The North American Species of Crepidotus

96. Crepidotus sphaerosporus (Pat.) Lange, Dansk Bot. Arkiv. 9: 52. 1938.

Agaricus variabilis var. sphaerosporus Pat., Tab. an. fasc., p. 101, No. 226. 1884.
Crepidotus variabilis var. sphaerosporus (Pat.) Quél., Ench. Fung., p. 108. 1886.
Claudopus sphaerosporus (Pat.) Sacc., Syll. Fung. 5: 734. 1887.
Dochmiopus sphaerosporus (Pat.) Pat., Hymen. Europe, p. 113. 1887.

Illustration: Fig. 168.

Pileus 8-20 mm broad, sessile, white, silky or villose, reniform or conchate, expanding to semiorbicular, margin at times lobed, pubescent, and somewhat incurved. Context thin and white; odor and taste mild.

Lamellae white then ocher-brownish with a flush of pinkish-brown, medium broad, subdistant, lamellulae variable in number.

Spores (6) 6.5-8 x 5.5-7.5 µ short- and broadly-ellipsoid to subglobose, more rarely globose, spinulose-punctate to echinulate. Basidia 25-32 x 6-8 µ, 4-spored. Pleurocystidia none; cheilocystidia 27-62 x 5-10 µ, cylindric, clavate, obclavate, ventricose, apices rounded, or often forked, branched or knobbed. Gill trama interwoven, hyphae 3-5 µ broad. Cuticle not sharply differentiated, the surface bearing a turf of colorless, narrow (2-4 µ), often crooked or coiled hyphae. Clamp connections present.

Habit, Habitat, and Distribution: On hardwood, Europe.

Material Studied: FRANCE: Josserand (MICH 66267).

Observations: This species name is often placed in synonymy with C. cesatii; but on the basis of material we have seen, C. sphaerosporus differs from C. cesatii, which has longer, ellipsoid spores and straight (not coiled) epicuticular hyphae. At this point we refer to the paper by Favre (1935) in which he reports the spores of C. sphaerosporus to be 6-10 x 4.5-8 µ. Further critical studies of authentic material should provide additional evidence of their differences, if any. For the present, we are recognizing both C. cesatii and C. sphaerosporus as distinct species. Thus far we have seen no North American material which we would refer to either C. cesatii or C. sphaerosporus, but we have included them for comparison, and on the possibility that one or both may still be found here.