Summary:
Features include 1) a hispid-squarrose cap that is dark brown, dry, and generally not cracked, 2) narrowly adnate to notched, pale to brown gills with pallid fringed edges, 3) a woolly, squamulose stem, 4) a mild odor, 5) growth on rotten conifer wood or less often on the ground, 6) nodulose spores, and 7) absent pleurocystidia. Inocybe leptophylla is indistinguishable in the field from I. lanuginosa: identification must be made microscopically (see SIMILAR). Inocybe squarrulosa (P. Karst.) Sacc. may be the same species as I. leptophylla G.F. Atk. and if so, the name of the former would have nomenclatural priority. The description here is derived from Matheny(1) since the differentiation from similar species is made most accurately in that reference. Both Inocybe lanuginosa and I. leptophylla are fairly common in the Pacific Northwest, "with the former occurring more frequently west of the Cascade crest and the latter more frequently on the east side", (Trudell(4)).

Cap:
up to 3cm wide, obtusely conic to flat-convex, "without an umbo, margin slightly incurved when very young, to decurved, arched slightly with age"; dark brown to very dark brown; dry, densely hispid-squarrose on the disc and toward margin, or with recurved fine scales toward margin, "coarsely-fibrillose on decurved portion of the margin", not rimose [not cracked]

Flesh:
thick, up to 0.5cm thick, firm; white, unchanging where bruised, in stem firm, pallid, cortex brownish in lower part

Gills:
narrowly adnate to sinuate or uncinate, close, with several tiers of subgills, rounded toward stem, becoming ventricose, up to 0.4cm broad; light brown with flesh tone or "avellaneous" when young, to pale brown and brown or "cinnamon-brown" to "snuff brown" with age, edges pallid; edges fimbriate [fringed]

Stem:
2-5.5cm x 0.3-0.6cm, equal or tapering somewhat towards base, round in cross-section, solid; pallid at top, colored like cap in lower part, the coating occasionally separating to reveal pallid flesh beneath; white pruinose at top, "appressed-(sub)squamulose to floccose or wooly-fibrillose" in lower part

Veil:
cortina fugacious [fleeting]

Odor:
not remarkable

Taste:
not remarkable or slightly acidulous

Microscopic spores:
spores (8)9.0-12.0(12.5) x (6)7-9(9.5) microns, distinctly elliptic in outline, nodulose, with (9)10-16(18) nodules; basidia 4-spored, (22)24-35(38) microns, clavate, colorless to pale ochraceous; pleurocystidia absent, cheilocystidia abundant, gill edge sterile, (19)29-53(61) microns, "utriform to cylindric, sublageniform or fusiform, apices well-rounded to subcapitate, occasionally crystalliferous but usually bare, thin-walled, hyaline", paracystidia "smaller, clavate to vesiculose, thin-walled, hyaline"; gill trama "regular, compact, hyphae cylindric to inflated", up to 17 microns wide; cap cuticle "a trichoderm of subcylindric to fusiform hyphae, faintly incrusted, brown, with walls up to 1.5 microns thick, end cells undifferentiated", cap trama hyphae parallel to somewhat interwoven, colorless to pale yellow; caulocystidia "restricted to the (extreme) apex, similar to cheilocystidia in shape but also (sub)cylindric, intermixed with cauloparacystidia, hyphae of the stipe vestiture thin- to slightly thick-walled, brown, incrusting pigments faint to not evident"

Spore deposit:
"ochraceous-buff", brown

Notes:
Inocybe leptophylla collections were examined from BC, WA, OR, ID, AB, MB, NB, NS, NT, ON, QC, CA, CO, MI, MT, NH, NY, PA, UT, WY, Mexico, Greenland, Austria, Finland, Germany, Norway, Sweden, and Switzerland, and it is reported also from Asia, (Matheny).

EDIBILITY

Synonyms and Alternate Names:
Inocybe casimiri Velen.