THE MATURE PLANT 27 



any part of the stem. In case a terminal bud is destroyed, and 

 also under certain other conditions, the development of the 

 main axis may be continued by an axillary bud. Also, if an 

 axillary bud is destroyed its functions may be taken up by ac- 

 cessory or adventitious buds. 



58. Since branches normally develop from axillary buds, it 

 follows that branches are arranged on the stem in conformity 

 with the law which governs the arrangement of the leaves on 

 the stem. 



59. The terminal bud, because of its favorable position with 

 respect to light exposure, and also possibly for other causes, is 

 usually stronger than lateral buds, and therefore the main axis 

 develops more rapidly than the branches. Many lateral buds, 

 on the other hand, are in such unfavorable positions that even 

 after having developed to some extent they are " choked" and 

 the twig dies and falls away. Still others never develop at all. 

 Thus it results that while the position of a branch on the stem 

 is governed by the law of leaf arrangement, yet, because of the 

 large number of buds that do not develop and of others that are 

 choked out, the regularity of arrangement is seldom evident in 

 the case of branches. 



The Mature Plant 



60. At the end of the growing season the foliage leaves of 

 deciduous perennials fall off, leaving a scar on the twig. The 

 bud scale-leaves fall away on the unfolding of the bud and also 

 leave scars, which, however, are so crowded, because of the 

 slight elongation of the axis, that they frequently form a con- 

 tinuous ring around the stem. The scale-leaf scar can also be 

 distinguished from the foliage-leaf scar by its form. The 

 position of the scale-leaf scars indicates the beginning of the 

 year's growth, consequently the age of a twig may be deter- 

 mined by counting the successive rings of scale scars. Other 



