The North American Species of Crepidotus

47. Crepidotus pallidobrunneus sp. nov.

Illustrations: Figs. 12, 104, 105.

Pileus (4) 8-30 mm latus, sessilis, conchatus, convexus demum spatulatus, pallidofuscus demum obscuro-cinnamomeus vel pallido-"Sayal brown," glabrosus vel pubescens, striatulatus. Lamellae confertae, latae, pallidae demum "Sayal brown" vel obscurocinnamomeae. Sporae 4.5-6 µ globosae vel subglobosae, minimum punctatae. Bisidia 20-28 x 5-7 µ, tetraspora. Pleurocystidia desunt; cheilocystidia 30-66 x 4-8 (13) µ. Cuticula ex hyphis repentibus composita, hyphas erectas et pileocystidia gerens. Fibulae adsunt. Specimen typicum in Herb. Univ. Mich.; lectum prope Emerson, Mich., Aug. 12, 1963, A. H. Smith 67120.

Pileus (4) 8-30 mm broad, sessile, conchate, convex to spathulate, pale tawny to dull cinnamon or pale "Sayal brown," glabrous to more or less downy-pubescent, striatulate when fresh. Context thin, fragile; odor and taste mild.

Lamellae close, broad, pallid at first, finally "Sayal brown" or dull cinnamom, edges fimbriate.

Spores in deposit dull cinnamon, 4.5-6 µ in diameter, globose or subglobose, minutely punctate. Basidia 20-28 x 5-7 µ, 4-spored. Pleurocystidia none; cheilocystidia 30-66 x 4-8 (13) µ, cylindric, ventricose, to obclavate. Gill trama subparallel, hyphae 4-9 µ broad. Pileus trama interwoven, at times loosely so. Cuticle of repent hyphae, bearing erect hyphae with terminal elements as pileocystidia at times with a brownish content. Clamp connections present.

Habit, Habitat, and Distribution: On hardwood sticks and logs, Michigan, July-August.

Material Studied: IDAHO: Smith 54330; MICHIGAN: Smith 63674, 67120 (type, on twigs, Emerson, Aug. 12, 1963), 67133, 67138, 67139.

Observations: This is near C. sublatifolius, from which it is distinguished chiefly by its lack of pleurocystidia.