104 Elementary Principles of Agriculture 



of the cambium layer is often confined to the east side 

 of a tree where the early sun rays cause a sudden warm- 

 ing. Delicate plants, fruits, etc., may often be saved 

 by protecting from too rapid thawing. By shielding 

 from the sun's rays, bathing in cold water, etc.* 



154. Buds and Nodes. If we examine the branches of 

 almost any shrub or herb, we shall find that they are 

 divided into segments by the buds at the nodes. We have 

 ^already found a reason for calling the former nodes, and 

 the spaces between, internodes. The buds are formed 

 just above, or, as the botanist says, in the axil of the leaf, 

 which readily explains the observation that the vigor 

 of the buds is determined by the size of the leaves which 

 nourish them. The bud at the end of the shoot, called 

 the " terminal bud," is usually the most vigorous; 

 but, as a rule, the vigor and the size of the buds de- 

 crease as we pass down to the beginning of the season's 

 growth. This is often due to the subsequent shading of 

 the lower leaves, often to the extent that they turn 

 yellow and fall off. 



155. Structure and Classification of Buds. If we exam- 

 ine some large buds, such as the buckeye, sycamore, or 

 fig, just as they unfold their leaves in the spring, it 

 will be very plainly seen that the bud scales are only 

 transformed leaves, hence they are called scale-leaves 

 to distinguish them from normal leaves. These scale- 

 leaves cover up an embryo branch a branch having 

 miniature leaves, nodes and internodes. Nature formed 

 these buds, or embryo branches, early in the preceding 

 season. Note also that more buds were formed than are 

 likely to grow into branches. (Fig. 52.) 



*For excellent full discussion of the effects of temperature on plants, and 

 the proper treatment to lighten the bad effects, reference should be made to 

 Goff. The Principles of Plant Culture; Bailey, The Principles of Fruit Culture. 



