The North American Species of Crepidotus

67. Crepidotus fragilis Joss., Bull. Soc. Myc. France 53: 218. 1937.

Illustrations: Figs. 137, 138.

Pileus 2-7 cm broad, sessile, of variable form: either flattened and pleuropodic, or convex, slightly hygrophanous, gray, clay, or even fuliginous when wet, snow white when dry, grooved fibrillose giving the effect of rimosity which gives the pileus snow white and clayish-gray streaks, margin sinuous, scalloped, or lobed. Context very thin on the margin, thick near base, fragile, white when dry, dark-gray when wet, not gelatinous; odor and taste fungoid.

Lamellae rather narrow, thin, rounded at point of attachment, almost white, then very pale clay color, finally deep clay to dark earthy color. Spores in deposit: deep clay color, earthy (olive tinged).

Spores 7-9 (10) x 4.5-5.8 µ, amygdaliform (tonsil shaped), smooth. Basidia 25-33 x 7-8 µ, 4-spored. Pleurocystidia 28-40 x 5-8 µ, clavate-appendiculate, at times numerous; cheilocystidia 25-40 x 6-10 µ, more or less cylindric, slightly sinuous, obtuse, not capitate. Gill trama with a broad mediostrate composed of filamentous hyphae, 4-10 (20) µ broad, undulating-parallel. Subhymenium subcellular. Pileus trama interwoven, hyphae 6-20 µ broad. Cuticle of repent hyphae bearing a turf of colorless hyphae, 3-10 µ broad. No gelatinous zone. Clamp connections present.

Habit, Habitat, and Distribution: On soil or decaying wood, France, September.

Material Studied: FRANCE: from Doubs, collected and determined by C. Bas, Oct. 3, 1956 (L).

Observations: The description of macroscopic characters above is based on Josserand's account (1937); that of the microscopic characters is based largely on a collection from France, by Bas, Leiden, Netherlands, and deposited as Tenn-26099. Although Josserand does not mention pleurocystidia, they were found in Bas' material. Pilát (1948) reports this species from Czechoslovakia and Germany. It has not been reported from North America but is included here for comparison, and on the possibility that it might be discovered here.