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.
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.
HYGROPHORUS Fries.
Figure 115.—Hygrophorus chrysodon. Entirely white with golden yellow granules on cap and stem (natural size). Copyright.
The genus Hygrophorus is one which presents some difficulties in the case of some of the species, especially to beginners, and plants need to be studied in the fresh condition to understand the most important character which separates it from certain of the other white-spored agarics. The substance of the pileus is continuous with that of the stem, that is, the stem is not easily separated from the cap at the point of junction, but is more or less tenacious. The gills may be adnexed, adnate, sinuate, or decurrent, but what is important they are usually rather distant, the edge is acute or sharp, and gradually thickened toward the junction with the cap, so that a section of the gill is more or less triangular. This is brought about by the fact that the substance of the cap extends downward into the gill between the laminæ or surfaces of the gill. But the most important character for determining the genus is the fact that the surfaces of the gills become rather of a waxy consistency at maturity, so that they appear to be full of a watery substance though they do not bleed, and the surface of the gill can be rather easily removed, leaving the projecting line of the trama. This is more marked in some species than in others. The waxy consistency of the gills then, with the gills acute at the edge, broad at the point of attachment to the pileus, and the gills being rather widely separated are the important characters in determining the species which belong to this genus. The nearest related genus is Cantharellus, which, however, has blunt and forked gills. A number of the plants are brilliantly colored.