The North American Species of Crepidotus

64. Crepidotus pseudoflammeus sp. nov.

Illustrations: Figs. 131, 132.

Pileus 8-12 mm latus, conchatus demum dimidiatus, fibrillosus, brunneus, fibrillis "xanthine orange," margine fimbriatus; odoris nihil, gustu amarus. Lamellae "pale orange yellow" demum brunneae, confertae, medio-latae. Stipes 2-3 mm longus, "pale orange-yellow," fibrillosus. Sporae 7-9 (10) x 5-6.5 (7) µ, ellipsoideae, planae. Basidia 24-30 x 6-7 µ, tetraspora. Pleurocystidia 23-35 x 5-10 µ; cheilocystidia 35-53 x 5-10 µ. Cuticula ex hyphis repentibus subflavis demum brunnaceis composita, hyphas erectas incrustatas brunneas gerens. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum in Mt. Baker Forest, Wash., Sept. 6, 1941, A. H. Smith 16682.

Pileus 8-12 mm broad, conchate, becoming dimidiate, dry, appressed-fibrillose, fibrils at base "xanthine orange," but "orange" near the pale yellow, incurved, fringed margin, color finally dingy brown. Context thin, pliant, pale yellowish; odor none, taste slightly bitter.

Lamellae bluntly adnate, "pale orange yellow," soon rusty-brown from the spores, moderately close to nearly subdistant and moderately broad, edges crenulate.

Stipe 2-3 mm long, more or less 1 mm thick, curved, "pale orange yellow," densely woolly-fibrillose.

Spores 7-9 (10) x 5-6.5 (7) µ ellipsoid, wall thickened, smooth, no germpore, dark tawny-reddish in 2% KOH. Basidia 24-30 x 6-7 µ, 4-spored. Pleurocystidia 23-35 x 5-10 µ, ventricose, apices rounded; cheilocystidia 35-53 x 5-10 µ, cylindric-capitate, often flexuous. Gill trama subparallel, hyphae 3-6 µ broad. Pileus trama interwoven, hyphae 2-3 µ broad. Cuticle of repent, yellowish to fuscous hyphae, some incrusted; at surface bearing a turf of brownish hyphae, 2-4 µ broad, often in bundles. Clamp connections present.

Habit, Habitat, and Distribution: On Alnus fallen twigs, Washington, September.

Material Studied: WASHINGTON: Smith 16682, type, from Marble Creek, Mt. Baker National Forest, Sept. 6, 1941.

Observations: This is suggestive of Pleuroflammula flammea, which has a veil and lacks pleurocystidia.