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 possibility 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 FlG 63 Twigs of smilax M)> buckeye (B}> 



tropics, is made by the fold- and tree-of -heaven (Ailanthus) (C). The 



ing together of the Stipules. ^ SCalCS are Designated by ; b and h are 



4 * ^ buds; c is a leaf scar, d a bundle scar, e a 



This type Of bud Covering lenticel, / a terminal bud scar, and g a tendril 



