BUDS AND BRANCHES 



135 



Fig. 153. — Bud development 

 of beech : a, as it is, many buds 

 failing to develop ; b, as it would 

 be if all the buds were to live. 



less zigzag axis that generally characterizes trees of these 

 species. (Fig. 153.) 



152. Forked stems. — Take a twig of buckeye, horse- 

 chestnut, or lilac, ;uul make a care- 

 ful sketch of it, showing all the 

 points that were brought out in the 

 examination of your previous speci- 

 men. Which is the larger, the lat- 

 eral or the terminal bud ? Is their 

 arrangement alternate or opposite ? 

 What was the leaf arrangement? 

 Count the leaf traces in the scars ; 

 are they the same in all ? If all the 

 buds had developed into branches, 

 how many would spring from a 

 node ? Look for the rings of scars 

 left by the last season's bud scales. 

 Do you find any twig of more 

 than one year's growth, as measured by the scar rings? 

 Look down between the forks of a branched stem for a 

 round scar. This is not a leaf scar, as we can see by its 

 shape, but one left by the last season's 

 flower cluster. The flower, as we know, 

 dies after perfecting its fruit, and so a 

 flower bud cannot continue the growth of 

 its axis as other buds do, but has just the op- 

 posite effect and stops all further growth in 

 that direction. Hence, stems and branches 

 that end in a flower bud cannot continue 

 to develop their main axis, but their growth 

 is usually carried on, in alternate-leaved 

 stems, by the nearest lateral bud, or in 

 opposite-leaved ones, by the nearest pair 

 of buds. In the first case there results the zigzag spray 

 characteristic of such trees as the beech and elm (Fig. 155, 

 B) ; in the second, the two-forked, or dichotomous branching, 



Fig. 154. — Two- 

 forked twig of horse- 

 chestnut. 



