Summary: Features include a slimy, dark olive-gray-brown cap, white gills, a long slender slimy white stem, and large spores. The description is derived from Hesler(1) except where noted.
Cap: 2-5cm across, at first broadly bell-shaped with mammillate umbo and incurved margin, becoming flat; 'surface beneath "buffy olive" with the umbo "clove brown," margin slightly paler'; glutinous from colorless veil, bald, "the surface often uneven from the drying gluten", margin membranous, (Hesler), dark olive-gray-brown, becoming paler at the margin, (Stuntz)
Flesh: thin; white, unchanging; in stem white
Gills: adnate with a tooth becoming subdecurrent, close to subdistant, 0.3-0.4cm broad, thickish, waxy, a few forked; pure white
Stem: (4)5-10cm x 0.3-0.6(0.8)cm, equal or slight ventricose [wider in middle] and narrowed at base; whitish, when old tinted like cap from the drying veil; covered at first with the colorless glutinous sheath, (Hesler), lacking a sheath of fibrils beneath the slime sheath (Stuntz)
Veil: colorless glutinous veil on cap and lower stem
Microscopic spores: spores (10)12-18(20) x 7-9 microns, elliptic, smooth, inamyloid; basidia 4-spored, 55-71 x 7-12 microns; pleurocystidia and cheilocystidia absent; gill tissue divergent; clamp connections present on cuticular hyphae
Spore deposit: [presumably white]
Notes: Hesler(1) examined collections from WA, OR, and CA. There is a collection from BC at the University of British Columbia.
EDIBILITY
Habitat and Range
SIMILAR SPECIES
Hygrophorus ''olivaceoalbus'' var. gracilis is similar but H. megasporus lacks dark fibrils beneath stem slime, has a bald cap, and has much larger spores, (Hesler).
Habitat
scattered to single or rarely subcespitose [nearly tufted] on humus or mossy areas, in dense coniferous forests