Summary:
Tricholoma vaccinum is characterized by 1) a dry cap with radial reddish brown fibrils or scales that separate to reveal the buff background, 2) adnate to notched, whitish or buff gills that discolor or spot brownish, 3) a stem that is often hollow and often has brown fine scales, 4) a woolly veil that normally leaves hairs on the cap margin, 5) a usually farinaceous odor, and 6) an association with conifers. Preliminary DNA evidence supports the presence of the European taxon on the west coast of North America, (D. Miller, pers. comm.).

Cap:
4-7(10)cm across, broadly conic to convex, becoming umbonate or flat, margin often splitting when old; covered with dark reddish brown to rusty cinnamon brown to pale pinkish brown, tan or flesh-colored fibrils or scales on a buff background, often darker at center; dry, "margin with hairy veil remnants at least when young", (Arora), 2-7cm across, conic to convex becoming broadly convex to flat-convex when old, often with rounded or subacute umbo, margin inrolled at first becoming downturned; rusty brown, disc often darker; dry, matted-fibrillose overall with occasional recurved squamulose [fine scales] near margin when young, becoming matted-fibrillose to rimose-areolate [cracked like dried mud] over disc, the rest with various combinations of recurved to appressed fibrils, squamules and scales, occasionally rimose-areolate overall, frequently with radiating cracks at margin, margin cottony or with appendiculate [hanging] fibrils at first, (Shanks), 2-7cm across, medium rusty tan or rusty brown overall, the center often darker brown or sometimes overall, occasionally light tan or cinnamon overall, the color being in the fibrils and scales, the buff ground color generally exposed between, (Ovrebo)

Flesh:
white or pallid (Arora), whitish in cap and stem, (Shanks), 0.5-0.7cm thick, buff, often light brown below cap surface or watery gray above gills, in stem light buff, (Ovrebo)

Gills:
"adnate becoming notched, close"; "whitish or buff when young, but usually tinged flesh-color to pale cinnamon in age", "sometimes also with darker stains", (Arora), adnate to deeply notched, close to subdistant; cream or pale buff at first, spotting brownish orange, and becoming orange buff overall when old, (Shanks), "arcuate when young, when mature emarginate to sinuate, rarely adnate or subdecurrent", close, subgills numerous but not arranged in distinct tiers, gills 0.2-0.8cm broad; whitish buff, becoming very light cinnamon overall in extreme age, discoloring yellowish brown on edge and/or in spots on face; edges entire, (Ovrebo)

Stem:
3-8cm x 0.8-1.5cm, equal or wider at either end, usually hollow at least when old; "dry, smooth or with brownish to reddish-brown fibrils or small scales", (Arora), 3-8.5cm x 0.4-2cm, equal, occasionally club-shaped, stem hollow; dry, pruinose at top, silky fibrillose, lower two thirds with belts of brown squamules [fine scales] over buff ground at first, when old fine scales present or absent, (Shanks), 3-8cm x 0.6-2.2cm, equal or occasionally club-shaped or reverse club-shaped, the base rounded or abruptly tapered, stem hollow or rarely solid; when young light buff overall or with brown fine scales against buff ground color, when mature light buff at top. the lower part either with fine brown scales or if fine scales absent becoming brownish buff to rusty brown; "dry, silky-fibrillose, often roughened with loosened surface fibrils", with recurved fine scales present or not, the top often pruinose, (Ovrebo), often spindle-shaped and hollow, (Trudell)

Veil:
woolly-fibrillose, not forming ring on stem but usually leaving traces on cap margin, (Arora), cortinate partial veil, (Shanks), a cortina of light brown fibrils (sometimes scarcely visible even on buttons), remnants also hanging from cap at first, no traces remaining on stem, (Ovrebo)

Odor:
"usually farinaceous but sometimes mild", (Arora), not distinguishable, (Shanks), nondescript to farinaceous, (Ovrebo), farinaceous (Phillips), unpleasant (Miller)

Taste:
not distinguishable (Shanks), nondescript to farinaceous, (Ovrebo), bitter (Phillips), unpleasant and bitter (Miller)

Microscopic spores:
spores (4)6-7.5 x 4-5 microns, elliptic, smooth, inamyloid, (Arora), spores 6.2-7.2 x 4.3-5.3 microns, elliptic; basidia 4-spored, rarely 2-spored, 28-36 x 6.2-7.2 microns, clavate; pleurocystidia and cheilocystidia absent; clamp connections absent, (Shanks), spores 6.2-7.6 x 4.3-5.2 microns, (Ovrebo)

Spore deposit:
white (Arora)

Notes:
Ovrebo examined collections for NS, ON, CO, ME, MI, MN, NY, and VT. It has been reported from WA by O''Dell(1). There are collections at the Pacific Forestry Centre for BC, at Oregon State University for AK, BC, and OR, at the University of Washington for AK and WA, and at the New York Botanical Garden for ID. Arora(1) mentions it for OR and CA. It has been reported by Kernaghan(1) from AB, and Bigelow for NT (Ft. Smith). Bessette(5) say it is widely distributed in northern N. America "and extending southward in mountain ranges such as the Appalachians and Rockies" and they show photographs from WA, AK, AZ, and CO.

EDIBILITY

considered mildly poisonous by some authors (Arora)