The North American Species of Pholiota

48. Pholiota nigripes sp. nov.

Illustrations: Text figs. 146-148.

Pileus 0.8-3.5 cm latus, late convexus, glabrosus, lubricus, obscure "buckthorn brown" recens, deinde opacus demum cinnamomo-brunneus deinde "ochraceous tawny" vel "pinkish buff," margine leviter striatus. Caro tenuis, aquosa, concolor; odore et gustu mitis. Lamellae depressoadnatae, secedens, furvo-coriaceae recentes, confertae, latae. Stipes 3-6 cm longus, 1.5-2.5 mm crassus, infra brunneus vel niger, sursum pallide "buckthorn brown," glaber. Velum deest. Sporae 7-9.5 x 3.8-4.5 (5.3) µ, ellipsoideae demum oblongae, leves, truncatae. Pleurocystidia desunt; cheilocystidia 27-50 x 4-10 µ, fusoidea demum ventricosa, cervix longa, gracilis, sursum decrescens, apicibus acuta. Cuticula repens. Caulocystidia 27-54 x 4-10 µ, cheilocystidiorum similia. Specimen typicum in Herb. Univ. Mich.; lectum in Idaho County, Idaho, 27 June, 1962. Smith 65040.

Pileus 0.8-3.5 cm broad, margin incurved at first, pileus becoming broadly convex or remaining obtusely umbonate, surface glabrous, lubricous when fresh and moist, hygrophanous, pale "Buckthorn brown" (dark clay color) to cinnamon brown and fading to ochraceous tawny or finally pinkish buff, margin faintly striate before fading. Context thin, watery, concolorous with surface; odor and taste mild; no reaction with FeSO4.

Lamellae depressed-adnate and seceding, dingy butterscotch-color young, dull rusty brown in age, close, broad, edges minutely eroded.

Stipe 3-6 cm long, 1.5-2.5 mm at apex, equal or nearly so, dark rusty brown to blackish below, pale watery buckthorn-brown at apex, glabrous and naked or apex faintly pruinose, with a few faint fibrillose streaks below. Veil absent on all specimens observed.

Spores 7-9.5 x 4-5 (5.3) µ, ovate to elliptic or some nearly oblong in face view, in profile view ovate to obscurely inequilateral; smooth, relatively thick-walled (up to 0.5 µ); apical pore distinct but apex mostly slightly truncate; pale dull cinnamon to tawny in KOH, not changing color appreciably in Melzer's reagent.

Basidia 18-22 x 7.5-9 µ, 4-spored, clavate, hyaline in KOH, yellowish in Melzer's reagent. Pleurocystidia none. Cheilocystidia abundant, 27-50 x 4-10 µ, narrowly fusoid to fusoid-ventricose, tapered from a basal inflated area 5-10 p diam. to a neck 4-6 µ diam. midway to apex and apex acute to subacute, thin-walled, smooth, hyaline in KOH. Caulocystidia thin-walled, scattered or in groups, 36-50 x 9-15 µ and clavate or ventricose (6-12 µ) at base and tapered to an acute to subacute apex, neck often flexuous, portion below ventricose part often with ochraceous walls in KOH, otherwise walls hyaline.

Gill trama parallel to subparallel, the hyphal cells short and 5-10 µ wide, walls thin to slightly thickened but middle lamella not clearly evident, not gelatinous; subhymenium indistinct, not gelatinous; walls of hyphae nearly hyaline to dingy ochraceous in KOH and slightly more ochraceous brown in Melzer's reagent. Pileus cutis a thin layer of tubular hyaline subgelatinous hyphae 2.5-4 µ diam., walls smooth; hypodermial region of non-gelatinous thin-walled hyphae with pale dingy ochraceous walls in KOH, the cells inflated to 22 µ more or less, toward the gill trama the hyphae with slightly thicker walls but middle lamella not showing distinctly; all hyphae inamyloid (ochraceous orange to paler in Melzer's reagent). Clamp connections present.

Habit, Habitat, and Distribution: Caespitose on conifer logs, Idaho, June and July; Trueblood 18 (MICH); Smith 65040 type, 65059, 65225, 65323.

Observations: The absence of a veil is a distinctive feature, but buttons should be checked. The thin gelatinous pellicle may become obliterated in age and this may cause some trouble in placing some collections. The spores are distinctly larger than in P. atripes, the latter has a distinct veil, and its pilei are paler and yellower as dried.