universal veil, that is, a layer of fungus tissue which
entirely envelops the young plant. In the button stage, where this
envelope runs over the cap, it is more or less free from it, that is, it
is not "concrete" with the surface of the pileus. As the pileus expands
and the stem elongates, the volva is ruptured in different ways
according to the species. In some the volva splits at the apex and is
left as a "cup" at the base of the stem. In others it splits circularly,
that is, transversely across the middle, the lower half forming a
shallow cup with a very narrow rim, or in other cases it is closely
fitted against the stem, while the upper half remains on the cap and is
broken up into patches or warts. In still other cases the volva breaks
irregularly, and only remnants of it may be found on either the base of
the stem or on the pileus. For the various conditions one must consult
the descriptions of the species. The genus is closely related to
_Lepiota_, from which it is separated by the volva being separate from
the pileus. This genus contains some of the most deadly poisonous
mushrooms, and also some of the species are edible. Morgan, Jour. Mycol.
=3=: 25--33, describes 28 species. Peck, 33d Report N. Y. State Mus.,
pp. 38--49, describes 14 species. Lloyd, A Compilation of the Volvae of
the U. S., Cincinnati, 1898, gives a brief synopsis of our species.

=Amanita muscaria= Linn. =Poisonous.=--This plant in some places is
popularly known as the fly agaric, since infusions of it are used as a
fly poison. It occurs during the summer and early autumn. It grows along
roadsides near trees, or in groves, and in woods, according to some
preferring a rather poor gravelly soil. It attains its typical form
usually under these conditions in groves or rather open woods where the
soil is poor. It is a handsome and striking plant because of the usually
brilliant coloring of the cap in contrast with the white stems and
gills, and the usually white scales on the surface. It usually ranges
from 10--15 cm. high, and the cap from 8--12 cm. broad, while the stem
is 1--1.5 cm. in thickness, or the plant may be considerably larger.

[Illustration: PLATE 12, FIGURE 52.--Amanita muscaria, "buttons,"
showing different stages of rupture of the volva or universal veil, and
formation of inner veil (natural size). Copyright.]

[Illustration: PLATE 13, FIGURE 53.--Amanita muscaria. Further stages in
opening of plant, formation of veil and ring.