124 



FOtrNDATIONS OF BOTAIHY 



by their difference in form, while in other cases, as in the 

 cultivated cherry, the difference in form is but slight. 

 The rings of scars about the twig, shown in Figs. 82 

 and 85, mark the place where the bases 

 of bud-scales were attached. A little 

 examination of the part of the twig 

 which lies outside of this ring, as shown 

 in Fig. 82, will lead one to the conclu- 

 sion that this portion has all grown in 

 the one spring and summer since the 

 bud-scales of that particular ring dropped 

 off. Following out this suggestion, it is 

 easy to reckon the age of any moder- 

 ately old portion of a branch, since it is 

 equal to the number of segments between 

 the rings. In rapidly growing shoots of 

 willow, poplar, and similar trees, 5 or 10 

 feet of the length may be the growth of 

 a single year, while in the lateral twigs 

 of the hickory, apple, or cherry the yearly 

 increase may be but a fraction of an inch. 

 Such fruiting " spurs " as are shown in 

 Fi^. 85 are of, little use in the permanent 

 growth of the tree, and poplars, elms, 

 soft maples and other trees shed the 

 oldest of these every year. Whatever 

 the amount of this growth, it is but the 

 lengthening out and development of the 

 bud, which may be regarded as an undeveloped stem or 

 branch, with its internodes so shortened that successive 

 leaves seem almost to spring. from the same point. 



II 



Fig, 84. — Accessory 

 Buds of Butternut. 

 (Eeduoed.) 



I, leEtf-scar ; ax, axil- 

 lary bud : a, a', ac- 

 cessory buds; t, 

 terminal bud. 



