290 



PLANTS 



where a leaf is attached is called the axil of the leaf. Buds 



and branches are usually formed only in the axils of leaves 



(cf. 315). 

 Stems are of many different sorts. Some are strong 



and stiff, and able to bear a great deal of weight, as is the 



case in trees; some run 

 along the ground, as in 

 the strawberry plant ; and 

 some seek a support, as 

 does the stem of the 

 morning-glory. 



Branches usually are 

 in such positions that the 

 leaves get overhead light. 

 Even when branches be- 

 gin by growing upward, 

 they are commonly 

 pulled down by gravity, 

 as they grow larger, to a 

 more or less horizontal 

 position. 



FIG. 238. A Hickory (Hicoria pecan) 

 Museum of Natural History. 



Field 



In trees the main trunk 

 sometimes grows straight up- 

 ward, as in the poplar and fir 



(cf. Fig. 251, 327), and sometimes is divided again and again, as in 

 the elm (Fig. 236), oak (Fig. 237), beech, and hickory (Fig. 238). As 

 a result of the two kinds of branching, the general outline of a tree 

 may be either cone-shaped or spreading. 



313. Structure of Stems; Wood. If we cut across a 

 growing woody stem, such as a lilac or a maple, we shall 

 be able to make out four distinct regions (Fig. 238a). 



