92 



PRACTICAL BOTANY 



--ax 



83. Position of buds. Buds are either terminal, growing from 

 the tip of the stem ; or lateral, growing from its side (Fig. 74, 

 lat). The plumule (Fig. 126) is the first terminal bud of the 

 young seedling. Commonly the terminal 

 bud is stronger than any of the lateral 

 ones, and makes more rapid growth than 

 they do. 



Lateral buds are usually axillary ; that 

 is, they arise from the axil, or angle, 

 formed by the leaf with the stem, as 

 shown in Fig. 74, ax. Many plants also 

 produce accessory buds; that is, buds a 

 little outside of the leaf axil, which may 

 either stand above the axillary bud, as in 

 the butternut, or on either side of it, as 

 in the box elder (Fig. 75). 



Adventitious buds are those which spring, 

 without any definite order, from roots, 

 stems, or leaves. These are often of great 

 value in propagating plants by means of 

 cuttings or layers. 



84. Form of trees dependent on growth 

 of buds. If the uppermost bud of the main 

 stem of a tree continues year after year 

 to be stronger than any other bud, the 

 general form of the tree becomes roughly 

 conical, as is well shown in the pine tree 

 (Fig. 246), and in firs, spruces, and the 

 European cypress. If, on the other hand, 

 some of the branches grow in length as 

 fast as the main trunk, the tree will be- 

 come round-topped and spreading, like an apple tree, an elm, or 

 most of our hard-wood trees, when they grow in open ground. 

 Not uncommonly the terminal bud of most branches is a 

 flower bud, as in the magnolias, or no terminal bud is devel- 

 oped, as in the lilac. In these cases the main branches cannot 



FIG. 74. Twig of hick- 

 ory in winter condition 



.sc, scar of last year's 

 leaf; lat, a lateral bud; 

 I, a last year's leafstalk ; 

 ax, a lateral bud in the 

 axil of the leafstalk ; t, 

 terminal bud. Reduced 



