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TEXTBOOK OF BOTANY 



and all the leaves of a tree or shrub may have been present in some 

 stage of development within the doraiant buds of the preceding season. 

 Adventitious buds. Branches usually develop from buds in the axils of 

 leaves and may be referred to as axillary branches. Branch buds may, 

 however, develop from internodes of young stems, from roots, and even 

 from leaves. These are adventitious buds. Their occurrence on the inter- 

 nodes of stems is often a result of some interference with the growth of 

 the tissues, as injurv or disease. New branches from trunks of trees 



Fig. 84. Cross sections of stems of Virginia crab apple. A, two latent buds, the 

 traces of which extend inward to the first cylinder of xylem. They began as axillary 

 buds on the one-year-old stem and have survived for 13 years. B, a water-sprout 

 has developed from a latent lateral bud. Photo by V. T. Stoutemyer. 



several years old, and sprouts from the base of stumps were formerly 

 thought to develop solely from adventitious buds, but recent investiga- 

 tions have shown that some of them develop from lateral buds that 

 survive in the bark of the tree for many years (Fig. 84). Others start 

 from adventitious buds. Pollarding (Fig. 85) results in the growth of 

 many lateral buds and a dense growth of new branches. A more thorough 

 study will have to be made before one can say whether these new 

 branches on pollarded trees start from latent lateral buds or from 

 adventitious buds. 



Apical dominance. When the terminal bud of a twig is cut off, branches 

 develop from lateral buds that would otherwise have remained donnant 

 or died. Moreover, such branches usually grow from the uppermost 

 lateral buds. This inhibiting influence of the buds nearest the apex over 



