Summary: Features include olive-brown or grayish brown, flat to funnel-shaped cap that often has a shallowly ribbed margin when mature, close whitish gills, brownish club-shaped stem, mild odor and taste, habitat on or near rotting logs, white spore deposit, and spindle-shaped spores.
Gills: "decurrent, close, narrow; whitish to cream", (Phillips), long-decurrent, when old with decurrent ridges running down stem, close or rarely subdistant, narrow to moderately broad, interveined at times, "frequently forked when young but rarely so when expanded"; whitish to cream-colored ("cartridge buff" or "pale pinkish buff"), (Bigelow)
Stem: 5-18cm x 1-3cm, enlarged toward the base, stuffed, sometimes curved; brownish; finely felty and furrowed, (Phillips), 5-13(18)cm x 0.9-1.7(3)cm at top, "equal or either end enlarged", stem stuffed, slightly curved at times; light olivaceous brown; fibrillose-striate, basal tomentum sparse, (Bigelow)
Odor: not distinctive (Phillips, Bigelow)
Taste: not distinctive (Phillips, Bigelow)
Microscopic spores: spores 8-11 x 4-5.5 microns, broadly spindle-shaped, smooth, inamyloid, (Phillips), spores (6)8-10(11) x 4-5.5 microns, broadly fusoid, inequilateral in side view, smooth, inamyloid; basidia mostly 4-spored, occasionally 1-, 2-, or 3-spored, 24-36(43) x 6-8.5 microns; [pleurocystidia and cheilocystidia presumably absent]; clamp connections present, (Bigelow)
Spore deposit: white (Phillips, Bigelow)
Notes: It has been found at least in WA, OR, ID, CA, and there is voucher from BC at the University of British Columbia.
EDIBILITY
no (Phillips)
Habitat and Range
SIMILAR SPECIES
Ampulloclitocybe clavipes is lighter in color, with different spores (Bigelow). A. clavipes has a gray-brown cap and an enlarged, spongy stem base, (Lincoff). Other differentiating features of A. clavipes are habitat on ground and smaller size range. The habitat is different but A. avellaneialba can grow on buried wood, and the clearest differentiating factor is the spores, (M. Beug, pers. comm.). Arora gives gills white then yellowish buff in age for A. clavipes and stem pallid with grayish or sordid olive-buff fibrils, whereas both stem and gills are white for A. avellaneialba, but these differences do not agree with other descriptions. A. clavipes is typically lighter in color but there is color overlap. Note that typical collections of A. clavipes in the Pacific Northwest are less clavate than in other parts of the continent. Gerronema atrialba grows on hardwood, has a scaly stem, and has amyloid spores of different shape.
Habitat
"in groups or clusters on or near rotting logs and debris of alder and conifers", (Phillips), gregarious on very decayed logs and other woody debris (often buried) under conifers, September into December, (Bigelow), fall, winter