CHAPTER XIV 



BUDS 



1. We have already learnt that water is a very 

 important constituent of a plant, and especially so of 

 the young tender growing parts, and that to prevent 

 loss of water the leaves and smaller branches are 

 provided with a thin but" waterproof skin, through 

 which are holes (stomas) that can be opened or shut 

 as required, while older parts of the shoot and the 

 roots have a corky covering. 



These protective skins do not allow of much ex- 

 pansion and are not therefore suitable for the young- 

 est actively growing ends of the branches, which 

 are, therefore, protected in various other ways. 



In some the delicate growing parts are covered by 

 a coat of thickly matted branched hairs (tomentum 

 generally of a brown colour. 



This we find in ZIZYPHUS (fig. 39), DESMODIUM 

 RUFESCENS, STERCULIA and many tropical trees. 

 But in most herbs and shrubs and in most trees of 

 colder climates the end of the branch is covered with 

 young leaves or with specially formed scales, consti- 

 tuting a bud. 



