Summary:
Features include a dark brown to red brown, umbonate cap, pallid young gills, a whitish stem that darkens from the base upward, a membranous veil that is striate on the upper surface, mild odor and taste, woodland habitat, dull brown to dark brown spore deposit, large spores, and 2-spored basidia. Breitenbach(4) give Agrocybe brunneola (Fr.) Watling as a synonym of Agrocybe erebia (Fr.) Kuehner (itself a synonym of Cyclocybe erebia), but Watling describes them separately.

Gills:
"uncinate to adnate often with distinct tooth, rather distant, broad"; "pale clay buff or milky coffee at first then almost date brown", margin white; margin flocculose, (Watling), "adnate to often decurrent; pallid then deep umber brown", (Phillips) adnate to +/- decurrent, subdistant, broad, interveined; pale brown then rust brown, (Hermanson), attached to slightly decurrent, close to subdistant, often interveined, pale brown becoming dull brown at maturity, (Bessette)

Stem:
2-6cm x 0.35-0.8cm, equal or slightly swollen; "whitish throughout at first, darkening to cigar brown from base upwards with age"; striate in upper part (striations often joining up with gills), silky fibrillose in lower part, (Watling), 6-8cm x 0.6-1.2cm, equal; whitish, then darkening brown from base upward, (Phillips), 3-7cm x 0.3-1cm, equal; pallid near top, dull brown lower down; fibrillose in lower part and pruinose near top, (Hermanson)

Veil:
"ring membranous, narrow, white, striate above, soon collapsing", (Watling), ring prominent when young but soon torn and easily lost, whitish with striations superiorly, (Phillips), membranous, pallid, thin, tends to collapse, ring sometimes disappears, (Hermanson)

Odor:
not distinctive (Watling, Phillips)

Taste:
pleasant (Watling), not distinctive (Phillips)

Microscopic spores:
spores 9-13(15) x (5)6-7 microns, elongate elliptic in face view, slightly boletoid in side view, ochraceous in water and alkali, germ pore absent; basidia 2-spored, cylindric-clavate, colorless; pleurocystidia few to numerous, lageniform, 50-80 x 12-16 microns, head obtuse ((4)6-9 microns broad), colorless, granular-punctate at apices, cheilocystidia variable, vesiculose to ventricose or even clavate, 30-60 x 8-25 microns, colorless; cap cuticle "a hymeniform layer of balloon-shaped to pyriform cells" 9-15 microns broad; stem cuticle of filamentous hyphae supporting at stem-apex sterile cells similar to cheilocystidia; clamp connections not seen, (Watling), spores 11-15.5 x 5-6.5 microns, elliptic, (Phillips), spores 11-15.5 x 5-6.5 microns, germ pore absent, apex snout-like; basidia 2-spored; pleurocystidia 50-75 x 9-15 microns, narrowly fusoid-ventricose [spindle-shaped - wider in middle], apex obtuse, cheilocystidia 26-35 x 10-16 microns, ventricose and apex broadly rounded, or similar to pleurocystidia, (Hermanson)

Spore deposit:
dull brown (Phillips, Bessette), very dark brown (Hermanson), snuff brown (Watling)

Notes:
There are collections from BC deposited at the University of British Columbia. There are collections from WA, OR, ID, ON, and NY at the University of Washington.

EDIBILITY

no (Phillips), unknown and too easy to confuse with poisonous species (Hermanson)

Synonyms and Alternate Names:
Agrocybe erebia "(Fr.) Kuehner ex Singer, Schweiz. Z. Pilzk."