to the lamellae. Even on the gills the purple tinge
of the brown spores can often be seen. The color is more satisfactorily
obtained when the spores are caught in mass by placing the cap, gills
downward, on white paper.

AGARICUS Linn. (PSALLIOTA Fr.)

In the genus _Agaricus_ the spores at maturity are either purple-brown
in mass or blackish with a purple tinge. The annulus is present on the
stem, though disappearing soon in some species, and the stem is easily
separated from the substance of the pileus. The gills are free from the
stem, or only slightly adnexed. The genus is closely related to
_Stropharia_ and the species of the two genera are by some united under
one genus (_Psalliota_, Hennings). Peck, 36th Report, N. Y. State Mus.,
p. 41--49, describes 7 species. Lloyd Mycol. Notes, No. 4, describes 8
species. C. O. Smith, Rhodora, I: 161--164, 1899, describes 8 species.

=Agaricus (Psalliota) campestris= Linn. =Edible.=--This plant has been
quite fully described in the treatment of the parts of the mushroom, and
a recapitulation will be sufficient here. It grows in lawns, pastures,
by roadsides, and even in gardens and cultivated fields. A few specimens
begin to appear in July, it is more plentiful in August, and abundantly
so in September and October. It is 5--8 cm. high (2--3 inches), the cap
is 5--12 cm. broad, and the stem 8--12 mm. in thickness.

The =pileus= is first rounded, then convex and more or less expanded.
The surface at first is nearly smooth, presenting a soft, silky
appearance from numerous loose fibrils. The surface is sometimes more or
less torn into triangular scales, especially as the plants become old.
The color is usually white, but varies more or less to light brown,
especially in the scaly forms, where the scales may be quite prominent
and dark brown in color. Sometimes the color is brownish before the
scales appear. The flesh is white. The =gills= in the young button stage
are white. They soon become pink in color and after the cap is expanded
they quickly become purple brown, dark brown, and nearly black from the
large number of spores on their surfaces. The gills are free from the
stem and rounded behind (near the stem). The =stem= is white, nearly
cylindrical, or it tapers a little toward the lower end. The flesh is
solid, though the central core is less firm. The =veil= is thin, white,
silky, and very frail. It is stretched as the cap expands and finally
torn so that it clings eit