OTHER STEMS 



289 



Figure 291. — Types of Twigs. 



a, maple; b, elm; c, walnut; d, catalpa 

 e, ash ; /, linden. 



contain both leaves and 

 flowers. As a bud 

 opens, the scales drop 

 off leaving on the twig 

 scars crowded together 

 in indistinct rings. The 

 growth of a twig in the 

 preceding year can be 

 seen by noting the dis- 

 tance between the tip of 

 the twig and the first 

 group of indistinct rings, 

 which marks the posi- 

 tion of the terminal bud of last year. A study of the 

 buds on a branch shows where the new branches will form. 

 The place where the leaves of last year were attached 

 shows on the bark as scars, called leaf scars. In each leaf 

 scar are a number of small dots. These dots are the ends 



of the vascular bundles 

 which grew from the 

 stem into the leaf. 



A cross section of a 

 woody stem shows a 

 central pith surrounded 

 by one or more rings 



Figure 292. — Cherry Twigs. 

 Leaf buds and fruit buds. 



Figure 293. — Sections of 

 Woody Stem. 



of wood. The pith and the bark are connected by narrow 

 lines of pith called medullary rays (Figure i? ( .*3). A 



