nd
higher cryptogams.

To take the example of moss spores:

Certain cells in the sporogonium of a moss are called mother-cells. The
protoplasm of each one of these becomes divided into four parts. Each of
these parts then secretes a cell-wall and becomes free as a spore by the
rupture or absorption of the wall of the mother-cell. The germination of
the spores I shall describe later.

5. A process of budding which in the yeast plant and in mosses is merely
vegetatively reproductive, in fungi becomes truly reproductive, namely,
the buds are special cells arising from other special cells of the
hyphae.

For example, the so-called "gills" of the common mushroom have their
surface composed of the ends of the threads of cells constituting the
hyphae. Some of these terminal cells push out a little finger of
protoplasm, which swells, thickens its wall, and becomes detached from
the mother-cell as a spore, here called specially a _basidiospore_.

Also in the common gray mould of infusions and preserves, Penicillium,
by a process which is perhaps intermediate between budding and
cell-division, a cell at the end of a hypha constricts itself in several
places, and the constricted portions become separate as _conidiospores_.

_Teleutospores, uredospores_, etc., are other names for spores similarly
formed.

These conidiospores sometimes at once develop hyphae, and sometimes, as
in the case of the potato fungus, they turn out their contents as a
swarm-spore, which actively moves about and penetrates the potato leaves
through the stomata before they come to rest and elongate into the
hyphal form.

So far for asexual methods of reproduction.

I shall now consider the sexual methods.

The distinctive character of these methods is that the cell from which
the new individual is derived is incapable of producing by division or
otherwise that new individual without the aid of the protoplasm of
another cell.

Why this should be we do not know; all that we can do is to guess that
there is some physical or chemical want which is only supplied through
the union of the two protoplasmic masses. The process is of benefit to
the species to which the individuals belong, since it gives it a greater
vigor and adaptability to varying conditions, for the separate
peculiarities of two individuals due to climatic or other conditions are
in the new generation combined in one individual.

The simplest of the sexual processes is conjugation. H