urface, since the fruiting surface is smooth, especially when
the plants are young or middle age. However, when the plants get quite
large and old, in some cases the fruiting surface becomes very uneven
from numerous folds and wrinkles, which, however, are more irregular
than the folds of _C. cibarius_.

=Craterellus cornucopioides= (L.) Pers., is another edible species. It
grows on the ground in woods. It is of a dusky or dark smoky color, and
is deeply funnel-shaped, resembling a "horn of plenty," though usually
straight. The fruiting surface is somewhat uneven.

The genus _Stereum_ is a very common one on branches, etc., either
entirely spread out on the wood, or with the margin or a large part of
the pileus free. _Hymenochaete_ is like _Stereum_, but has numerous small
black spines in the fruiting surface, giving it a velvety appearance.
_Corticium_ is very thin and spread over the wood in patches.

[Illustration: PLATE 81, FIGURE 209.--Lycoperdon cyathiforme (natural
size).]

CHAPTER XIV.

PUFF-BALLS: LYCOPERDACEAE.

This is not the place for a discussion of the different genera of the
puff-balls, etc., but it might be well to say that in recent years the
old genus _Lycoperdon_ has been divided into several genera. The giant
puff-ball, and the _L. cyathiforme_, where the wall or peridium ruptures
irregularly, have been placed in a genus called _Calvatia_; certain
other species which are nearly globose, and in which the wall is of a
papery texture at maturity, are placed in the genus _Bovista_. There is
one genus belonging to the same family as the lycoperdons, the species
of which are very interesting on account of the peculiar way in which
the wall is ruptured. This is the genus _Geaster_, that is, "earth
star." The wall, or peridium, is quite thick in the members of this
genus, and when it matures it separates into several layers which need
not all be discussed here. A thick outer portion which separates from a
thinner inner portion further splits radially into several star-like
divisions, which spread outward and give to the plant the form of a
star. Since the plants lie on the earth the name earth star was applied
to them. This opens out in dry weather, even curving around under the
plant, so that the plant is raised above the ground. Then in wet weather
it closes up again. The inner portion of the wall opens at the apex in
various ways, in the different species, so that the spores may escape. A