine and certain species of ivy, 



J ' FIG. 50. Woodbine clinging to a wall 

 Which cling tO Walls Or tree . by means of tendril suckers. 



