CHARACTERISTICS AND GROWTH. 



47 



the bud is well supplied with nourishment in spring by the stem 



on which it rests, its axis elongates rapidly ; and although the 



growth commences with the lowest internode, yet 



the second, third, and fourth internodes may 



begin to lengthen long before the first has attained 



its full growth. Such very strong buds are usually 



terminal ; but sometimes, as in Lilac (Fig. 86), they 



are the uppermost axillary, which take the place of 



a suppressed or abortive terminal bud. 



82. Such woody stems, developed from a strong 

 bud, and terminated at the close of the season's 

 growth by a similar bud, may be continued from 

 year to year in an unbroken series. A set of narrow 

 rings on the bark (Fig. 85 a) commonly marks 

 the limit of each year's growth. These are the 

 scars left by the fall of the scales of the bud ; and 

 these, in the Horsechestnut, and in other trees with 

 large scaly buds, may be traced back on the stem 

 for a series of years, growing fainter with age, 

 until they are at length obliterated by the action of 

 the weather and the distention caused by the increase 



of the stem in diameter. The same is the case with the more 

 conspicuous Leaf-scars, or marks on the bark left by the separation 

 of the leaf-stalk, which are for a long time conspicuous on the 

 shoots of the Horsechestnut (Fig. 85 b) , the Magnolia (Fig. 81) , 

 and Hickory, Fig. 91. 



83. Ramification. BRANCHES (14-16) are secondary stems 

 developed from a primary one, or tertiary ones from these, and 

 so on. Ultimate or small ramifications of latest order are some- 

 times called BRANCHLETS. The terminal bud continues the stem 

 or axis which bears it. Lateral buds give rise to branches. 1 

 As the normal lateral buds are axillary (75), so are normal 

 branches. The symmetry or arrangement of branches, being 

 that of the buds from which they are developed, is fixed by and 

 follows that of the leaves. When the leaves are alternate, the 



1 Dichotomy or forking, the division of an apex into two, although of com- 

 mon occurrence in the lower cryptoganious plants, occurs so rarely and 

 exceptionally, if at all, in phaenogamous plants that it may here be left 

 out of view. 



In phasnogamous plants only the ramification of axes should take the 

 name of branches. That is, roots and stems branch ; and the term may 

 without confusion be extended to hairs and all THICHOMES (383) when com- 

 pound, but not to leaves and their modifications. 



FIG. 91. End of a Hickory branch (Carya alba), with a strong terminal and smaller 

 axillary buds. 



