BRANCHING STEMS 



175 



developed, starts out in life with superior advantages of 

 position. Then, too, in ordinary upright stems the sap 

 flow is strongest in the upper part of the stem, as may 

 be shown by selecting two healthy seedlings as nearly as 

 may be of the same size and height, inverting one of them 

 as described in Section 1 59, and keeping it in this position 

 for several days by tying or by attaching a weight to it, 

 while leaving the other upright. Watch their growth for 

 a week or ten days and note results. 



Make a drawing of your specimen, showing all the 

 points brought out in the examination just made. Cut 

 sections above and below a set of bud scars and count 

 the rings of annual growth in each section. What is the 

 age of each .■' How does this agree with your calculation 

 from the number of scar rings .'' 



245. Irregularities. — Take a larger bough of the same 

 kind that you have been studying, and observe whether 

 the arrangement of branches 

 on it corresponds with the 

 arrangement of buds on the 

 twig. Did all the buds develop 

 into branches .' Do those that 

 did develop all correspond in 

 size and vigor ? If all the buds 

 developed, how many branches 

 would a tree produce every 

 year .'' 



In the elm, linden, beech, 

 hornbeam, hazelnut, willow, 

 and various other plants, the 

 terminal bud always dies and 

 the one next in order takes its 

 place, giving rise to the more 

 or less zigzag axis that generally characterizes trees of 

 these species. 



246. Forked Stems. — Take a twig of buckeye, horse- 

 chestnut, or lilac, and make a careful sketch of it, show- 



324. — Bud development of beech : 

 a, as it is, many buds failing to de- 

 velop ; d, as it would be if all the 

 buds were to live. 



