=P. salig´nus= Schwam.—_salix_, willow. =Pileus= 2–3 in. broad, sooty ash-color or ochraceous, fleshy, compact, _spongy_, somewhat dimidiate, _horizontal_, at first pulvinate, even, at length depressed behind and here and there strigose, the incurved margin entire. =Stem= always short, firm, more or less tomentose. =Gills= horizontal, hence less manifestly decurrent, separate behind, but _branched in the middle_, crowded, dingy, often eroded at the edge, not glandular. Among the larger and firmer species. Solitary, scarcely ever cespitose. It is commonly confounded with A. ostreatus, but is certainly a different species. Although the stature is in general the same, it is easily distinguished by the pileus being more compact, and more pulverulent when young, then depressed, by the gills being thinner, more crowded, somewhat branched, but not anastomosing behind, and dingy soot-color; the spores also are dingy. _Stevenson._ =Spores= oblong or cylindrical-oblong, 8×4µ _W.G.S._; 8–10×3–4µ _B._ Dr. Curtis wrote of this: “Indeed I have found several persons who class this among the most palatable species. To such persons a dish of fresh mushrooms need seldom be wanting, as this one can be had every month of the year in this latitude.” In New Jersey, in the vicinity of Philadelphia, Pa., I have found P. salignus in quantity. It has been sent to me by Dr. J.R. Weist, of Richmond, Ind., who writes, “I have eaten it with great enjoyment.” In 1881 I found it frequently on water beeches and willows, and thoroughly tested its edible qualities. _R.K. Macadam_, Boston. When young or fresh, it is quite equal to any Pleurotus. When old, as with others of the Pleuroti, it is tough. Nevertheless their margins are always edible unless decaying. II.—DIMIDIA´TI. =P. petaloi´des= Bull.—petal of a flower. =Pileus= 1–2 in. long, _dingy-brown_, becoming pale, dimidiate, fleshy, but in no wise compact, rather plane, _somewhat spathulate_, continuous with the stem and _depressed behind_, hence the villous down of the stem ascends to this point (the disk) of the pileus, otherwise smooth, even, margin at first involute then expanded. =Stem= about ½ in. long, sometimes however very short, solid, firm, _compressed, channeled_ when larger, more or less villous, whitish. =Gills= _decurrent, very crowded_, very narrow (scarcely beyond 2 mm. broad), linear, very unequal, white then ash-color. Taste bitter. The form on wood is somewhat horizontal, gregarious here and there imbricated. _Stevenson._ =Spores= 9–10×4µ _Massee_; 8×4µ _W.G.S._; minutely globose, 3–4µ _Peck_. Edible. _Cooke_, _Cordier_.