Summary:
Also listed in Truffles etc. category. Subgenus Myxacium. Section Myxacium. Features include 1) a viscid to greasy smooth cap that is buff to olive-yellow to dingy yellow-brown or dark brown, 2) a spore mass of contorted plates and chambers that is yellowish becoming dull brown to pale or dark cinnamon-brown, 3) a stem-columella with a with similar range of color to the cap but often purple or lilac where exposed to light, 4) a yeasty odor and unpleasant taste, 5) growth above the ground or underground under conifers especially in the mountains, 6) brownish spores that are warty and sometimes wrinkled, and 7) basidia 4-spored, a few 2-spored. Several other Thaxterogaster species occur in the United States, some undescribed (Arora). Cortinarius pinguis is an abundant sequestrate species in the Pacific Northwest (Trappe(13)).

Cap:
1-5cm across, "rounded or obtuse to convex or lobed", the top often flattened somewhat when old; "buff to olive-yellow to dingy yellow-brown or dark brown"; "slightly viscid to slimy when moist, smooth"^, (Arora), 1-5cm across, usually not as high as broad, depressed-spherical, flattened or convex, in many collections rather misshapen, the spore mass completed enclosed or lower part of spore mass exposed; olive-yellow ("honey yellow" to "Isabella color"), darkening when old to deep dingy yellow-brown ("bister"), at least on the disc; glutinous or strongly viscid when wet, bald, smooth, rarely splitting vertically, (Singer), ocher to olive yellowish; greasy, (Phillips)

Flesh:
firm; "white or tinged cap color"^, (Arora), fleshy; pale dull honey-color fading to pallid, (Singer)

Gills:
spore mass composed of crowded, contorted plates and/or small chambers; "yellowish becoming dull brown" to pale or dark cinnamon brown, (Arora), 0.6-1cm deep, "cinnamon buff" becoming "cinnamon"; loculate [chambered] with irregular chambers up to 0.1-0.15cm in diameter, chambers usually not extended in gill-like fashion but if so with anastomosing veins to produce a reticulate appearance, the gill-like development almost always most significant near lower part of spore mass where the spore mass has come free from the columella (generally when cap horizontally expanded), the spore mass separating in some the full length of the columella and in others not at all, (Singer)

Stem:
0.5-4.5cm x 0.8-2.5cm, "very short or rudimentary in some forms", well developed in others, equal or swollen at base, percurrent [going through spore mass]; "dull yellowish to buff or colored like the cap, often purple or lilac where exposed to light"; "smooth, often viscid near base when moist", (Arora), 1.0-4.5 x 0.8-2.5cm, always well developed, but short, more or less equal or widening downward, stuffed; purple, possibly from gluten as not purple when dried or preserved; glutinous, smooth, bald; columella continuous with stem and sometimes completely exposed by separation of the spore mass but not glutinous or purple but rather dry and yellowish, almost equal or only slightly narrowing upward, (Singer)

Veil:
"fibrillose or cobwebby, persisting or disappearing", (Arora), glutinous, sometimes forming a ring when mature but this ring often not persistent, the veil colored as the surface of the stem but soon fading, (Singer)

Odor:
yeasty (Phillips), not distinctive (Singer)

Taste:
unpleasant (Phillips), not distinctive (Singer)

Microscopic spores:
spores (12)14-16.5 x 8-9.5 microns, elliptic to somewhat oblong, warty and/or wrinkled, (Arora), spores (12)14-16.5(20) x (6.5)8-9.5(10.8) microns, elliptic to elliptic-oblong or oval-oblong, verrucose from a bright and deep rusty ornamentation that is coarser in many spores on or near the apex, (the ornamentation exosporial with a distinct episporium and endosporium underneath and at times a demonstrable thin perisporium over the exosporium), hilar appendage obliquely inserted, rarely basal, spores remaining attached to sterigmata even at maturity; basidia 4-spored, a few 2-spored, 28-35.5 x 9-11.5 microns, colorless, a few fulvous in dried material, clavate, sterigmata acute and often half-sickle-shaped, basidioles spherical; few pseudoparaphysoid bodies present; cystidia none; trama of tramal plates regular, some aggregations of hyphae fulvous in dried material but most single hyphae colorless, with thin-walled clamped hyphae; peridial hyphae "similar and the peridium showing an enormously extended gelatinous pellicle-like outer layer" which is at least 100 microns thick (as revived in KOH), the pellicle consisting of narrow, loosely arranged, colorless, thin-walled, smooth hyphae embedded in a gelatinous mass; all hyphae with clamp connections, (Singer), spores brownish in 3% KOH (Phillips)

Spore deposit:
not obtainable

Notes:
Collections of Cortinarius pinguis were examined from WA, OR, ID, CA, and WY, and the distribution includes CO, (Singer). It has also been found in western AB (Kernaghan) and BC (collection by Oluna Ceska at University of British Columbia; Paul Kroeger, pers. comm.).

EDIBILITY

unknown (Arora), not edible, it is thought, (Phillips)

Synonyms and Alternate Names:
Hapalopilus salmonicolor (Berk. & M.A. Curtis) Pouzar Ceska
Polyporus salmonicolor Berk. & M.A. Curtis
Thaxterogaster pinguis (Zeller) Singer & A.H. Sm.