LEAF BUDS AND FLOWER BUDS 



83 



irregular positions, as on roots, on unusual parts of the stem, or 

 on leaves (Fig. 88), are called adventitious buds. 



98. Leaf buds and flower buds ; the bud an undeveloped 

 branch. Buds are of three principal classes : leaf buds, in which 

 the parts inside of the scales develop into leaves, and their cen- 

 tral axes into stems ; mixed buds, which contain both leaves and 

 flowers in an undeveloped condition ; and flower buds, which 

 contain the rudiments of flowers only. 



Sometimes, as in the black walnut and the butternut, the 

 leaf buds and flower buds are readily distinguishable by their 



A B 



FIG. 82 



A, a pear leaf bud in autumn; 7>, a leafy shoot-derived from A, as seen in the 

 middle of the following summer, with flower bud at tip; C, the fruit spur, B, 

 in autumn, after the fall of the leaves. After Percival 



difference in form ; while in other cases, as in the cultivated 

 cherry, the difference in form is but slight. In many plants, as 

 the lilac, there is a notable difference in size. 



The rings of scars about the twig, shown in Figs. 79 and 84, 

 mark the place where the bases of bud scales were attached. 

 A little examination of the part of the twig which lies above 

 this ring, as shown in Fig. 79, will lead one to the conclu- 

 sion that this portion has all grown in the one spring and sum- 

 mer since the bud scales of that particular ring dropped off. 



