CHAPTER VI. THE LEAF 
I. THE TYPICAL LEAF AND ITS PARTS 
Materiau. — Leaves of different kinds showing the various modes of 
attachment, shapes, texture, etc. For stipules, leaves on very young 
twigs should be selected, as these bodies often fall away soon after the 
leaves expand. The rose, Japan quince, willow, strawberry, pea, pansy, 
and young leaves of beech, apple, elm, tulip tree, India rubber tree, 
magnolia, knotweed, furnish good examples of stipules. For the different 
orders of leaf arrangement, lilac, maple, spurge, trillium, cleavers (Galium) 
show the opposite and whorled kinds. Elm, basswood, grasses; alder, 
birch, sedges; peach, apple, cherry, show respectively for each group the 
three principal orders of alternate arrangement. 
165. Parts of the leaf. — Examine a young, healthy leaf 
of apple, quince, or elm, as it stands upon the stem, and 
notice that it consists of three parts: a 
broad expansion called the blade; a leaf 
stalk or petiole that attaches it to the 
stem; and two little leaflike or bristle-like 
bodies at the base, known 
as stipules. Make a 
sketch of any leaf pro- 
. . Fic. 177.—A_ tybi- 
vided with all these parts, a1 teat and ite peste: 
\ and label them, respec- % blade; », petiole; 
8, s, stipules. 
tively, blade, petiole, and 
stipules. These three parts make up a per- 
fect or typical leaf, but as a matter of fact, 
one or more of them is usually wanting. 
wie ETSY 166. Stipules. — The office of stipules, 
when present, is generally to subserve in 
some way the purposes of protection. In many cases, as in 
the fig, elm, beech, oak, magnolia, etc., they appear only as 
protective scales that cover the bud during winter, and fall 
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