In April Weather 59 
scales are too small to leave well-defined marks. 
But in maples and horse-chestnuts the marks 
of the bud-scales of vanished springs are easily 
seen. The spaces between them vary from one 
inch to six or eight, for growth differs in differ- 
ent years, in different trees, or in different branches 
of the same tree, according to the humidity and 
heat of the season, the richness of the soil, or the 
inherent vigor of the individual. 
At the very heart of each bud which tips a 
cf 
bough or twig is the ‘‘apex of growth,’’ a group 
of generative cells on whose strength and activity 
the prolongation of the branch depends. The ex- 
tension of the bough for the season is over and 
done at a comparatively early period. In many 
trees it is completed a month after the first little 
leaves unfold. 
By mid-July even the most procrastinating of 
trees and shrubs have made the growth of the 
year, and formed next season’s buds. Their sub- 
sequent efforts are devoted to perfecting and 
strengthening the young parts, and to laying by a 
store of nourishment against the needs of another 
spring. 
A leaf-bud is generally formed just above the 
foot-stalk of a leaf. On a very young branch the 
