The North American Species of Crepidotus
6. Crepidotus putrigenus (Berk. & Curt.) Sacc., Syll. Fung. 5: 883. 1887.
Agaricus putrigenus B. & C., Ann. Mag. Nat. Hist. III: 4: 292. 1859.
Crepidotus malachius var. plicatilis Pk., New York State Mus. Nat. Hist. Rept. 39: 71. 1886.
Illustration: Fig. 39.
Pileus 1-5 cm broad, sessile, subreniform, densely imbricate, dingy-white, tomentose or finally more or less glabrescent, moist, margin slightly striate.
Lamellae nearly close to crowded, broad, dingy-white then rusty brown to dull cinnamon.
Spores (4) 4.5-7 µ in diameter, globose or subglobose, many more or less ovoid, punctate, brownish, wall medium thick. Pleurocystidia none; cheilocystidia 25-46(71) x 6-10(15) u, clavate, cylindrical, at times ventricose or constricted, apices obtuse, at times capitate, often repent on the gill edges (in dried material). Gill trama subparallel, hyphae 3-6 µ or more broad. Pileus trama interwoven. Cuticle repent, with scattered, more or less erect hyphae, at times with pileocystidia resembling the cheilocystidia. Lactifers present in the pileus trama. Clamp connections none.
Habit, Habitat, and Distribution: On decaying hardwood, New York, Michigan, South Carolina, summer.
Material Studied: MICHIGAN: Smith 25512, 37186, 63439, 63521, 63529, 63530, 63602; NEW YORK: Peck, type (NYS) of C. malachius var. plicatilis; SOUTH CAROLINA: Curtis No. 2566, (K) type, collected by Ravenel and sent to Berkeley.
Observations: The type at Kew was not found in satisfactory condition for critical observations; cheilocystidia were difficult to find, but clearly there is a lack of clamp connections. The species shows some variation in the ornamentation of the pileus (it may be fibrillose or more or less glabrous), and the gills vary somewhat in width and spacing. It differs from malachius and nephrodes, with which it has been confused, in its lack of clamp connections. We believe that Peck's C. malachius var. plicatilis is C. putrigenus.