Summary:
Tricholoma virgatum is recognized by 1) its dry cap with gray radially arranged fibrillose streaks, the cap shape conic when young, 2) adnexed to notched, close, white to grayish gills, 3) a dry, white to gray-tinged stem, 4) a peppery to bitter taste, and 5) a white spore deposit. |The cucumber odor is caused by trans-2-nonenal, one of the chemicals causing the odor in the cucumber vegetable (Wood). |Ovrebo(1) describe a var. vinaceum that is like T. virgatum except for the pinkish cast on the stem. |Preliminary DNA evidence suggests that what is usually identified as Tricholoma virgatum in the Pacific Northwest is often T. argenteum - five collections identified as T. virgatum all matched T. argenteum instead, (D. Miller, pers. comm.).

Cap:
3-8(10)cm across, conic to broadly conic to nearly flat with a pointed umbo; grayish to grayish brown or grayish purple (center often darker, margin paler); dry, "streaked with radiating fibrils or fibrillose scales", (Arora), 3.5-10cm across, conic to obtuse with acute umbo and slightly incurved margin, expanding to broadly conic, convex-umbonate or flat-umbonate, the umbo acute, occasionally margin uplifted when old; "silvery gray to gray, the disc generally the darkest gray, becoming lighter toward the margin where finally light gray, silvery buff or nearly white on the edge, virgate, the virgate condition caused by the dark gray innate fibrils and is most evident on young carpophores and is least evident on the pileus edge"; dry, bald, with long innate radially arranged fibrils, the fibrils under 10x hand lens generally appearing slightly interwoven, (Ovrebo(2)), "neutral gray", "blackish brown", "dark purplish gray", "sooty black", "drab neutral gray", "Quaker mouse gray", margin lighter, (Ovrebo(1) for var. vinaceum)

Flesh:
thin; white then grayish, (Arora), thin; pale gray, (Ovrebo(2))

Gills:
adnexed or notched, close; white to grayish, (Arora), sinuate, close, 0.4-0.8cm broad, subgills numerous but not arranged in distinct tiers; "whitish to very pale gray, often becoming dingy buff in extreme age, occasionally discoloring fuscous on edge"; entire, (Ovrebo(2)), white or grayish-tinged flesh color, (Phillips)

Stem:
6-12(15)cm x (0.5)1-2cm, more or less equal, solid; white or tinged gray; smooth or fibrillose, (Arora), 6-10cm x 0.9-1.5cm, equal or subclavate [somewhat club-shaped], the base rounded or rarely bulbous, stem solid or hollow; white; silky-fibrillose and with superficial fibrils projecting, (Ovrebo(2)), white, off-white, or very light grayish drab, pinkish or vinaceous drab near base or beginning half way down the stem, (Ovrebo(1) for var. vinaceum), "white or tinged gray; smooth or minutely hairy", (Phillips), white or flushed pink, purplish pink at base, (Leuthy)

Veil:
absent (Arora), cortina present (Leuthy)

Odor:
mild or earthy (Arora), absent (Ovrebo(2), Ovrebo(1)), musty (Phillips), cucumber (Wood)

Taste:
usually sharp or peppery (Arora), peppery to bitter, (Ovrebo(2)), bitter (Ovrebo(1)), bitter and peppery, (Phillips), bitter or peppery (Shanks), resembles being pricked by tiny needles at tip of tongue (differing from Russula or Lactarius), (Lincoff(1))

Microscopic spores:
spores 6-7.5 x 5-6 microns, elliptic, smooth, [presumably inamyloid], (Arora), spores 6-7.5 x 5-6 microns; cheilocystidia 25-45 x 6-15 microns, clavate, sometimes septate, +/- gray incrusted, (Hansen), spores 7.2-8.6 x 5.2-6.2 microns, broadly elliptic in face view and side view, smooth, inamyloid, thin-walled; basidia 4-spored or rarely 2-spored, 31-39(49) x 7.6-9.5(11.4) microns, clavate, colorless; cheilocystidia 28-38 x 10.5-14 microns, "cylindric or clavate, smooth and thin-walled, without content or often granular and then appearing like very large basidioles", colorless, "the walls occasionally slightly refractive"; clamp connections absent, (Ovrebo(2)), spores 7.5-9 x 5.3-6 microns, ovate in face view, broadly elliptic or bean-shaped in side view, smooth, guttulate; basidia 33.8-45 x 7.5-9 microns, clavate, those on gill edge often larger (up to 11.3 microns wide), often guttulate; cheilocystidia 48.8 x 15 microns, clavate or irregularly clavate, smooth, colorless in KOH, inamyloid; clamp connections absent, (Ovrebo(1) for var. vinaceum)

Spore deposit:
white (Arora, Ovrebo(2))

Notes:
Ovrebo(2) 1989 examined collections of Tricholoma virgatum from NS, ON, MA, ME, MI, MN, NY, VT, and Shanks(2) includes it for CA. Collections labeled Tricholoma virgatum from BC are at the Pacific Forestry Centre and the University of British Columbia. The University of Washington has collections from WA, OR, ID, CA, AK, WY, and Finland. Ovrebo(1) described var. vinaceum from WA, OR, and ID, and Kernaghan(1) reported this variety from AB.

EDIBILITY

may be poisonous and resembles poisonous Tricholoma pardinum, (Arora)

Synonyms and Alternate Names:
Melanoleuca subacuta (Peck) Murrill
Tricholoma subacutum Peck