Details about map content are available here Click on the map dots to view record details.
Species Information
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.).
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.
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)
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))
Habitat / Range
single or scattered to gregarious in mixed woods and under conifers, (Arora), gregarious under conifers, (Ovrebo(2)), late summer and fall, in California into winter, (Miller)
Similar Species
Tricholoma portentosum has a viscid cap (Arora). T. portentosum has mild taste, has a darker gray or violet-gray cap that lacks an acute umbo, "and often develops yellowish flushes on the gills and stem", (Bessette(5)). Tricholoma argenteum has a lighter colored cap with a rounded to subacute umbo, and is at most slightly virgate, (Bessette(5)). Tricholoma terreum group is similar but in Tricholoma virgatum fibrils and scales are radially arranged, (Arora). An unpublished taxon described from Idaho in Ovrebo''s master''s thesis called T. nigrocystidium nom. prov. is similar but has a viscid cap and a farinaceous odor and taste. Kris Shanks (informal comment on Pacific Northwest key) found something similar in California. The following is derived from Ovrebo''s description: CAP 3-7cm across, conic becoming convex or broadly conic; "neutral gray", "blackish brown", lightening toward margin; viscid, bald, blackish-virgate, FLESH white to pallid, GILLS sinuate, emarginate, close, many tiers of subgills, white, pallid, or colored as stem, STEM 3-8cm x 0.5-1.5cm, equal or widening downward, solid; white to pallid, occasionally yellowing near base; appressed silky-fibrillose with scattered fibrils projecting, ODOR and TASTE farinaceous, HABITAT gregarious under conifers, fall, MICROSCOPIC spores 6-7.5 x 3.8-4.5 microns, ovate, smooth; basidia 33-38.5(41.3) x 7.5-8.3 microns, clavate; pleurocystidia none, cheilocystidia up to 37.5 x 12 microns, clavate, spheropedunculate, colorless in KOH, yellow in Melzer''s reagent; cap cuticle a gelatinous matrix, hyphae 2.3-3.8 microns wide, smooth, colorless to yellowish in KOH, yellow to light brownish in Melzer''s reagent; no clamp connections, (Ovrebo(4)). See also SIMILAR section of Hygrophorus acutus, Tricholoma acre, Tricholoma davisiae, and Tricholoma pardinum.
