Summary:
Gymnopilus picreus is distinguished (Hesler) by color, a finely scaly cap [although Moser says bald, and Bessette smooth then scurfy], narrow rusty-staining gills, an umber to fulvous stem with a white powdery appearance, absence of a veil, caulocystidia in tufts or palisades, and pileocystidia of two general types (as scattered terminal elements and as mounds). Other features include a cinnamon brown to dark red-brown, moist cap, thin cap-colored flesh, adnate to decurrent, close to crowded gills that are yellow when young, a mild to bitter taste, and growth on wood.

Cap:
1-2(5)cm across, convex to bell-shaped - convex, then expanded; hygrophanous, rufous to baybrown-cinnamon [sic]; moist, non-viscid, scurfy, disc subsquamulose [somewhat fine-scaly], rarely rimulose-papillate, (Hesler), 2-4(6)cm across, convex; cinnamon-brown to dark red-brown, margin sometimes lighter, dries yellow-brown to yellow; bald, (Moser)

Flesh:
thin, colored as cap, (Hesler)

Gills:
"adnate to decurrent, sometimes seceding", close, narrow; "yellow to dull ochraceous, then ferruginous, sometimes staining rusty", (Hesler), crowded, gold-yellow, yellow, (Moser), "bright yellow when young, becoming ochraceous and sometimes staining rusty", (Bessette)

Stem:
5-8cm x 0.2-0.5cm, widening slightly downward, hollow, straight; "umber to fulvous, darkening from the base up"; white-pulverulent [white-powdery] when young, glabrescent [becoming bald], (Hesler), 1.2-5.5cm x 0.2-0.6cm, yellow-brown to red-brown, sometimes fairly dark; "young white-frosted, lower bald", (Moser)

Veil:
none (Hesler)

Odor:
not distinctive (Bessette)

Taste:
mild or bitterish, (Hesler), not distinctive or slightly bitter (Bessette)

Microscopic spores:
spores 7-9(9.5) x 4.5-5.5(6) microns, elliptic to nearly oval in face view, slightly inequilateral in side view, verruculose [finely warty], ferruginous in KOH, dextrinoid, no germ pore; basidia 2-4-spored, 23-28 x 5-6 microns; pleurocystidia 27-35 x 6-8 microns, ventricose, cheilocystidia 23-33 x 4-7 microns, "ventricose, capitate or non-capitate, at times with a brown pigment"; gill trama subparallel, hyphae 3-5 microns wide, subhymenium not distinctive; cap trama radial, cap cuticle "of radially disposed, repent, brown, incrusted hyphae, at times more or less erect, the terminal elements as pileocystidia" measuring 25-45(76) x 6-20 microns, clavate, "and at intervals the surface with mounds of brown, clavate pileocystidia" measuring 24-32 x 5-9 microns; caulocystidia 30-62 x 5-17 microns, "flask-shaped, capitate, scattered, or in tufts, or forming a turf"; cap and gill trama dark brown in KOH, reddish brown in Melzer''s reagent; yellow pigment, soluble in KOH, present in gill trama; clamp connections present, (Hesler), spores 8-10 x 5-6 microns, (Moser)

Spore deposit:
ochraceous orange (Bessette)

Notes:
Hesler examined material from WA, OR, ID, ON, QC, CA, ME, MI, NY, TN, VT, and Sweden. There is a collection from BC by P. Kroeger at Pacific Forestry Centre and several from BC by O. Ceska at the University of British Columbia. A collection from Finland was used by Guzman-Davalos(2).

EDIBILITY

unknown (Bessette)

Synonyms and Alternate Names:
Fulvidula picrea (Pers. ex Fr.) Singer
Naucoria belluloides Kauffman