ly more vigorous and healthy than others; and it
is probably to accidental crosses we are indebted for many varieties
that differ so widely from their parents. A cross is most apparent to
the eye when the parents are of different colors, in which case the
offspring will be striped or marked with the colors of each parent.

HOW TO CROSS VARIETIES.

In order to comprehend fully the principles of this subject, and their
application to practical operations, it will be necessary to take a
general view of the generative organs of the vegetable kingdom, and the
manner in which they act in the production of their species. If we
examine a perfect flower, we shall find that it consists essentially of
two sets of organs, one called the pistils, the other the stamens. The
pistils are located in the centre of the flower, and the stamens around
them. The summit of the pistil is called the stigma; and on the top of
each stamen is situated an anther--a small sack, which contains the
pollen, a dust-like substance, that fertilizes the ovules or young seeds
of the plant.

These organs are supposed to perform offices analogous to those of the
animal kingdom--the stamens representing the male, and the pistils the
female organs.

When the anthers, which contain the pollen, arrive at maturity, they
open and emit a multitude of minute grains of pollen; and these, falling
on the pistils of the flower, throw out hair-like tubes, which penetrate
through the vascular tissue of the pistil, and ultimately reach the
ovules, thus fertilizing them, and making them capable, when mature, of
reproducing plants of their own kind.

The ovules are the rudimentary seeds, situated in a case at the base of
the pistils, each consisting of a central portion, called the nucleus,
which is surrounded by two coats, the inner called the secundine, the
outer the primine. When the hairlike tube of the pollen-grain passes
through the orifice in the coatings of the ovule, and reaches the
nucleus, or embryo sack, it is supposed to emit a spermatic or plantlet
germ, which passes through the wall of the embryo sack and enters the
germinal vesicle contained in it. The vesicle corresponds to the
vesicle, or germinal spot, in the eggs of birds, and ovum of mammiferous
animals. The germ remains in the vesicle, and finally becomes the
embryo, fully developed into a plantlet, as may be seen in many seeds.

Flowers of plants are called perfect when the stamens and pistils a