The North American Species of Crepidotus

70. Crepidotus payettensis sp. nov.

Illustration: Fig. 143.

Pileus 5-12 mm latus, sessilis, dimidiatus, glabrosus, paene "buckthorn brown" deinde fusco-ochraceus. Lamellae confertae, latae, obscuro-fulvae. Sporae (5.5) 6.5-8.5 x 4.5-5.5 (6) µ, ellipsoideae, punctatae. Basidia 23-30 x 6-8 µ, tetraspora. Pleurocystidia desunt; cheilocystidia 26-44 x 5-10 µ. Cuticula ex hyphis repentibus composita, hyphas erectas sine colore gerens. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum in Payette National Forest, Idaho, July 14, 1958, A. H. Smith 58531.

Pileus 5-12 mm broad, sessile, dimidiate, glabrous and smooth to the place of insertion on substratum, near "buckthorn brown," moist, (dingy yellow brown), fading to dingy ochraceous, margin even and naked, surface becoming somewhat rivulose. Context thin, pliant, dingy pallid; odor and taste none.

Lamellae close, broad, attached to a basal point, at maturity dingy fulvous, between "ochraceous tawny" and "buckthorn brown," edges even or uneven.

Spores (5.5) 6.5-8.5 x 4.5-5.5 (6) µ, ellipsoid, minutely punctate, wall double, brown in 2% KOH. Basidia 23-30 x 6-8 µ, 4-spored. Pleurocystidia none cheilocystidia 26-44 x 5-10 µ, clavate, or cylindrical, at times somewhat ventricose, at times capitate, sometimes constricted. Gill trama interwoven, hyphae 4-8 µ broad. Pileus trama densely interwoven. Cuticle of repent hyphae, bearing scattered, more or less erect, colorless hyphae. Clamp connections present but rare.

Habit, Habitat, and Distribution: On decorticated lodgepole pine log, Idaho, July.

Material Studied: IDAHO: Smith 58531, type, from South Fork, Lake Fork Creek, Payette National Forest, July 14, 1958.

Observations: This species is related to C. kauffmanii, but is distinguished by its glabrous, differently-colored pileus and lack of brown, incrusted, epicuticular hyphae.