The North American Species of Pholiota

152. Pholiota molesta sp. nov.

Illustrations: Pls. 7a, 70b.

Pileus 2-4 cm latus, late convexus, pallide luteolus ("pale pinkish-buff"), viscidus. Lamellae pallidae angustae, confertae. Stipes 3-7 cm longus, 5-10 mm crassus, subalbidus, fibrillosus. Sporae 5.5-6.5 (7.5) x 3.5-4 µ. Pleurocystidia 45-66 (70) x 8-12 (16) µ in ligno semiusto. Specimen typicum in Herb. Univ. Mich. conservatum est; legit prope McCall, Idaho. 23 Juni 1962, Smith 65008.

Pileus 2-4 cm broad, broadly convex with an incurved margin which for a time is fringed with a thin layer of veil remnants, "pale pinkish-buff" overall (young), developing a reddish or brownish flush in age, thinly glutinous, glabrous except for minute veil particles or fibrils near margin, somewhat virgate. Context white; odor mild, taste fungoid. KOH slowly orange-yellowish, FeSO4—no reaction.

Lamellae adnate, pallid like pileus, becoming cinnamon-buff to wood-brown, crowded, narrow, edges even and concolorous.

Stipe 3-7 cm long, 5-10 mm thick, surface at first whitish-fibrillose overall and whitish beneath the fibrils, equal or narrowed downward, solid, watery pallid within, cortex whitish, not discoloring below, the fibrillose (veil) layer separating into zones or patches and becoming a dingy brownish orange, terminating as a faint annular zone, white and silky above the zone.

Spores 5.5-6.5 (7.5) x 3.5-4 µ, smooth, no apical pore present, in face view elliptic to ovate, in profile somewhat inequilateral, ventral line nearly straight as seen in optical section, dorsal line humped toward apiculate end or merely convex, wall about 0.3 µ thick, color in KOH dull cinnamon to dull tawny, in Melzer's reagent pale tawny.

Basidia 4-spored, 24-30 x 4.5-6 µ, hyaline in KOH, pale yellowish in Melzer's reagent. Pleurocystidia abundant, 45-66 (70) x 8-12 (16) µ, fusoid-ventricose with subacute to obtuse apex, wall thin smooth and hyaline, content homogeneous and hyaline, rarely with yellow to brown content. Cheilocystidia 28-45 x 8-15 µ, clavate to subfusoid or fusoid-ventricose, walls thin smooth and hyaline, content homogeneous and hyaline. Caulocystidia none found.

Gill trama of a central area of more or less parallel floccose hyphae hyaline or nearly so in KOH; hyphae 4-6 µ broad before cells inflate, walls thin to slightly thickened ("double"); subhymenium a distinctly differentiated layer of gelatinous hyphae. Pileus cuticle a thick gelatinous pellicle of hyphae 2-5 µ diam. walls smooth to roughened, hyaline to yellowish in KOH; hypodermium a layer of floccose hyphae with bright orange-rusty walls in KOH, walls mostly smooth. Context hyphae with thin to slightly thickened "double" walls, smooth, cells inflated. Clamp connections present. All hyphae inamyloid.

Habit, Habitat, and Distribution: On burned area, Idaho, June. Smith 65008, type.

Observations: The distinctive characters of this species include the pale pinkish-buff young pileus which develops a reddish or brownish flush, the short thick stipe the white veil which becomes dingy orange, and the separation of the veil into zones or patches on the stipe. These features distinguish it from other carbon-inhabiting species. The pale pileus of immature basidiocarps is the best feature for distinguishing the species from P. highlandensis in the field, and the lack of caulocystidia will distinguish it in the herbarium. Since in most Pholiota species the stipe darkens at the base we believe more observations on this non-darkening species are desirable.