THE LEAF-BUD. 



83 



when they are swollen or bursting in Spring. The student will 

 notice a gradual change from the outer scales to the evident 

 leaves or stipules within, as seen in Fig. 273. 

 As a further protection against frost and rain, 

 we find the scales sometimes clothed with 

 hairs, sometimes varnished with resin. This 

 is abundant and very aromatic in the buds of 

 the Balm-of-Gilead and other Poplars. 



247. In regard to position, buds are either 

 terminal or axillary, a distinction already no- 

 ticed. Axillary buds are especially noted as 

 being either active or latent. In the former case 

 they are unfolded into branches at once, or in 

 the Spring following their formation. But 

 latent buds suspend their activities from year 

 to year, or perhaps are never quickened into 

 growth. Axillary buds become terminal so 

 soon as their development fairly commences ; 

 therefore each branch also has a terminal bud, 

 and, like the main axis, is capable of extending 

 its growth as long as that bud remains un- 

 harmed. If it be destroyed by violence or 

 frost, or should it be transformed into a 

 flower-bud, the growth in that direction for- 

 ever ceases. 



248. The suppression of axillary 

 buds tends to simplify the form of the plant. 

 Their total suppression during the first year's 

 growth of the terminal bud is common, as in 

 the annual stem of Mullein and in most peren- 

 nial stems. When axillary buds remain permanently latent, 

 and only the terminal bud unfolds year after year, a simple, 

 branchless trunk, crowned with a solitary tuft of leaves, is the 

 result, as in the Palmetto of our southern borders. 



240. A partial suppression of buds occurs in almost all species, and generally in some 

 definite order. In plants with opposite leaves, sometimes one bud of the pair at each 

 node is developed and the other is suppressed, as in the Pink tribe. When both buds 

 are developed, the branches, appearing in pairs like arms, are said to be brachiate, as in 

 the Labiates. In many trees the terminal buds are arrested by inflorescence each season 



ranch of Pear-tree. 

 The terminal hud <(, having 

 been destroyed, an axillary 

 hud supplied its place, and 

 formed the axis/*, r, Thick- 

 ened branch with flower- 

 buds ; (I, brunch with leaf- 

 buds. 272, <, section of 

 terminal bud ; /, of axillary 

 bud. 



