The North American Species of Crepidotus

Crepidotus malachius var. malachius (B. & C.) Sacc., Syll. Fung. 5: 883. 1887.

Agaricus malachius B. & C., Ann. & Mag. Nat. Hist. Ser. III 4: 291. 1859.

Illustrations: Figs. 91, 92.

Pileus 1-6.5 cm broad, sessile, convex then nearly plane, reniform, semiorbicular, flabelliform, somewhat depressed at base, solitary, gregarious, or imbricate, glabrous, the base often slightly villose or tomentose, hygrophanous, white, watery-white, or grayish-white when wet, pale buff when dried, striatulate when wet. Context white; odor mild, taste fungoid, at times becoming bitterish.

Lamellae rounded at inner extremity, radiating from a basal, lateral point, white, becoming rusty or brownish-ferruginous, crowded or close, broad.

Stipe none; a pseudostipe at times present.

Spores in deposit: "snuff brown" or "Dresden brown," 5-7.5 (8.5) µ, globose, at times subovoid, punctate, brown in 2% KOH. Basidia 25-32 x 6-7 µ, 4-spored. Pleurocystidia none; cheilocystidia 24-52 x 5-10 (12) µ, clavate, ventricose, bottle-shaped, ten-pin-shaped, scattered over the edges and thus absent in many sections. Gill trama subparallel, hyphae 4-9 (10) µ (more rarely 15 µ) broad. Pileus trama interwoven. Cuticle of repent hyphae, rarely with few and scattered erect hyphae. Pileocystidia none. Clamp connections present.

Habit, Habitat, and Distribution: On hardwood logs and stumps, eastern United States, April-September.

Material Studied: MAINE: Bigelow 11145 (MASS); MASSACHUSETTS: Bigelow 7258, 7265 (MASS); MICHIGAN: Shaffer 2591 (MICH); Smith 6237, 33-1003, 37249, 37288, 57246, 57418, 60976, 60978, 66852, 66855, 66874, 67075; THIERS 2703, 2737, 2948, 3196, 3441 (MICH); NEW ENGLAND: Sprague, type (K), August 1856; NEW HAMPSHIRE: Bigelow 11810, 12193; NEW YORK: Deegan 51 (MICH); Murrill (CUP 2658); NORTH CAROLINA: Hesler 8066, 19201; SOUTH CAROLINA: Hesler 24752; TENNESSEE: Hesler 10390, 11438, 12160, 16400,25759,25805.

Observations: The description of microscopic characters above is based chiefly on a study of the type.

The pileus is glabrous, except at times for a villose to tomentose base; sections, therefore, characteristically reveal no pileocystidia and only rarely any erect hyphae. Those collections in which erect, long pileocystidia , 25-45 (83) µ, are present are placed in C. malachius var. trichiferus. Those collections in which a turf is present on the pileus, and the cheilocystidia septate and forked, belong to our C. malachius var. phragmocystidiosus.

Two other variations are mentioned here: in one Smith collection (MICH 16400), some of the pilei are white, others are faintly tinged yellowish; in MICH 67075, the white pileus, on being held over night, became black-spotted, much as in C. maculans. This latter species, however, has pleurocystidia. We hardly regard these as new varieties on the basis of material at hand.