BUDS AND BRANCHES 



133 



[H-H-< ^ nip 



Fig. 150. — Dia- 

 gram of opposite bud 

 scales. 



move the scales one by one, representing the number and 

 position of the pairs by a diagram after the model given in 

 Fig. 150. In the bud of an alternately branched twig the 

 order will be different, and the diagram must be varied ac- 

 cordingly. Do you observe any difference _ 

 as to size and texture between the outer 

 and inner scales ? Notice how the former 

 inclose the tenderer parts within like a 

 protecting wall. In cold climates the outer 

 scales are frequently 

 coated with gum, as in 

 the horse-chestnut, for 

 greater security against 

 the weather. The hickory and various 

 other trees have the inner scales covered 

 with fur or down that envelops the tender 

 bud like a warm blanket. 



149. Nature of the scales. — The posi- 

 tion of the scales shows that they occupy 

 the place of leaves or of some part of a 

 leaf. In expanding buds of the lilac and 

 many other plants, they can be found in 

 all stages of transition, from scales to 

 true leaves. In the buckeye and horse- 

 chestnut, they will easily be recognized 

 as modified leaf stalks (Fig. 151). In the 

 tulip tree, magnolia, India rubber tree, 

 fig, elm, and many others, they represent 

 appendages called stipules, often found at 

 the bases of leaves. (See 165, 166.) In 

 this case a pair of scales is attached with 

 each separate leaflet, and as the growing axis lengthens in 

 spring, they are carried apart by the elongation of the inter- 

 nodes so that the scars are separated, a pair at each node, 

 making rings all along the stem, as shown in Fig. 152, in- 

 stead of having them compacted into bands at the base of 



Fig. 151.— Devel- 

 opment of the parts of 

 the bud in the buckeye, 

 (After Gray.) 



