The North American Species of Crepidotus

93. Crepidotus variabilis var. trichocystis var. nov.

Illustration: Fig. 165.

Pileus 4-12 mm latus, sessilis, ungulatus, albus, fibrillosus. Lamellae albae demum roseae, denique brunneaceae, confertae velpaene subdistantes, latae. Sporae 4.5-6 x 2.8-4 µ ellipsoideae, punctatae. Basidia 18-25 x 5-6 µ, di- et tetraspora. Pleurocystidia desunt; cheilocystidia 30-55 (82) x 2-5 (6) µ gracilia. Cuticula ex hyphis repentibus composita, hyphas erectas sine colore gerens, 1.5-3 µ latas. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum prope Burt Lake, Mich., July 18, 1963, A. H. Smith 66819.

Pileus 4-12 mm broad, sessile, ungulate, pure white, villose or fibrillose, base cottony-tomentose.

Lamellae white, then pinkish to brownish, close or at times nearly subdistant, broad.

Spores 4.5-6 x 2.8-4.0 µ ellipsoid, slightly to scarcely inequilateral in profile, obscurely punctate. Basidia 18-25 x 5-6 µ, 2-4-spored. Pleurocystidia none; cheilocystidia 30-55 (82) x 2-5 (6) µ, cylindric or filamentous, flexuous, often knobbed, forked, or branched, at times contorted, more rarely coiled. Gill trama subparallel, hyphae 3-5 (9) µ broad. Pileus trama interwoven. Cuticle of repent hyphae, bearing scattered to gregarious, erect hyphae, 1.5-3 µ broad. Clamp connections present.

Habit, Habitat, and Distribution: On hardwood and conifer twigs, branches, and debris, Michigan, Colorado, and Idaho, July-August.

Material Studied: COLORADO: Smith 51448, 51690, 51727, 52376; IDAHO: Smith 58753, 65857; MICHIGAN: Smith 66819, type, on birch twigs, Burt Lake, Maple Bay, July 18, 1963.

Observations: This variety is characterized chiefly by its filamentous to slender cylindric, flexuous or more or less contorted cheilocystidia.