STEMS AND BRANCHES AND THEIR USES 



189 



considerable height is a tree. One whose main stem remains 

 short and gives rise near the ground to several branches is a 

 shrub. The distinction between herbs, shrubs, and trees is 

 an old and a convenient one, but it is purely artificial. One 

 cannot distinguish sharply between herbs and woody plants, 

 because practically all stems contain some wood and because 

 there are all possible transitions between very soft and very 



Fig. 116. — A shrub — the pussy willow {Salix discolor). . Photograph 

 by R. H. Denniston and G. Kemmerer. 



hard stems. Likewise there is no hard and fast line between 

 trees and shrubs. Some plants may grow either into trees 

 or into shrubs, depending upon the conditions surrounding 

 them. 



210. Branched and Unbranched Stems. — Indian com 

 usually has no branches excepting the short ones that bear 

 flowers — that is, the ears and tassels. Most other mono- 

 cotyledons, like the com, branch little or not at all above 

 ground, except in their flower-bearing parts ; although some, 



