96 ELEMENTS OF BOTANY. 
pair below it, and sometimes in the lengthening of the lower 
petioles so as to bring the blades of the lower leaves outside 
those of the upper leaves. Examination of Fig. 80 will make 
the matter clear. 
The student should not fail to study the leafage of several 
trees of different kinds on the growing tree itself, and to 
Fic. 81. — Opposite Leaves of Deutzia1! (from the same shrub as Fig. 82), as 
arranged on horizontal branch. 
notice how circumstances modify the position of the leaves. 
Maple leaves, for example, on the ends of the branches are 
arranged much like those of the horse-chestnut, but they are 
found to be arranged more nearly flatwise along the inner 
portions of the branches, that is, the portions nearer the tree. 
1 Deutzia crenata. 
