note 1: See page 31.]

[Footnote 2: With one class of children, I had much difficulty in making
them understand the difference between simple and compound leaves. I did
not tell them that the way to tell a single leaf was to look for buds in
the axils, but incautiously drew their attention to the stipules at the
base of a rose leaf as a means of knowing that the whole was one. Soon
after, they had a locust leaf to describe; and, immediately, with the
acuteness that children are apt to develop so inconveniently to their
teacher, they triumphantly refuted my statement that it was one leaf, by
pointing to the stiples. There was no getting over the difficulty; and
although I afterwards explained to them about the position of the buds,
and showed them examples, they clung with true childlike tenacity to their
first impression and always insisted that they could not see why each
leaflet was not a separate leaf.]

An excellent way to show the nature of compound leaves is to mount a
series showing every gradation of cutting, from a simple, serrate leaf to
a compound one (Figs. 24 and 25). A teacher, who would prepare in summer
such illustrations as these, would find them of great use in his winter
lessons. The actual objects make an impression that the cuts in the book
cannot give.

[Illustration: FIG. 24.--Series of palmately-veined leaves.]

[Illustration: FIG. 25.--Series of pinnately-veined leaves.]

Let the pupils compare the distribution of the veins in their specimens.
They have already distinguished parallel-veined from netted-veined leaves,
and learned that this difference is a secondary distinction between
monocotyledons and dicotyledons.[1] The veins in netted-veined leaves are
arranged in two ways. The veins start from either side of a single midrib
(_feather-veined_ or _pinnately-veined_), or they branch from a number of
ribs which all start from the top of the petiole, like the fingers from
the palm of the hand (_palmately-veined_). The compound leaves correspond
to these modes of venation; they are either pinnately or palmately
compound.

[Footnote 1: See page 34.]

These ribs and veins are the woody framework of the leaf, supporting the
soft green pulp. The woody bundles are continuous with those of the stem,
and carry the crude sap, brought from the roots, into the cells of every
part of the leaf, where it is brought into contact with the external
air, and the process of making food (_Assimilation_ 4) is