The North American Species of Pholiota

132. Pholiota humii sp. nov.

Illustrations: Text figs. 281-284.

Pileus 1-3 cm latus convexus, viscidus, glaber, vinaceo-brunneus. Contextus pallidus, graveolens. Lamellae adnatae demum subdecurrentes, pallidae demum luteae, confertae, subangustae. Stipes 2.5-4 cm longus, (1.5) 2-5 mm crassus, aequalis deorsum vinaceo-brunneus, sursum pallidus demum luteus. Sporae 5.5-7 x 4-4.5 (5) µ. Pleurocystidia 45-75 x 9-17 µ, fusoide ventricosa, obtusa, crassotunicata. Specimen typicum in Herb. Univ. Mich. conservatum est; legit prope "Heaven's Gate, Seven Devils Mts.," Idaho, 5 Juli, 1958, Smith 58633.

Pileus 1-3 cm broad, convex, expanding, viscid, when young dark vinaceous brown ("natal-brown" to "Verona-brown"), later the disc "army-brown," finally reddish tawny, the margin paler brown, glabrous, even. Context pallid; odor fragrant (like green corn), taste slight; FeSO4—bright green.

Lamellae adnate to subdecurrent, at first whitish, then brown, close, medium narrow.

Stipe 2.5-4 cm long, (1.5) 2-5 mm thick, with scattered fibrils, pallid or pale tawny, base dull vinaceous brown ("army-brown"), equal. Veil arachnoid, yellowish.

Spores 5.5-7 x 4-4.5 (5) µ in face view ovate to elliptic, in profile somewhat bean-shaped to subelliptic, wall relatively thin (± 0.2 µ) and apical pore a very minute spot (under 1.4 NA ob.). In KOH dingy ochraceous tawny, in Melzer's reagent paler but more cinnamon.

Basidia 19-24 x 6-7.5 µ, 4-spored, yellow in KOH or in Melzer's reagent, narrowly clavate. Pleurocystidia 45-75 x 9-17 µ, abundant, fusoid-ventricose with obtuse apex, wall up to 3 µ thick in ventricose part, thin-walled at obtuse apex; content ochre-yellow when first revived in KOH, slowly fading, homogeneous; wall in neck somewhat flexuous; surface smooth. Cheilocystidia 30-45 x 9-14 µ, broadly subfusoid, subelliptic-pedicellate, or fusoid-ventricose with obtuse apices, both thin-walled and thick-walled cells intermingled. Caulocystidia abundant, broadly fusoid, 35-70 x 10-20 µ, thin-walled or wall thickened (0.4-1 µ), hyaline, content homogeneous.

Gill trama with short- to long-celled hyphae more or less in parallel arrangement, the cells becoming inflated in age, 6-12 (20) µ broad; walls thin, hyaline to yellowish in KOH, smooth; subhymenium of narrow (-3 µ) gelatinous interwoven smooth-walled hyphae, hyaline in KOH, near gill edge the zone at times so broad as to nearly obscure the floccose central strand. Pileus cutis a gelatinous layer of appressed-interwoven narrow (2-5 µ) yellowish hyphae, those near the hypodermium conspicuously incrusted (not so at upper edge of layer); hypodermium of floccose hyphae 5-12 µ diam. with coarse dark rusty brown pigment incrustations. Context hyphae yellowish to hyaline in KOH, cells inflated to 15 µ or more, thin-walled and smooth. All hyphae inamyloid. Clamp connections present.

Habit, Habitat, and Distribution: Gregarious to scattered on or around rotten conifer logs. July and August, Idaho, Smith 58633, type.

Observations: This species is characterized by the vinaceous brown pileus, truly thick-walled pleurocystidia, whitish gills at first (but they soon become yellow) and fragrant odor. P. vinaceobrunnea has much longer pleurocystidia, lacks a fragrant odor and has well-developed whitish veil. We found caulocystidia on the stipe of P. humii but not on P. vinaceobrunnea but the comparison was made from dried specimens and we have some reservations concerning it.

Material Examined: IDAHO Smith 38633, 73893, 59054, 60696.