OPENING OF BUDS 



205 



In plants, like annuals and those that live in the tropics, the 



buds usually have no protective scales and are called naked buds. 



Scaly buds are characteristic of plants which 



must pass through seasons that are unfavor- 

 able for growth, and may be considered a 



device for maintaining partially developed 



stem portions in a protected state, and in 



readiness to assume rapid growth at the 



opening of the growing season. 



Opening of Buds. — 

 The bud scales are forced 

 open by the growth of 

 the young shoot within. 

 The resumption of 

 growth by the parts en- 

 closed is first shown by 

 the swelling of the bud. 

 When the young shoot which the flowers are 

 resumes growth at the Pushing the scales 

 beginning of the grow- 

 ing season, it grows with Baiigy" 

 remarkable rapidity and 

 in a few days pushes out of its scaly cover- 

 ing. {Fig. 183.) After the shoot has es- 

 caped, the scales usually fall off, leaving a 

 scar about the branch at their place of at- 

 tachment. The bud has now disappeared 

 and in its place there is a new growth bear- 

 ing leaves or flowers, or sometimes both. 



The scars left by the scales remain until 

 the bark is sufficiently developed to obscure 

 them, and serve to indicate the age of the 

 different regions of a branch. In Figure 

 184, the portion beyond the scar (a) is the 

 last season's growth. The portion between 

 (a) and (6) is two years old, and the por- 

 tion between (b) and (c) is three years of 

 age. Thus the age of a given region of 



a branch is indicated by the scars on the branch as well as by 



the annual rings in its woody cyUnder. 



Fig. 183. — Flower 

 bud of the Pear, in 



apart and coming out 

 of the bud. After 



Fig. 184. — Plum 

 branch showing regions 

 of different ages as in- 

 dicated by the scars re- 

 sulting from the falling 

 away of the bud scales. 

 Described in text. 



