some of them: peas and vetches, and some kinds of beans,
violets, balsams, wood sorrel, geranium, castor bean, some of the
mustards and cresses and their cousins, Alfilerilla, richweed,
_Pilea_, witch-hazel, and others. Each of those will well repay study,
especially the fruit and seeds of oxalis. The witch-hazel bears a
hard, woody, nut-like fruit, as large as a hazelnut; when ripe, the
apex gaps open more and more, the sides pressing harder against each
smooth seed, till finally it is shot, sometimes for a distance of
thirty feet. The girl who has shot an apple seed or lemon seed with
pressure of thumb and finger across a small room, can understand the
force needed to shoot a seed but little heavier than that of the apple
two or three times that distance.

[Illustration: FIG. 48.--Dry fruit of witch-hazel shooting seeds.]

CHAPTER VII.
PLANTS THAT ARE CARRIED BY ANIMALS.

With the frosts of autumn ripe acorns, beechnuts, bitternuts,
butternuts, chestnuts, hickory nuts, hazelnuts, and walnuts are
severed from the parent bush or tree and fall to the ground among
the leaves.

37. Squirrels leave nuts in queer places and plant some of them.--Even
before the arrival of frosts many of these are dropped by the aid
of squirrels, gray and red, which cut the stems with their teeth.
The leaves, with the help of the shifting winds, gently cover the
fruit, or some portions of it, and make the best kind of protection
from dry air and severe cold; and they come just in the nick of time.
Dame Nature is generous. She produces an abundance; enough to seed
the earth and enough to feed the squirrels, birds, and some other
animals. The squirrels eat many nuts, but I have seen them carry a
portion for some distance in several directions, and plant one or
two or three in a place, covering them well with soil. It may be the
thought of the squirrel--I cannot read his thoughts--to return at
some future time of need, as he often does. But in some cases he forgets
the locality, or does not return because he has stored up more than
he needs; or in some cases the squirrels leave that locality or are
killed; in any such case the planted nuts are not disturbed. At all
events, some of the nuts--one now and then is all that is needed--are
allowed to remain where planted. In this way the squirrel is a benefit
to the trees and pays for the nuts he eats. He has not lived in vain,
for he is a tree planter and believes in arboriculture. His ar