Tricholoma atroviolaceum
no common name
Tricholomataceae

Species account author: Ian Gibson.
Extracted from Matchmaker: Mushrooms of the Pacific Northwest.

Introduction to the Macrofungi

Photograph

© Kit Scates-Barnhart     (Photo ID #19040)


Map

E-Flora BC Static Map

Distribution of Tricholoma atroviolaceum
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Species Information

Summary:
Features include 1) large size, 2) a dry cap that is blackish violet to grayish violet brown, and densely fibrillose-scaly, 3) sinuate to adnexed, close, gray-brown gills, typically staining blackish on the edges, 4) a thick sometimes abruptly bulbous stem that is brownish with scattered fine scales, darkening to violaceous brown, 5) a farinaceous odor and taste, 6) growth under conifers, 7) a whitish spore deposit, and 8) microscopic characters. Shanks(2) adds also that 9) the texture is hard in the stem and 10) the cap flesh and stem flesh stain rapidly reddish gray and finally grayish brown.
Cap:
5-12(14)cm across, "obtuse and with a slightly incurved margin when young", becoming broadly umbonate or flat, the margin spreading or recurved somewhat when old and often plicate [pleated] or splitting radially; blackish violet from the dense covering of fibrils, ("dark grayish brown" over central part and "benzo brown" along margin, darker when old); dry, covered overall except on margin by minute, recurved, blackish violet scales, (Smith(17)), 4-10cm across, broadly convex to flat, the margin often wavy and uplifted when old; nearly black over disc, grayish violet brown to violet gray at margin, fading to grayish brown overall when old; matted-fibrillose over disc, "appressed-fibrillose to squamulose elsewhere", (Shanks)
Flesh:
thin but rigid and brittle, 0.4-0.5cm thick near stem; sordid brownish gray to nearly "drab-gray", "no color change when cut or bruised but sometimes gradually darkening", in stem tinged pale drab, (Smith(17)), thin; 'whitish at first, rapidly bruising reddish gray and finally sordid grayish brown', in stem staining like cap flesh, "base often with yellow or tan coloration", (Shanks), cap flesh often stains reddish gray when cut (Trudell)
Gills:
sinuate to adnexed, close, 1-2 tiers of subgills, broad, up to about 1cm broad, very brittle; dull cinnamon overcast with gray ("light cinnamon-drab", "light drab" or "wood-brown"), edges usually staining blackish; edges uneven to eroded, (Smith(17)), sinuate, close, 0.8-1.5cm broad, thick, anastomosing in some caps; very pale gray when young, becoming sordid brownish gray when mature, margins discoloring fuscous at times, (Shanks)
Stem:
6-14cm x 1-3cm, equal to widened in upper part or sometimes with abruptly bulbous base, stem solid; pallid at first but soon tinged "benzo brown" and finally quite dark; appressed-fibrillose and "becoming somewhat furfuraceous at times from the broken cuticle", (Smith(17)), 5-10cm x 1.5-4cm, "equal, base abrupt or tapered", solid, tough; whitish to pale violet gray, developing yellowish tan colors toward base or where handled; "dry, dull appressed-fibrillose with some surface fibrils projecting", pruinose at top, (Shanks)
Odor:
very strongly farinaceous (Smith(17)), "strongly rancid farinaceous to mildly farinaceous", (Shanks)
Taste:
slightly to strongly farinaceous, (Smith(17)), farinaceous (Shanks), somewhat bitter (Trudell)
Microscopic spores:
spores 7-9 x 4.5-6 microns, subelliptic to suboval, inamyloid; basidia 4-spored, pleurocystidia and cheilocystidia not differentiated, (Smith), spores 7.2-10 x 4.8-7.2 microns, elliptic to broadly elliptic, smooth, inamyloid, colorless; basidia 4-spored (occasionally 2-spored), 43-56 x 8.6-12 microns, clavate, occasionally mucronate, colorless, some basidioles fuscous near gill margins; pleurocystidia and cheilocystidia absent; cap cuticle a cutis, hyphae 4.8-14 microns wide, "forming recurved fascicles, brown, thick-walled and smooth, or with rough brown encrustations"; hyphae of the pseudoparenchymatous hypoderm 9.6-24(50) microns in diameter, inflated to nearly isodiametric, colorless and smooth, or with plaques of dark brown encrustations, thin-walled to thick-walled; clamp connections absent (Shanks)
Spore deposit:
[presumably whitish]
Notes:
Material was examined from OR (including holotype) and WA (Smith(17)). It was included for CA by Shanks(2). There is a collection for BC at the Pacific Forestry Centre and others at the University of British Columbia. Bessette(5) shows a photograph from ID.
EDIBILITY

Habitat and Range

SIMILAR SPECIES
Tricholoma atrosquamosum has white to very pale gray gills, and lacks the pseudoparenchymatous hypodermium, (Shanks). Tricholoma atrosquamosum is usually smaller, "its cap margin is inrolled and distinctly bearded when young, it lacks violet tones, its flesh does not stain reddish gray when cut, and it lacks a pseudoparenchymatous hypodermium", (Bessette(5)). Tricholoma luteomaculosum lacks violet tones on the cap and has cheilocystidia and pleurocystidia, (Shanks). T. luteomaculosum has a cap that lacks violet tones and is more appressed-fibrillose, it sometimes develops dingy yellow stains on the cap margin and gills, and it has cystidia, (Bessette(5)). Tricholoma acre has a slightly smaller (cap 3-9cm) that is grayish fibrillose, white to grayish gills, and a distinctly peppery taste, (Arora, but note that Ovrebo(2) gives taste of T. acre as bitter). Tricholoma orirubens has a white stem, and slowly develops reddish stains on the gills and stem, (Bessette(5)). T. orirubens also has shorter spores. See also SIMILAR section of Tricholoma atrosquamosum var. atrosquamosum and Tricholoma nigrum.
Habitat
under conifers (Smith(17)), single to scattered under conifers, September to December, (Shanks for California), fall, winter