The North American Species of Crepidotus
122. Crepidotus fimbriatus sp. nov.
Pileus 8-30 mm latus, conchatus demum dimidiatus, fibrillosus, obscuro-"clay color." Lamellae albae deinde obscuro-pallido-ochraceae demum flavido-brunneae, medio-confertae, latae vel medio-latae. Sporae (5) 6-8 x 4.3-5.5 µ, ovoideae demum ellipsoideae, punctatae. Basidia 27-35 x 6.5-8 µ, di- et tetraspora. Pleurocystidia desunt; cheilocystidia (17) 27-54 x 5-9 µ. Cuticula sine magno discrimine, hyphas erectas gerens, 2-3 µ latas. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum in Payette National Forest, Idaho, June 29, 1958, R. Gilbertson, Smith 58396.
Pileus 8-30 mm broad, conchate to dimidiate, densely and loosely fibrillose, margin glabrescent and then exposing the dingy clay-colored ground color. Context pliant; odor none, taste mild.
Lamellae white at first, soon dingy pale ochraceous, then pale yellow-brown, medium close to subdistant, broad or medium broad.
Stipe none, or only a slight pseudostipe.
Spores (5) 6-8 x 4.3-5.5 µ, ovoid to ellipsoid in face view, slightly inequilateral in profile, punctate, brownish in 2% KOH. Basidia 27-35 x 6.5-8 µ, 2-4-spored. Pleurocystidia none; cheilocystidia (17) 27-54 x 5-9 (12) µ, ventricose, cylindric-constricted, at times flexuous, rarely forked, apices rounded, or subcapitate, at times knobbed. Gill trama subparallel, hyphae 4-10 µ broad. Pileus trama interwoven. Cuticle slightly differentiated, bearing a turf of hyphae, 2-3 µ broad. Clamp connections present.
Habit, Habitat, and Distribution: On hardwood and conifers, Michigan, Colorado, and Idaho, June-July.
Material Studied: IDAHO: Smith 58396, type, from Payette National Forest, on fallen fir branch, in a snow bank, leg. R. Gilbertson, June 29, 1958; MICHIGAN: Smith 66384; WYOMING: Smith 34451, 34452.
Observations: This species is characterized by its yellowish-brown, or yellowish-clay pileus, which has an incurved, fimbriate margin. It differs from C. pallidoluteus, in which the pileus is more yellowish and non-fimbriate.