The North American Species of Crepidotus
17. Crepidotus herbarum (Pk.) Sacc., Syll. Fung. 5: 888. 1887.
Agaricus herbarum Pk., Buffalo Soc. Nat. Sci. Bull. 1: 53. 1873.
Pleurotellus herbarum (Pk.) Sing., Lilloa 13: 84. 1947.
Illustrations: Figs. 58, 59.
Pileus 8-22 mm broad, white, villose or tomentose, glabrescent, sessile, reniform, suborbicular, or dimidiate, margin incurved. Context medium thin, white.
Lamellae radiating from a lateral or eccentric point, subdistant, medium broad, white when young, finally pale ochraceous.
Stipe none; pileus strongly villose at point of attachment.
Spores 6-8 x 2.8-3.6 µ, pip-shaped, sublanceolate to somewhat ellipsoid to subovoid, smooth, colorless to pale yellow in 2% KOH. Pleurocystidia none; cheilocystidia 22-51 x 4-7 µ, clavate, cylindric, or ventricose, more rarely forked, clustered and conspicuous. Gill trama undulating subparallel, or at times slightly interwoven. Pileus trama interwoven, hyphae 3-4 µ, broad. Cuticle a trichodermium, the epicuticular hyphae loosely tangled, colorless, more or less erect, slender (2-4 µ broad). Clamp connections none (except on the hyphae at the point of attachment of pileus).
Habit, Habitat, and Distribution: On deciduous logs and twigs, and herbaceous stems, general in temperate North America, June-November.
Material Studied: MASSACHUSETTS: Bigelow 6265; MICHIGAN: Smith 57414; NEW YORK: Peck, type (NYS) from North Green bush, on herbaceous stems; OHIO: Cooke 33952 (MICH); OREGON: Smith 20222, 55544; TENNESSEE: Hesler and Rice 3656.
Observations: The spores of C. herbarum are unique in the genus. They are pip-shaped to lanceolate, and pale brownish yellow in mass. Because of its pale spores, Singer (1947, 1962) places C. herbarum in the genus Pleurotellus, and lists it, and some others, as synonyms of P. hypnophilus. In the collections examined, all characters seemed constant except that in one of the Oregon collections (MICH 20222) the cheilocystidia are filamentous, 2-4 µ broad.