The North American Species of Crepidotus

27. Crepidotus harperi Sing., Mycologia 51: 586. 1959.

Illustrations: Singer, Mycologia 51, figs. 1-2, and 17. Fig. 77.

Pileus 7-19 mm broad, convex then repand, white, tomentose, broadly attached behind on vertical surfaces, pendulous-applicate on the lower side on horizontal surfaces. Context white, thin.

Lamellae rounded-concurrent behind, whitish then brown, narrow to medium broad (rarely more than 0.1 of pileus diameter in breadth), close.

Stipe rudimentary, extremely small and disappearing at maturity, functionless, with a white, tomentose base.

Spores 4.3-5.3 x 4-5 µ, globose to subglobose, echinulate, brown, wall moderately thick. Basidia 17-20 x 5-5.5 µ, 2-4-spored. Pleurocystidia none; cheilocystidia 18-35 x 4-8 µ, versiform: cylindric-subcapitate, clavate, apices obtuse or more rarely appendiculate, occasionally irregularly ventricose-capitate, at times slightly nodulose. Gill trama undulating-subparallel, hyphae 3-7 µ broad. Pileus trama of slightly interwoven hyphae. Cuticle of repent hyphae bearing a dense trichodermial zone of loosely tangled, colorless hyphae, 3-5 µ broad. Clamps present.

Habit, Habitat, and Distribution: On wood, densely gregarious, Virginia, May.

Material Studied: VIRGINIA: Harper 1177, type (F), May, 1919.

Observations: The description of microscopic characters above is based on a study of the type. The tomentose pileus and the small spores characterize this species.