42 



ELEMENTS OF BOTANY. 



Branches get their characteristics to a considerable degree 

 from the relative importance of their terminal buds. If these 

 are mainly flower-buds, as is the case in the horse-chestnut, 

 the tree is characterized by frequent forking, and has no 

 long horizontal branches. 



If the terminal bud keeps the lead of the lateral ones, but 

 the latter are numerous and"^ most of them grow into slender 

 twigs, the delicate spray of the elm and many birches is 

 produced, Fig. 28. 



Fig. 26. — I, An American Elm with Deliquescent Trunk. II, Cottonwood 

 Poplars with Excurrent Trunks. 



The general effect of the branching depends much upon 

 the angle which each branch or twig forms with that one 

 from which it springs. The angle may be quite acute, as in 

 the birch ; or more nearly a right angle, as in the ash, Fig. 24. 



It is these differences that help to give to leafless woods 

 in winter their unending variety and beauty. 



64. Indefinite Annual Growth. — In most of the forest 

 trees, and in the larger shrubs, the wood of the branches is 

 matured and fully developed during the summer, and pro- 



