The North American Species of Crepidotus

24. Crepidotus cystidiosus sp. nov.

Illustrations: Figs. 4, 72, 73.

Pileus 1.5-6 cm latus, sessilis, albus demum pallidus, hygrophanus, deinde alutaceus vel coriaceus, glabrosus vel tomentosus. Odore mitis, gustu mox amarus vel stypticus. Lamellae confertae, medio-latae demum latae, albae, deinde obscuro-"clay color." Sporae 5-7.5 µ, globosae, punctatae. Basidia 24-36 x (6) 7-9 (12) µ, di- et tetraspora. Pleurocystidia (24)35-62 x 5-12 µ; cheilocystidia 24-48 (55) x 5-11 µ. Cuticula ex hyphis repentibus composita. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum prope Colonial Point Hardwoods, Michigan, July 22, 1963, A. H. Smith 66854.

Pileus 1.5-6 cm broad, sessile, white or pallid, hygrophanous, becoming alutaceous to buff in age, spathulate, dimidiate, or reniform, glabrous, or slightly tomentose, margin striate when moist. Context thin, white, soft; odor mild, taste fungoid or mild, soon becoming somewhat bitter-astringent.

Lamellae close, medium broad to broad, white, becoming dull clay color, edges fimbriate.

Spores 5-7.5 µ in diameter, globose, punctate, "Sayal brown" to cinnamon brown in deposit. Basidia 24-36 x (6) 7-9 (12) µ, 2-4-spored (rarely 1-spored). Pleurocystidia (24) 35-62 x 5-12 µ, versiform: clavate, at times mucronate or appendiculate, or ventricose, more rarely capitate; cheilocystidia 24-48 (55) x 5-11 µ, clavate to ventricose. Gill trama subparallel to interwoven, hyphae 5-9 (17) µ broad. Pileus trama loosely interwoven. Cuticle of repent hyphae, at times poorly differentiated, with or without pileocystidia . Clamp connections present.

Habit, Habitat, and Distribution: On logs of hardwood. Maine, Massachusetts, Michigan, New York, North Carolina, and Tennessee, June-October.

Material Studied: MAINE: Bigelow 10570 (MASS); MASSACHUSETTS: Bigelow 6824, 6825 (MASS); MICHIGAN: Beach 32 (MICH); Smith 33-1003, 41605, 61026, 66278, 66851, 66853, 66854 (type, from Colonial Point Hardwoods, July 22, 1963), 66856, 67073; Thiers 2668, 2785, 3362 (MICH); NEW YORK: Deegan 81 (MICH); NORTH CAROLINA: Hesler 4331, 5116, 19157, 25528; TENNESSEE: Hesler 24946, 25811.

Observations: This resembles C. malachius var. malachius from which it is distinguished by the pleurocystidia.