=C. rivulo´sa= Pers.—_rivus_, a stream. (Named from rivulet-like streaks on pileus.) =Pileus= 1–3 in. across, flesh thin, convex then plane and depressed, obtuse, often undulately lobed, dingy flesh-color or reddish, becoming pale, glabrous, then covered with a whitish down. =Gills= slightly decurrent, broad, rather crowded, pinkish-white. =Stem= about 2 in. long, 3–4 lines thick, rather fibrillose, tough, elastic, whitish, stuffed. =Spores= elliptical, 6×3.5µ. _Massee._ Among grass by road-sides, etc. Not common, but when found it is basket-filling. I have found it in Pennsylvania, New Jersey and West Virginia. Edible. The caps are rather tough but become glutinous and tender when well cooked. Flavor fine. ***** _Pileus white, shining when dry._ =C. cerussa´ta= Fr.—_cerussa_, white lead. =Pileus= 1½-3 in. across, flesh thick at the disk, becoming thin toward the margin; convex then almost plane, obtuse, even, minutely floccose then almost glabrous, white. =Gills= adnate, then decurrent, very much crowded, thin, permanently white. =Stem= about 2 in. long, 3–5 lines thick, smooth, tough, elastic, naked, spongy and solid, white. Among dead leaves, etc. Taste mild, smell almost obsolete. Stem rather thickened at the base and often tomentose. Pileus said to be gibbous, but not umbonate nor becoming rufescent. Gills not changing to yellowish. _Fries._ =Spores= 3µ _W.G.S._ Edible. Good. =C. phylloph´ila= Fr. _Gr._—leaf-loving. Whitish-tan. =Pileus= 1–3 in. across, rather fleshy, convex then plane, becoming umbilicate and depressed, sometimes wavy, smooth and even. =Gills= thin, subdistant, white then tinged with ocher, rather broad, very slightly decurrent. =Stem= 2–3 in. long, equal, stuffed then hollow, whitish, tough, silky-fibrillose. =Spores= 6×4µ. Among leaves in woods, etc. =Spores= 6×4µ _Massee_; 6×3µ _W.G.S._; 5.5×2.8µ _Morgan_. Found at Devon, Pa., 1888; Angora, West Philadelphia, 1897. It is equal to the Pleurotus ostreatus (oyster mushroom) in texture, but not so high in flavor. Well cooked it is an agreeable and valuable food. =C. pithyoph´ila= Secr. _Gr._—pine-loving. =Pileus= 2–3 in. broad, dead-white when moist, shining whitish when dry, fleshy but _thin_, rather plane, _umbilicate_, at length irregularly shaped, repand and undulato-lobed, even, _smooth, flaccid_, the margin slightly striate when old. =Stem= _somewhat hollow_, rounded then compressed, equal, even, smooth, obsoletely or scarcely pruinose at the apex, white tomentose at the (not bulbous) base. =Gills= adnate, somewhat decurrent, _very crowded_, plane, 2–3 lines broad, distinct, quite entire, white. Odor not remarkable, but pleasant. Gregarious, somewhat cespitose; _white_ indeed, but when moist watery and _somewhat hygrophanous_, in which it evidently differs from A. phyllophila. A. tuba, which appears in the same places, is very like it. _Stevenson._ =Spores= 6–7×4µ _B._ Massachusetts, _Sprague_; New York, _Peck_, Bull. 1887.