The North American Species of Crepidotus

108. Crepidotus alnicola sp. nov.

Illustrations: Figs. 26, 182.

Pileus 1-2 cm latus, sessilis, ungulatus demum dimidiatus, albus, fibrillosus, margine incurvatus. Lamellae albae deinde "pinkish cinnamon" vel colore obscuriore, latae, confertae vel subdistantes. Sporae (6) 7-9 x (3.5) 4-5.5 µ, ellipsoideae, punctatae. Basidia 34-48 x (5) 6-7 µ, tetraspora. Pleurocystidia desunt; cheilocystidia 38-75 (200) x 3-9 µ, saepe gelatinosa et tramalia. Cuticula gelatinosa, hyphas erectas sine colore gerens. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum prope Burt Lake, Mich., July 24, 1963, A. H. Smith 66901.

 Pileus 1-2 cm broad, sessile, ungulate to dimidiate, snow white, appressed- to matted-fibrillose, margin incurved, slightly fimbriate. Context thick, rubbery-cartilaginous, white or watery-white; odor and taste none.

Lamellae pure white becoming pinkish cinnamon or darker, broad, close or subdistant, edges white fimbriate.

Spores (6) 7-9 x (3.5) 4-5.5 µ, ellipsoid, slightly inequilateral in profile, obscurely punctate, near "cinnamon" in deposit, ochraceous in 2% KOH. Basidia 34-48 x (5) 6-7 µ, 4-spored. Pleurocystidia none; cheilocystidia 38-75 (200) x 3-9 µ filamentous to cylindric, at times capitate, occasionally forked, the longer ones tramal and somewhat gelatinous. Subhymenium gelatinous. Gill trama subparallel, hyphae 5-9 µ broad. Pileus trama interwoven. Cuticle a gelatinous zone, 175-350 µ thick, bearing a turf of slender (3-7 µ), colorless, more or less flexuous, septate hyphae. Clamp connections present.

Habit, Habitat, and Distribution: On Alnus incana, Michigan, July.

Material Studied: MICHIGAN: Smith 66901 (type, from Burt Lake, July 24, 1963), 66979.

Observations: This species resembles C. betulae, but that has smooth spores. The punctate spores and gelatinous cuticle are distinctive features of C. alnicola.