STEMS 



233 



except that it locates a node, and it is the node that starts 



the stem and root for a new plant. 



A third stem-position may be called the climbing position, 



by which a better exposure of leaves to light may be secured 



than in a prostrate position, but 

 no more free space for leaf dis- 

 play, since the support cuts off 

 the space for display on one side. 

 In fact, a prostrate stem on ex- 

 posed soil is about the equivalent 



FIG. 200. A bean turning about 

 a support. 



FIG. 201. Branch of star-cucumber, with its 

 tendrils in various conditions. 



of a climbing stem in a dense forest, where climbing plants 

 become especially conspicuous, so far as 'leaf display is 

 concerned. 



132. Responses of climbing plants. Climbing stems 

 are often spoken of as " twiners " and " climbers " ; in the 

 former case the stem twining about a support, as the morn- 

 ing-glory, bean (Fig. 200), hop- vine, etc. ; in the latter case 



