The North American Species of Crepidotus
20. Crepidotus nyssicola (Murr.) Singer, Lilloa 13: 89. 1947.
Pleuropus nyssicola Murr., Lloydia 5: 145. 1942.
Illustrations: Figs. 62, 63.
Pileus 3-6 cm broad, deeply depressed with an arched margin, becoming piano-depressed or vase-shaped, finely hispid or subglabrous, white to cremeous or pale purplish with dark purple lines, margin faintly striatulate when moist. Context thin, pallid; odor mild or resembling that of Calvatia gigantea.
Lamellae decurrent, close, narrow, white becoming "clay color" to "sayal brown," edges flocculose.
Stipe 1-3 cm x 4-8 mm, central or eccentric, fleshy-tough, white or pallid, pubescent or sub-scaly. Veil none.
Spores 5-7 (7.8) x 5-6 µ, globose to subglobose, frequently ovoid, echinulate, wall medium thick. Basidia 21-32 x 6-7 (8) µ, 4-spored. Pleurocystidia none; cheilocystidia 24-61 x 6-10 µ, cylindric-capitate, clavate, at times more or less constricted. Gill trama subparallel, hyphae 5-10 µ broad. Pileus trama: (a) in tangential sections more or less pseudoparenchymatous; (b) in radial sections, the hyphae radial and more or less subparallel or slightly interwoven. Cuticle of repent hyphae, with occasional uplifted ends. Clamp connections present on the cuticular hyphae.
Habit, Habitat, and Distribution: On hardwood and conifer logs, Florida and Michigan, April, August, and October.
Material Studied: FLORIDA: Murrill F 19730, type, on Nyssa biflora, Gainesville, April 20, 1939; MICHIGAN: Smith 33169, 61289.
Observations: The description of microscopic characters above is based on a study of the type. Smith's Michigan collections are in essential agreement with the type, with some variation in the size of the cheilocystidia, and the extent of pileocystidia .