42 



STEMS 



57. Growth of the terminal bud. In some trees the termi- 

 nal bud from the outset keeps 

 the lead and produces a slen- 

 der, upright tree (Fig. 33), as 

 in the pines, spruces, and firs. 



In such trees as the apple 

 and many oaks the terminal 

 bud has no preeminence over 

 others, and the form of the 

 tree is round-topped and 

 spreading (Fig. 34). Most 

 forest trees are intermediate 

 between these extremes. 



Branches owe their char- 

 acteristics to several factors. 

 Most of our trees and larger 

 shrubs make a definite annual 

 growth, with the buds ripened 

 before the coming of winter 

 (Fig. 79). In these the ter- 

 minal bud is likely to grow 

 and continue the branch. 

 Such shrubs and trees as the 

 raspberry and blackberry, the 

 sumach and the ailanthus, 

 make an indefinite annual 

 growth, that is, the tips of the 

 branches are usually killed 

 by frost, and so the tree forks 

 often. Terminal flower buds 

 (Figs. 36, 37) also cause fork- 

 ing and allow the tree to form 



i O 



FIG. 33. California giant redwoods no long, straight branches. 



), illustrating upright growth j f the terminal buds of 



After J. H. White branches keep the lead of the 



