Summary:
Tricholomopsis flavissima is distinguished by 1) slender stature, 2) a bright yellow color over all, 3) gills with brighter yellow edges than faces and appearing gelatinous under a hand lens, 4) a slightly peppery taste, 5) growth on conifer wood, 6) a white spore deposit, and 7) microscopic characters. It is uncommon.

Cap:
3-5cm across, "broadly convex becoming flatter and centrally depressed; even chrome yellow all over or darker on the center disc; dry and finely hairy, sometimes becoming more scaly on the disc and sometimes margin fringed with clusters of tiny hairs", (Phillips), 3-5cm across, convex becoming broadly convex; evenly yellow overall ("mustard yellow") or the disc darker and near "antimony-yellow"; "dry and innately fibrillose, or moist beneath the fibrils, either remaining fibrillose or becoming somewhat scaly around the disc, the fibrils near the margin sometimes arranged into fascicles" and the margin usually fimbriate [fringed] when young, (Smith(42))

Flesh:
dull yellow (Phillips), thin but nearly equal, 0.15-0.2cm thick, pliant; dull yellow, (Smith(42))

Gills:
adnate or notched, subdistant; strong yellow with brighter edges appearing gelatinous under lens, (Phillips), bluntly adnate but becoming +/- decurrent, close to subdistant, 24-30 reaching stem, moderately broad, about 0.5cm broad, subgills in 2 tiers; brightly yellow ("primuline yellow"), becoming "light orange yellow", edges a brighter yellow than faces; edges appearing gelatinous under a hand lens, (Smith(42))

Stem:
2-5cm x 0.3-0.6cm, "hollow, slightly curved; pale when young from thin, yellowish partial veil, the same color as cap; appressed, minute hairs", (Phillips), 2-5cm x 0.3-0.6cm, equal, hollow, fleshy; colored as cap when old, pallid when young from the thin, pale yellowish partial veil; appressed-fibrillose to the top when old, (Smith(42))

Veil:
stem pallid when young from the thin, pale yellowish partial veil, (Smith(42))

Odor:
faintly fragrant (Phillips, Smith(42))

Taste:
slightly peppery (Phillips, Smith(42))

Microscopic spores:
spores (6)7-9 microns in diameter, round or nearly round, smooth, inamyloid, pleurocystidia absent, cheilocystidia very abundant, 40-200 x 3-5 microns, "septate, filamentous, subgelatinous", yellowish to colorless when fresh, the pigment intracellular; cap epicutis consisting of greatly elongated hyphal cells (not inflated), the yellow walls thin or thickened, the apex of the end-cells merely rounded, smooth-walled; clamp connections present, (Smith(42)), spores 7-9 x 6-8 microns, round or nearly round, smooth, inamyloid, (Smith(15))

Spore deposit:
white (Phillips)

Notes:
It has been found at least in WA, OR, and ID, (Smith(42)). There are collections from BC at the University of British Columbia.

EDIBILITY

unknown (Phillips)