124 FOUNDATIONS OF BOTANY 
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 
Fig. 84. — Accessory 
Buds of Butternut. 
(Reduced.) 
l, leaf-scar ; az, axil- 
lary bud; a, a’, ac- 
cessory buds; ¢, 
terminal bud. 
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 
Fig. 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. 
