The North American Species of Crepidotus

23. Crepidotus maculans sp. nov.

Illustrations: Figs. 3, 70, 71.

Pileus 2-6 cm latus, sessilis, flabelliformis, hygrophanus, colore lacteus demum niveus, denique atras maculas exponens. Lamellae latae, confertae vel subdistantes, albae demum "Sayal brown." Sporae 5.5-7 µ globosae, punctatae. Basidia 25-33 x 7-10 µ, tetraspora. Pleurocystidia 27-40 x 6-8 µ; cheilocystidia 26-42 x 5-10 µ. Cuticula ex hyphis repentibus composita. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum prope Emerson, Michigan, Aug. 12, 1963, A. H. Smith 67118.

Pileus 2-6 cm broad, sessile, fan-shaped, glabrous, moist, hygrophanous, milk-white when young, fading to snow-white, in age developing blackish spots, margin translucent striate at maturity (moist). Context thin, only moderately fragile; odor and taste not distinctive. Lamellae broad, subdistant varying to close, attached to a white basal point, white becoming dull cinnamon ("Sayal brown") thin, edges even. Spores 5.5-7 µ, globose, punctate. Basidia 25-33 x 7-10 µ, 4-spored. Pleurocystidia 27-40 x 6-8 µ, more or less ventricose, at times with a tapering neck, not projecting far, scattered, not conspicuous; cheilocystidia 26-42 x 5-10 µ, clavate-basidioid, ventricose, or more rarely slightly contorted. Gill trama more or less interwoven, hyphae 3-6 µ broad. Pileus trama interwoven. Cuticle of repent hyphae. Clamp connections present.

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

Material Studied: MICHIGAN: Smith 67118 (type, from Emerson, Aug. 12, 1963), 67121, 67122, 67123, 67124, 67125, 67126, 67129, 67130, 67131.

Observations: The pilei average larger than in most species of Crepidotus. The milk-white pileus, which develops blackish spots in age, its pleurocystidia, and very broad gills distinguish it.