STK.MS 



69 



from adventitious or dormant buds on the trunk or limbs. 

 Such spines sometimes show their true nature as branches 

 by bearing leaves (Fig. 34). 



84. Indefinite Annual Growth. In most of the forest 

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

 is matured and fully 



developed during the 1 



summer. Protected 

 buds are formed on 

 the twigs of these 

 branches to their very 

 tips. In other shrubs 

 for example, in the 

 sumac, the raspberry, 

 and blackberry the 

 shoots continue to 

 grow until their soft 

 and immature tips are 

 killed by the frost. 



Such a mode of growth is called indefinite 

 annual growth, to distinguish it from the 

 definite annual growth of most trees. 



85. Trees, Shrubs, and Herbs. Plants 

 of the largest size with a main trunk of a 

 woody structure are called trees. Shrubs 

 differ from trees in their smaller size, and 



generally in having several stems which proceed from the 

 ground or near it or in having much^forked stems. The 

 witch-hazel, the dogwoods, and the alders, for instance, 

 are most of them classed as shrubs for this reason, though 

 in height some of them equal the smaller trees. Some of 



FIG. 34. Leaf-Bearing Spine 

 of Honey Locust. 



