Summary:
Fieldmarks include 1) a non-viscid cap that is orange-yellow to orange brown on the disc, and yellowish to greenish yellow toward the margin, 2) a cap margin often hung with veil remnants, 3) yellow to greenish-yellow gills, 4) a long yellowish to brownish dry stem that often develops rusty or brown stains from the base up, 5) a bitter taste, 6) clustered fruiting on wood, and 7) dark spores. It is common in the Pacific Northwest.

Cap:
(1)2-5(9)cm across, at first broadly conic or bell-shaped, soon becoming convex, then broadly umbonate to flat; "bright sulfur-yellow to greenish-yellow, or at times yellow-orange (especially when young), the center sometimes darker (orange-tan to orange-brown)"; smooth, not viscid, "margin often hung with small veil remnants", (Arora), 2-6cm across, convex becoming flat, often with a small umbo, margin incurved for a long time, acute; orange-yellow to orange-brown on disc, increasingly sulphur-yellow to greenish toward margin; smooth, dull, margin with yellowish veil remnants when very young, (Breitenbach)

Flesh:
thin; yellow, (Arora), thin; light yellow, (Breitenbach)

Gills:
typically adnate but sometimes seceding, close; "at first sulfur-yellow, becoming greenish-yellow or olive, then finally dusted purple-brown to nearly black with spores", (Arora), notched, 50-55 reaching stem, 5-7 subgills between each pair of gills, broad; sulphur-yellow when young, then greenish to dingy gray-green; edges smooth, (Breitenbach)

Stem:
5-12cm x 0.3-1(1.5)cm, equal or narrowing downward, firm, often curved or sinuous; "yellow to tawny, but often developing rusty or brownish stains from base upward"; dry, (Arora), 4.0-9.0 x 0.3-0.7cm, cylindric, often bent, joined with others at base, solid becoming hollow; sulphur-yellow, when old reddish-brown toward the base, with a light yellow ring zone on upper third when very young; smooth, finely longitudinally fibrillose, (Breitenbach)

Veil:
thin, pale yellow, evanescent [fleeting], or leaving slight remnants on cap margin or an obscure fibrillose zone on stem which is subsequently blackened by spores, (Arora)

Odor:
pleasant (Phillips), polyporoid (Breitenbach), none (Miller)

Taste:
very bitter (rarely mild), (Arora), "bitter and astringent after being chewed for a time" (Breitenbach)

Microscopic spores:
spores 6-8 x 3.5-5 microns, elliptic, smooth, with germ pore; chrysocystidia present on gill faces, (Arora); spores 6.5-8 x 3.5-4 microns, elliptic to slightly oval, smooth, with apical germ pore; basidia 4-spored, 17-21 x 5-6 microns, colorless to yellowish in KOH; pleurocystidia very abundant, 26-42 x 6-11 microns, "ventricose with an abruptly narrowed and prolonged apex, or mucronate, some buried in the hymenium, some projecting somewhat, some arising from the gill trama, yellowish as well as highly refractive in KOH, some merely with a highly refractive central body", cheilocystidia 18-32 x 6-10 microns, obtusely fusoid-ventricose; "gill trama more or less regular, yellowish in KOH"; cap trama with the cuticle scarcely differentiated, "beneath it a somewhat differentiated hypoderm, the remainder interwoven and floccose, when revived in KOH often with an orange-brown zone beneath the hypoderm and yellow toward the subhymenium"; clamp connections present, (Smith(25)), spores 5.8-7.3 x 3.5-4.3 microns, elliptic, smooth, thick-walled, with germ pore, gray-yellow; basidia 4-spored, 20-23 x 5-6 microns, +/- cylindric, with basal clamp connection; pleurocystidia modified as chrysocystidia, 28-45 x 7-11 microns, "lageniform, with an apical protrusion", cheilocystidia 20-38 x 6-9 microns, "obtusely lageniform, ventricose"; cap cuticle of periclinal hyphae 2.5-9 micron wide, "some encrusted and with intracellular pigmentation", some septa with clamp connections, with cellular, nearly spherical to oblong elements below them, with intracellular pigmentation, 10-30 microns across, sometimes with interspersed lactifer-like hyphae 3-6 microns wide, (Breitenbach)

Spore deposit:
"purple-brown to deep purple-gray" (Arora), wine-brown (Breitenbach)

Notes:
Smith(25) examined collections from BC, WA, OR, ID, AL, CA, MT, NC, and TN. Breitenbach(4) give the distribution as North America, Europe, Asia, and North Africa.

EDIBILITY

poisonous, gastrointestinal upset in North America, several deaths in Europe and Asia, (Arora)

Synonyms and Alternate Names:
Naematoloma fasciculare (Huds.: Fr.) P. Karst.