The North American Species of Crepidotus

98. Crepidotus regularis sp. nov.

Illustrations: Figs. 171, 205.

Pileus (5) 10-25 mm latus, sessilis, conchatus deinde flabelliformis, albus, fibrillosus, margine involutus. Lamellae confertae vel subdistantes, latae, albae deinde "cinnamon buff." Sporae 6-8 x 4-5 (5.5) µ, ellipsoideae demum ovoideae, punctatae demum echinulatae. Basidia 25-33 x 6-8 µ tetraspora. Pleurocystidia desunt; cheilocystidia (20) 25-52 x 4-9 (12) µ. Cuticula ex hyphis repentibus composita, apicibus sinuosas vel in spiram volutas. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich., lectum prope Milford, Mich., Aug. 10, 1937, A. H. Smith 6967.

Pileus (5) 10-25 mm broad, sessile, conchate, expanding to flabelliform, opaque, white, white-pubescent or fibrillose, byssoid around the point of attachment, the margin inrolled and often fimbriate. Context thin, white; odor and taste not distinctive (in Smith 51806, taste raphanoid).

Lamellae radiating from a lateral point, or attached to a pseudostipe, close or subdistant, broad, white, becoming cinnamon buff, edges even.

Stipe none, or merely a pseudostipe which soon disappears. Spores 6-8 x 4-5 (5.5) µ, ellipsoid to ovoid, inequilateral in profile, minutely punctate to echinulate, yellowish-brown in 2% KOH. Basidia 25-33 x 6-8 µ, 4-spored. Pleurocystidia none; cheilocystidia (20) 25-52 x 4-9 (12) µ, cylindric, clavate, ventricose, at times more or less forked. Gill trama slightly interwoven, hyphae 3-8 (11) µ, broad. Pileus trama interwoven. Cuticle of repent hyphae, bearing a turf of colorless hyphae, 2-6 µ broad, the tips or upper portions crooked or coiled. Clamp connections present.

Habit, Habitat, and Distribution: On hardwood, rarely on conifer wood, Maine, North Carolina, Michigan, Missouri, Colorado, Idaho, Washington, Oregon, May-October.

Material Studied: COLORADO: Smith 51806, 52939; IDAHO: Smith 65021, Granite Twin Lakes; MAINE: Bigelow 3028 (MICH); MICHIGAN: Beach 11, 25, 26 (MICH); Thiers 2879, 2901, 3069 (MICH); Potter 3465 (MICH); Smith 6967 (type, on hardwood twigs, Milford, Aug. 10, 1937), 21573, 49599, 49681, 49765, 69769, 49770, 49771, 49772, 49773, 49774, 49775, 49803, 49804, 49806, 49807, 49812, 49813, 50999, 57818, 63574, 63578, 66866, 66964, 66990, 67012, 67014, 67206, 67458; MISSOURI: Routien (TENN 13243); NORTH CAROLINA: Hesler 25731; OREGON: Smith 62457; WASHINGTON: Imshaug 1293 (MICH); Smith 13933, 28928.

Observations: In this species, there is an apparent scarcity of striking characters. The pileus is white, the surface hyphae crooked or coiled, the spores medium small, the cheilocystidia regular in form. It is near C. subepibryus, which has straight or only slightly curved, but not coiled, epicuticular hyphae, less variable cheilocystidia, and more conspicuously punctate spores. It is distinguished from C. ellipsoideus and C. lagenicystis by its more regularly shaped cheilocystidia. Although variable, the cheilocystidia are neither contorted nor lageniform. In one collection (MICH 51806), the flesh had a slightly raphanoid taste.