Summary:
Features include 1) a convex, dry cap (with a small umbo) that is brown to orange brown, ribbed, and fibrillose-scaly, 2) white flesh, 3) sinuate, bone-colored gills serrated as in Lentinus, 4) a fibrillose, dry stem that is whitish near the top and pinkish tan lower down, 5) growth on wood, and 6) elongated spores. Heliocybe sulcata is widely distributed, especially on avalanche debris of aspen in the Rocky Mountains.

Cap:
up to 4cm across, ribbed over the gills like a small umbrella, "brown ribs over the gills, lighter in between, brown scales in cap centre, small umbo", (Schalkwijk-Barendsen), 1-4cm across, convex to flat-depressed; pecan brown to orange-cinnamon; "margin conspicuously ribbed, dry and fibrillose, becoming appressed-squamulose", (Smith)

Flesh:
solid, confluent in cap and stem; white, (Schalkwijk-Barendsen)

Gills:
sinuate, distant, with subgills, sometimes forked near stem; bone colored; serrate, (Schalkwijk-Barendsen), close, broad; whitish then dingy tan, (Smith)

Stem:
up to 3cm tall and 0.3cm wide, whitish; lined at top, base with small scales, (Schalkwijk-Barendsen), 1-3cm x 0.3-0.6cm, solid; pallid [whitish] near top, pinkish tan near base; fibrillose, "scaly near base from lacerated cuticle", (Smith)

Veil:
[absent]

Microscopic spores:
spores 11-16(20) x 5-7 microns, bean-shaped in side view, [presumably narrowly elliptic or oblong in face view]; pleurocystidia and cheilocystidia 60-90(110) x 7-9 microns, subcylindric, (Smith), monomitic; no clamp connections, (Redhead(22))

Spore deposit:
white (Schalkwijk-Barendsen), orange buff (Smith)

Notes:
Heliocybe sulcata was reported from BC by Schalkwijk-Barendsen. The distribution includes AB, MB, ON, SK, YT, AZ, CO, IN, KS, KY, MI, MT, NE, NM, NY, WY, Mexico, Nicaragua, Peru, Italy, Poland, and South Africa, (Redhead(6)). The holotype is from OH (Redhead(22)).

EDIBILITY

Synonyms and Alternate Names:
Lentinus sulcatus Berkeley