The North American Species of Crepidotus

116. Crepidotus subverrucisporus var. megalosporus var. nov.

Illustrations: Figs. 31, 190.

Pileus 5-15 (20) mm latus, sessilis, ungulatus, dimidiatus, albus deinde obscuro "vinaceous buff," albo-fibrillosus, margine involutus. Lamellae albae deinde roseae denique brunnaceae, medio-latae, confertae vel paene subdistantes. Sporae 8-13 x 5-7 µ, ellipsoideae demum ovoideae vel graniformes, rugosae. Basidia 28-34 x 6-8 µ, tetraspora. Pleurocystidia desunt; cheilocystidia 38-76 x 4-10 µ. Cuticula ex hyphis repentibus composita, hyphas erectas gerens, 3-6 µ latas. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum prope Ophir, Colo., Aug. 1, 1956, A. H. Smith 51582.

Pileus 5-15 (20) mm broad, sessile, ungulate, dimidiate, white, in age dingy vinaceous buff, white fibrillose, cottony toward the base, white-mycelioid at the point of attachment, margin inrolled.

Lamellae at first white, then becoming pinkish, finally rusty brown, medium broad, close or nearly subdistant, edges at times fimbriate.

Spores 8-13 x 5-7 µ, ellipsoid to ovoid, at times pip-shaped, more or less inequilateral in profile, wrinkled. Basidia 28-34 x 6-8 µ, 4-spored. Pleurocystidia none; cheilocystidia 35-76 x 4-10 µ, cylindric, clavate, flask-shaped or obclavate, often with a strangulate neck. Gill trama interwoven, hyphae 4-7 µ broad. Pileus trama interwoven. Cuticle of repent hyphae, bearing a turf of hyphae which are often arranged in palisade, 3-6 µ broad. Clamp connections present.

Habit, Habitat, and Distribution: On hardwood (Alnus and Populus), Colorado, July-August.

Material Studied: COLORADO: Smith 51540, 51582 (type, from Ophir, Aug. 1, 1956), 51947, 52229, 52375, 52852.

Observations: This differs from the type species in its pinkish gills, palisade-like turf on the cuticle, and larger spores. The cheilocystidia are quite similar to those of the type variety. The pinkish gills suggest a relationship to C. epibryus, which, however, has smaller spores and different cheilocystidia.