BUDS AND BRANCHES 101 
94. Structure of winter buds. The scaly buds of our com- 
mon trees and shrubs are readily picked to pieces as soon 
as they begin to swell in early spring, but it is easier to dis- 
tinguish the parts of which they are composed by watching 
the opening process from the very beginning. Sections of 
buds, if carefully made, show very clearly the relations of the 
parts (fig. 85). In a leaf bud there are, on the outside, the 
leathery bud scales; inside of these are rudimentary leaves ; 
Fie. 87. Cottonwood twigs, April 15 
The flower buds on the lower twig (developing into catkins) are fully open, but 
the leaf buds are still closed. Reduced 
and within and below the leaves is a central axis tipped with 
a growing point composed of rudimentary cells capable of rapid 
division and growth. 
The scales which cover buds are often the dwarfed and 
otherwise modified leaves or leafstalks, as is well shown in 
some buckeyes and in roses in which the opening buds present 
a series of gradations between mere scales and foliage leaves 
(fig. 76). In other cases, as in oaks, beeches, lindens, and 
magnolias, the scales represent the appendages (stipules) found 
at the bases of many leaves. Frequently bud scales are cov- 
ered with a dense layer of hairs or down, and sometimes, as in 
