Summary:
Clade Heterophyllidia I. Russula brunneola is characterized by 1) small to medium size, 2) a dark yellow-brown to dark grayish brown or dark olive-brown cap that is viscid when moist, the cap skin separable, 3) mild-tasting flesh, 4) gills that are typically forked and anastomosed, 5) a white stem that may be tinged other colors, and 6) white spore deposit.

Cap:
up to 10cm across, convex-umbilicate, then flat to depressed, margin involute [inrolled]; varying from "Vandyke brown" to "brownish drab" or "burnt umber", sometimes tinged with vinous-purple, rarely with olive-brown, paler when mature; "viscid when moist, the cuticle separable on the margin, pruinose when young", bald, margin soon striate-tuberculate, (Burlingham), 5-12cm across, somewhat spherical then soon almost flat; "deep sepia brown, gray-brown to olive brown, sometimes with paler, yellowish areas; smooth, dry, often pruinose when young", margin finely tuberculate-striate, (Phillips), 5.5-11.5cm across, nearly round when young, expanding to pulvinate [cushion-shaped] or convex with depressed disc, eventually flat-convex with depressed disc, with margin raised and sometimes wavy when old; when young dark grayish brown to dark yellowish brown or dark olive brown, and sometimes with yellowish white to pale orange yellow areas on disc, when mature these same colors to moderate brown, grayish brown, moderate yellowish brown, grayish yellowish brown, or grayish reddish brown centrally and sometimes suffused with pale orange yellow on disc, and dark to moderate yellowish brown, grayish brown, or light olive brown marginally, at times fading when old to light yellowish brown centrally and light grayish olive to pale grayish yellow marginally; viscid when moist, becoming dry, sometimes pruinose at first, becoming bald at least marginally, sometimes radially wrinkled centrally or outward from disc, at times areolate [cracked like dried mud] when old, cuticle thin, separable 1/2-2/3 the cap radius, becoming finely striate or tuberculate-striate 0.2-1.2cm from edge, (Shaffer)

Flesh:
rather firm; tinged with brownish or slate-violet under the cuticle, otherwise white, (Burlingham), firm; white, (Phillips), 0.5-1.1cm thick in disc, firm-brittle when young, becoming softer when old; sometimes tinged cap color near surface, otherwise yellowish white, light to dark yellow around the larval channels, "unchanging when cut or becoming pale yellow to grayish yellow", (Shaffer)

Gills:
close, rather broad, "equal, acute at the inner ends, rounded at the outer", forking near the stem or a little distance away, venose-connected; white, becoming yellowish in drying, the edges sometimes tinged with "Vandyke brown"; pruinose, (Burlingham), "moderately crowded, broad, prominently forking near stem; pale cream to slightly brownish", (Phillips), adnate to adnexed, close to subdistant, 0.4-0.9cm broad, equal, subacute to acute near margin, elastic, prominently forked-anastomosed-crisped near stem; "white when young, becoming yellowish white to pale yellowish green", rarely tinged dark grayish red near cap margin, sometimes spotted-stained dark yellowish brown to dark olive brown when old, but unchanging when injured; interveined, entire, (Shaffer)

Stem:
4-6cm x 1.5-2cm, nearly equal, spongy; white to tinged with slate-violet; bald, (Burlingham), 4-8cm x 1-3cm, "equal, firm; yellowish white or flushed pale purple to reddish brown at base; dry, dull", (Phillips), 4-8cm x 0.9-2.7cm, equal, fusiform [spindle-shaped], or flared at top and widening or narrowing at base, solid at first, becoming stuffed and sometimes hollow; "yellowish white overall or partly purplish white to light reddish brown, often spotted-stained moderate yellow to moderate yellowish brown basally, but unchanging or at most becoming grayish yellow when bruised"; dry, dull, bald, longitudinally wrinkled, (Shaffer)

Odor:
none (Burlingham), pleasant (Phillips), nondescript (Shaffer)

Taste:
mild (Burlingham, Phillips), nondescript (Shaffer), mild, sometimes nutty, (Roberts, C.)

Microscopic spores:
spores 6-8 x 5-6 microns, round to elliptic, very minutely echinulate [spiny], (Burlingham), spores 6-9.5 x 4-7.5 microns, warts up to 0.7 microns high, mostly isolated, occasionally a few fine connectives, (Phillips), 6.0-9.6(11.4) x 4.1-7.1 microns (or in some collections rare giant spores up to 15.0 x 7.8 microns), elliptic, ovate, or obovate, at times even nearly round, ornamentation "of blunt, convex to conic or cylindric warts" mostly up to 0.2-0.7 microns high, but in some collections 1-few apical warts up to 1.2 microns high, the warts mostly isolated, sometimes aligned, clustered, or rarely with connectives, usually not forming a reticulum; basidia 29-45 x 6.1-11.3 microns, narrowly clavate, usually 4-spored, occasionally 2-spored; hymenial pseudocystidia common to abundant, 34-107 x 5.3-11.3 microns, "fusiform, fusoid-clavate, or fusoid-ventricose", "often capitate or appendiculate (sometimes moniliform-appendiculate), otherwise rounded to subacute apically", arising usually in subhymenium, occasionally in outer trama, projecting up to 40 microns beyond basidioles, cheiloleptocystidia common in places, 12-30 x 3.8-8.6 microns, subcylindric, clavate or fusiform, colorless, (Shaffer), pileocystidia absent, (Thiers)

Spore deposit:
white (Burlingham), white to palest cream, Crawshay A-B, (Phillips), white to yellowish white, (Shaffer), white, Crawshay A or very slightly off A, never reaching B, (Singer)

Notes:
It has been found in WA (Phillips, Shaffer), ON, MA, MI, and VT, (Shaffer), MA, NH, and VT (Burlingham), NC, VA, VT, and WV, (Bills), and CA (Thiers). It is found on Vancouver Island in BC (Roberts, C.(2)).

EDIBILITY

yes, good, (Phillips)