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 lamellæ. They are 70--80 × 10--12 µ. 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 grows on the side of the log it is attached laterally, or on the upper side of one margin, while the greater portion of the pileus is free and shelving. The surface is smooth or somewhat hairy. The color varies from gray to dark bluish gray, or black with a bluish tinge. The =gills= are thick, broad in proportion to the size of the cap, distant, and are said by some to be paler than the pileus. In plants collected at Ithaca, the gills are often as dark as the pileus. The entire plant is rather tough, and revives after being dried if placed in water, resembling in this respect _Marasmius_, _Panus_, or _Trogia_, and it may be more nearly related to one of these. Figure 114 is from plants (No. 4599, C. U. herbarium) collected at Ithaca.