The North American Species of Crepidotus

74. Crepidotus hamulatus sp. nov.

Illustration: Fig. 147.

Pileus 3-6 mm latus,flabelliformis demum semiorbicularis, pallido-avellaneus, villosus. Lamellae pallidae deinde brunnaceae, subdistantes demum paene confertae, latae vel medioilatae. Sporae 7.5-11 x 4.5-6 (7) µ ellipsoidae, punctatae. Basidia 24-31 x 6-7 µ, di- et tetraspora. Pleurocystidia desunt; cheilocystidia 32-50 x 5-7 µ. Cuticula ex hyphis repentibus composita, hyphas erectas sine colore gerens, illas marginibus sinuosas et in spiram volutas. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum in Cheboygan County, Mich., Aug. 14, 1957, A. H. Smith 66271.

Pileus 3-6 mm broad, flabelliform to semiorbicular, pallid avellaneous, minutely villose under a lens, especially on the margin.

Lamellae pallid then brownish, broad or medium broad, subdistant to nearly close, edges fimbriate.

Spores 7.5-11 x 4.5-6 (7) µ, ellipsoid, inequilateral in profile, punctate. Basidia 24-31 x 6-7 µ, 2-4-spored. Pleurocystidia none; cheilocystidia 32 -50 x 3-7 µ, filamentous, slender-ventricose, clavate, apices often tapering upward. Gill trama slightly interwoven, hyphae 3-7 µ broad. Pileus trama densely interwoven, appearing more or less cellular in tangential sections. Cuticle of repent hyphae, the surface bearing scattered, colorless, straight, erect hyphae, 15-30 x 2-3 µ; the margin with dense, crooked and coiled hyphae, 3-4 µ broad. Clamp connections present.

Habit, Habitat, and Distribution: On Acer, Michigan, August.

Material Studied: MICHIGAN: Smith 66271, type, from Mud Lake Bog, Cheboygan County, Aug. 14, 1957.

Observations: This species is close to C. kauffmanii, which has colored, incrusted fibrils on the pileus and distinctly smaller spores.