The North American Species of Pholiota
141. Pholiota rufodisca sp. nov.
Illustrations: Text figs. 299-301.
Pileus (1) 3-6 cm latus, convexus vel obtuse-umbonatus, fulvo-aurantiacus, rufo brunneus vel ad marginem luteo-avellaneus, glaber, viscidus. Contextus luteus, tenuis. Lamellae adnatae vel subdecurrentes, angustae denum latae, confertae, pallide luteae demum luteo-brunneae. Stipes 3-6 (8) cm longus, (2) 3-6 (8) mm crassus, deorsum subfulvus, sursum luteus, velum fibrillosum, luteum. Sporae 5-7 x 3.5-4.5 µ. Pleurocystidia 50-73 x 11-17 µ fusoide ventricosa, crassotunicata. Specimen typicum in Herb. Univ. Mich. conservatum est. legit prope Payette Lakes, Idaho. 31 Aug. 1954. Smith 47146.
Pileus (1) 3-6 cm broad, convex, expanding, at times more or less umbonate, disc rusty orange to dark reddish brown, blackish when dried at times, marginal portion buff to yellowish gray, glabrous, viscid, margin incurved, even. Context thin, yellow.
Lamellae adnate or subdecurrent, yellowish when young, "buckthorn brown" at maturity, narrow to medium broad to broad, close.
Stipe 3-6 (8) cm long, (2) 3-6 (8) mm thick, yellowish and pruinose above, dingy downward, basal portion rusty brownish, equal, slightly fibrillose, glabrescent, stuffed then hollow. Veil yellowish, arachnoid.
Spores 5-7 x 3.5-4 µ, smooth, apical pore distinct and apex obscurely truncate in some, in shape elliptic to ovate, in profile obscurely inequilateral, dull tawny in KOH, paler in Melzer's reagent, wall thin (-0.25 µ).
Basidia 4-spored, 20-27 x 5-6 µ clavate, yellowish to hyaline in KOH, yellowish in Melzer's reagent. Pleurocystidia 50-73 x 11-17 µ fusoid-ventricose, apex obtuse; wall smooth and 1.5-2.5 µ thick, hyaline-refractive in KOH, content hyaline to yellow and homogeneous. Cheilocystidia 30-56 x 6-14 µ similar to pleurocystidia. Caulocystidia versiform, 40-80 x 12-25 µ, clavate, fusoid-ventricose, or fusoid, thin-walled, smooth, content "empty."
Gill trama a central area of floccose hyphae 4-12 µ broad; walls thin, yellowish to hyaline in KOH, smooth; subhymenium a gelatinous layer of narrow hyaline hyphae. Pileus cutis a thick gelatinous pellicle of narrow (2-3 µ) hyaline to yellowish hyphae, those near hypodermium incrusted; hypodermium a layer of floccose hyphae 4-8 (12) µ with heavy incrustations, fulvous in KOH. Context hyphae yellowish hyaline in KOH, cells inflated, walls thin, smooth. Clamp connections present. All hyphae inamyloid.
Habit, Habitat, and Distribution: On conifer wood and debris, Idaho, Oregon and Washington, August-October.
Observations: P. rufodisca is close to P. brunneodisca which Peck (1913) stated was slightly viscid. In our study of the type, however, we found no gelatinous pellicle. P. ferruginea lacks caulocystidia as far as our observations indicate. There is a difference in the degree to which the veil is developed also.
Material Examined: IDAHO: Smith 47146 (type), 47033, 70858, 71113. NEW MEXICO: Barrows 925, 141. OREGON: Smith 24733. WASHINGTON: Smith 47594, 47650, 48240.