ls white (natural size).
Copyright.]

[Illustration: FIGURE 113.--Pleurotus petaloides. More irregular form
than that shown in figure 112; color same as there described (natural
size). Copyright.]

The =pileus= varies from a regular wedge-shape to spathulate, or more or
less irregularly petaloid, or conchoid forms, the extremes of size and
form being shown in Figs. 112, 113. The margin is at first involute,
finally fully expanded, and the upper surface is nearly plane or
somewhat depressed. The color is often a pale reddish brown, or brown,
and sometimes pure white. The margin is sometimes marked with fine
striations when moist. The upper portion near the union with the stem is
sometimes tomentose, sometimes smooth. The =gills= are narrow, white, or
yellowish, crowded and strongly decurrent. While the plant varies
greatly in form and size, it is easily recognized by the presence of
numerous short whitish =cystidia= in the hymenium, which bristle over
the surface of the hymenium and under a pocket lens present a "fuzzy"
appearance to the lamellae. They are 70--80 x 10--12 mu. The spores are
white.

Figures 112, 113 are from plants collected at Ithaca.

=Pleurotus serotinus= Schrad. This is an interesting plant and occurs
during the autumn on dead trunks, branches, etc., in the woods. The stem
is wanting, and the cap is shelving, dimidiate, reniform or
suborbicular. The plants occur singly or are clustered and overlapping,
about the same size and position as _Claudopus nidulans_, from which it
is readily told by its white gills and spores. The color varies from
dull yellow to brownish, often with shades of olive or green.

=Pleurotus applicatus= Batsch.--This is a pretty little species and
usually occurs on much decayed wood, lying close to the ground so that
it is usually directly on the under side of the log or branch. It does
occur, however, on the side of the log when it is more or less shelving,
because of the tendency of the pileus always to be more or less
horizontal.

[Illustration: FIGURE 114.--Pleurotus applicatus. Color gray to dark
bluish gray, or black with a bluish tinge (natural size). Copyright.]

The =pileus= is 4--6 mm. broad, its upper surface closely applied to the
wood or bark on which it is growing when it appears directly on the
under side. The margin is sometimes free and involute. Sometimes it is
attached only by the center of the pileus. There is then often a short
process. When it grow