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Species Information
Summary: Tricholoma pardinum is characterized by a dry cap that is whitish with small, regularly spaced, pale gray to dark gray, fibrillose or spot-like scales. It is distinguished from other dry, grayish Tricholomas by its larger fleshier stature and often paler color. Microscopic characters include relatively large spores, and the presence of cheilocystidia and abundant clamp connections. |Three Pacific Northwest collections identified as Tricholoma pardinum all matched more closely the DNA of Tricholoma huronense instead, (D. Miller, pers. comm.).
Collections were examined from WA, OR, and CA, (Smith(48)). Arora says it is widely distributed in northern North America and sometimes abundant under conifers in the Pacific Northwest and Rocky Mountains. Shanks describes for CA. There are collections from BC at the Pacific Forestry Centre and the University of British Columbia and collections from ID and OR at Oregon State University. Bessette(5) includes CO in the distribution. Ovrebo examined collections from ON, MI, and MN.
Cap: 5-16(25)cm across, convex to flat; "whitish with small pale gray to dark gray fibrillose or spotlike scales, at least at center"; dry, (Arora), 3-11.5cm across, convex to flat, margin remaining downturned when old; "dry, with uniformly scattered small dark grayish brown to black, appressed or recurved squamules and occasional fibrils over a white to pale gray background, the margin occasionally white", (Shanks), 2-15cm across, convex to obtuse, expanding to nearly flat and often with obtuse or conic umbo; "dark drab or hair brown when young, when mature drab gray to gray brown overall or with the disc fuscous, dingy brown or yellowish brown and the margin somewhat lighter, the color due to drab to brownish black fibrils or squamules against a lighter, grayish buff ground color"; dry, "matted-fibrillose or occasionally areolate-squamulose over center, elsewhere with a combination of appressed to recurved fibrils or squamules", (Ovrebo)
Flesh: thick, firm; white, (Arora), white to pale gray, in stem white, occasionally orange-white in the base, (Shanks), firm; white to light gray, unchanging when cut, (Ovrebo), grayish white in cap, yellowish at base of stem, (Lincoff)
Gills: "notched or adnexed, close"; "white (rarely flushed pinkish), not stained or spotted gray", (Arora), sinuate to deeply notched, close to subdistant, 0.8-1.2cm broad, somewhat thick; whitish to cream or yellowish white, (Shanks), adnate-decurrent on buttons, sinuate when mature, close, up to 1cm broad, edges bluntly rounded when young; pallid to grayish buff, "unchanging or discoloring dingy brown where bruised", generally becoming brownish on edge when old, (Ovrebo), edges eroded when old (Ammirati(11)), 100-116 reaching stem, 1-2 tiers of subgills; "creamy to white or merely pallid, at times flushed pale pinkish or occasionally discoloring slightly to grayish when bruised", (Smith)
Stem: 4-15cm x 1.5-3cm, equal or widened in lower part, firm, solid; white or sometimes tinged gray; smooth, (Arora), 7-11cm x 0.7-2.5cm, "equal, the base slightly bulbous or tapered", solid, very firm; at top white or colored as gills, "the surface fibrils of the lower half bruising pale brown to golden tan"; dry, silky-fibrillose, (Shanks), 2.5-12cm x 1-2cm, equal or slightly club-shaped, the base occasionally slightly bulbous; whitish buff, becoming dingy brown when old or where handled; "silky-fibrillose, occasionally with inconspicuously appressed squamules, often lacerate-scaly in age from a broken cuticle", (Ovrebo), white, unchanging or becoming dingy brown toward base when old, (Ammirati), base stains more or less yellow or rusty, (Leuthy)
Microscopic spores: spores 7-10 x 5-6.5 microns, elliptic, smooth, (Arora), spores 6.2-10.6 x 4.3-6.7 microns, elliptic to broadly elliptic, smooth, inamyloid, colorless; basidia 4-spored, 38-48 x 7.2-9.6 microns, nearly cylindric to slightly clavate, colorless; cheilocystidia scattered to abundant, 24-58 x 12-19 microns, broadly clavate to spheropedunculate, colorless, smooth, thin-walled, easily collapsing; clamp connections scattered throughout, (Shanks), spores 8.6-9.5 x 5.7-6.7 microns, elliptic in face and side view, smooth, inamyloid, thin-walled; basidia 4-spored, 38-45 x 8.6-9.5 microns, clavate, colorless; cheilocystidia 29-41 x 12-21 microns, clavate to spheropedunculate, smooth, thin-walled, clear or granular, colorless; clamp connections present on most hyphal cross-walls throughout the fruitbody, (Ovrebo)
Spore deposit: white (Arora)
Habitat / Range
single to scattered or gregarious on ground in woods, under conifers or hardwoods (including at least tanoak, madrone), (Arora), scattered to gregarious with conifers or in mixed woods, September to December, (Shanks), gregarious or cespitose [in tufts] under conifers, (Ovrebo), usually fruiting in fall, but up to January, (Miller), fall, winter
Similar Species
Other large grayish Tricholoma like Tricholoma virgatum, Tricholoma nigrum, and Tricholoma huronense have "more evenly colored, smooth or streaked rather than scaly-spotted caps", (Bessette(5)). The grayish to brownish species typified by Tricholoma terreum "are smaller and their often more densely wooly or scaly caps are more evenly colored and often have a felt-like appearance", (Bessette(5)). T. terreum and T. virgatum can be somewhat similar but T. pardinum is larger and fleshier and often paler, and can be nearly white with a few very pale grayish scales, (Arora). Tricholoma saponaceum lacks fibrillose scales on its cap (although the cap may crack into scales) and usually has pinkish flesh in stem, (Arora). Tricholoma venenatum "is pale tan or buff overall, and the cap scales appear more brownish than blackish", (Bessette(5)). Ovrebo makes the following comparison of T. pardinum, T. venenatum, and T. huronense: T. pardinum gray to grayish brown cap, conifers, cheilocystidia, T. venenatum buff to tan cap, hardwoods, no cheilocystidia, and T. huronense smoky gray cap often streaked with pink on margin, hardwoods, cheilocystidia, (Ovrebo(5)), but 1) Shanks(2) says T. venenatum is associated with conifers in California, 2) Arora says T. pardinum is associated with live oak and madrone in California, and 3) there is a lighter form of T. pardinum with cheilocystidia that are collapsed and difficult to find which makes it difficult to distinguish from T. venenatum.
