Stems and Their External Features 



107 



of the previous year put forth a new set of leaves to replace 



those lost the preceding autumn. As a matter of fact, when 



we look at a deciduous tree 



in winter, we see branches 



and twigs, all of which have 



borne leaves and none of 



which will ever bear leaves 



again. The possibiHty of 



producing new foliage lies 



in the development of new 



branches and twigs. This 



is the function of the buds ; 



from them the new growth 



of each year takes its rise. 



The buds of many tropi- 

 cal plants are like those we 

 see at the tops of the stems 

 of garden vegetables. Such 

 a bud consists of the stem's 

 growing point and the un- 

 developed leaves, with no 

 special coverings of any 

 kind. These naked buds 

 occur also on the under- 

 ground stems of some of 

 our Northern plants. A 

 simple sort of bud covering, 

 which is common in the 

 tropics, is made by the fold- 

 ing together of the stipules. 



This type of bud covering lenticel, / a terminal bud scar, and g a tendril 



Fig. 63. Twigs of smilax (.1), buckeye {B)» 

 and trec-of-hcavcn {Ailanthtis) (C). The 

 bud scales are designated by a ; b and h are 

 buds; c is a leaf scar, d a bundle scar, e a 



