The North American Species of Crepidotus

118. Crepidotus helicus sp. nov.

Illustration: Fig. 193.

Pileus 3-7 mm latus, convexus deinde flabelliformis, fibrillosus, flavidus deinde obscuro "pinkish buff." Lamellae latae, confertae demum subdistantes, marginibus  crenulatae. Sporae 7.5-10 x 4.5-5.5 µ, ovoideae vel ellipsoideae, punctatae. Basidia 22-27 x 5-6 µ, tetraspora. Pleurocystidia desunt; cheilocystidia 31-63 x 4-9 µ. Cuticula ex hyphis repentibus composita, hyphas erectas, sinuosas et in spiram volutas, sine colore gerens. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum in Cheboygan County, Mich., Aug. 7, 1946, A. H. Smith 22054.

Pileus 3-7 mm broad, convex, becoming flabelliform, or, when on the lower side of the substratum, reniform, fibrillose, yellowish, drying dull pinkish buff.

Lamellae radiating, broad, close to subdistant, cinnamon buff when dried, edges crenulate.

Stipe none, or present as a pseudostipe.

Spores 7.5-10 x 4.5-5.5 µ, ovoid to ellipsoid, inequilateral in profile, punctate, near cinnamon buff in 2% KOH. Basidia 22-27 x 5-6 µ, 4 -spored. Pleurocystidia none; cheilocystidia 31-63 x 4-9 µ, cylindric, ventricose, at times clavate, with or without a neck. Gill trama subparallel, hyphae 4-6 µ broad. Pileus trama interwoven. Cuticle of repent hyphae, bearing a turf of colorless hyphae, the apical portion more or less crooked and coiled. Clamp connections present.

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

Material Studied: MICHIGAN: Smith 22054, type, from Wolf's Bog, Cheboygan County, Aug. 7, 1946.

Observations: This species is related to C. circinatus, but is distinguished by its larger spores.