286 



TYPICAL FLOWERING PLANTS 



Figure 284. — Microphotograph of 

 Sunflower Stem. 



recognized as stems by the buds of new leaves, or the scars 

 of former leaves. Underground stems, called rhizomes 



(ri'zom) or rootstocks, 

 send up aerial stems 

 which live through one 

 season. 



Stems like the water 

 lily, which grow in 

 water, have large air 

 spaces to carry air to 

 the roots that lie in the 

 mud at the bottom of 

 the water. 



The trunks of trees 

 are stems. In evergreen 

 trees (pine, spruce, etc.) 

 the trunk puts out 

 branches, but does not divide, and tapers from base to tip. 

 Such trunks are called exeurrent (Latin, ex, out ; curro, to 

 run). In the case of the 

 elm tree and many others, 

 the trunk itself divides 

 again and again. Such 

 a trunk is called deliques- 

 cent (Latin, de, from ; 

 liquescere, to become liq- 

 uid). 



An interesting com- 

 parison is that between 

 the climbing and twining 

 stems of plants, especially 

 vines, and the sturdy 

 trunks of trees. The 

 morning glory is a plant Figure 285. — Cleft Grafting. 



