The North American Species of Crepidotus

26. Crepidotus tahquamenonensis sp. nov.

Illustration: Fig. 76.

Pileus 8-25 mm latus, sessilis, flabelliformis demum reniformis, albus deinde obscurus, glabrosus. Lamellae latae, confertae, albae deinde sub-brunneae. Sporae 4.5 -5.5 µ, globosae, punctatae. Basidia 16-20 x 6-7 µ, tetraspora. Pleurocystidia desunt; cheilocystidia 28-42 x 5-13 µ. Cuticula ex hyphis repentibus composita, hyphas erectas et pileocystidia gerens. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum in Tahquamenon Falls State Park, Mich., Aug. 9, 1956, Thiers 3907.

Pileus 8-25 mm broad, sessile, flabelliform to reniform, white, becoming dingy in age, glabrous, at times tomentose on the disk or at the base. Context white; odor and taste mild.

Lamellae broad, close, thin, white becoming brownish. Spores 4.5-5.5 µ in diameter, globose, punctate.

Basidia 16-20 x 6 -7 µ, 4-spored. Pleurocystidia none; cheilocystidia 28-42 x 5-13 µ, clavate and often capitate or forked, or ventricose. Gill trama subparallel to slightly interwoven, hyphae 5-8 µ broad. Pileus trama interwoven. Cuticle of repent hyphae, bearing scattered, erect hyphae, at times as cylindric pileocystidia. Clamp connections present.

Habit, Habitat, and Distribution: On hardwood log, Michigan, August.

Material Studied: MICHIGAN: Thiers 3907 (MICH), type, from Tahquamenon Falls State Park, Aug. 9, 1956.

Observations: This is distinguished from C. conchatus by its much larger, flabelliform to reniform pileus, and different cheilocystidia.