Summary:
{See also Viscid Gray-brown Lactarius Table.} Features include 1) a slimy-viscid, blackish brown cap, 2) white milk that slowly stains tissues olive-brown or gray-brown, 3) close gills that are pale pinky-buff to pale ochreous salmon flushed cinnamon and stain light brown, 4) a slimy-viscid stem that is pale pinky-brown or tan, 5) a peppery taste, 6) whitish spore deposit, and 7) elliptic to nearly round spores with amyloid ridges and rare isolated warts. Hesler(4) say that it is distinguished by a dark to blackish brown slimy cap, slimy +/- vinaceous to tan stem, more or less pale vinaceous gills when young staining olive to gray and finally brown, large size, and white to off-white color of the spore deposit. Var. sitchensis has a dark brown cap that soon develops dingy yellow-brown tones, has a distinctly thinner cap than the type, and has spores that are yellow in mass: it was described by Hesler and Smith from OR and is known only from the type collection. Lactarius kauffmanii var. kauffmanii is common in the Pacific Northwest.

Cap:
5-15cm across, flatly convex with a depressed cap center and inrolled margin that is uplifted when old; "blackish brown becoming more reddish gray-black, and very occasionally with concentric bands of color"; slimy and sticky [viscid], "smooth, sometimes streaked under the slime", (Phillips), 5-15(20)cm across, broadly convex with depressed disc, margin inrolled at first, elevated when old; blackish brown becoming drab to grayish or grayish vinaceous when old, without zones or more rarely with obscure zones; slimy-viscid, bald, sometimes virgate [radially streaked] under the slime, margin pubescent [minutely hairy] when very young, (Hesler), 5-15(30)cm across, brown to dark brown, not zoned; bald, viscid to glutinous, fibrillose-streaked, (Methven)

Flesh:
violet-brown near the cap surface, pale pinky-brown near the gills, (Phillips), violaceous-brown near cap surface, "pale vinaceous-fawn" near gills, (Hesler), 1-1.5cm thick at disc; white to orange-white, unstaining on exposure, (Methven), MILK white, unchanging, slowly staining gills olive-brown or gray-brown, (Phillips), white, slowly staining gills olivaceous to grayish brown, (Hesler(4) who say that milk is unchanging but also say that in the group of collections chosen as type, the milk changes to olive or stains tissue olive to olive brown, and that variants exist in which brown stains may develop in a short time without an intervening olive tone), copious; white, slowly staining the gills light brown, drying gray green, (Methven)

Gills:
"adnate to short decurrent, close, narrow becoming broad, forking near the stem; pale pinky-buff to pale ochraceous salmon flushed cinnamon or with brown patches", (Phillips), adnate to short-decurrent, close, narrow becoming broad, forking near stem; ''pallid becoming flushed pale dull vinaceous to "pale ochraceous-salmon," in age flushed "pale pinkish cinnamon" or darker and often with brown stains as well as those from latex which may eventually become brown'', (Hesler), "adnate to subdecurrent, close to subdistant, broad", forking near stem; pale orange to light orange, staining light brown where cut, edges colored as faces, (Methven)

Stem:
5-10cm x 1-3cm, becoming hollow, sometimes wider in the middle; pale pinky-brown or tan; slimy, sticky [viscid] and shiny, smooth, pitted, (Phillips), 5-10cm x 1-3cm, often wider in mid-portion, soon hollow; pallid to vinaceous-cinnamon or tan [also called ''pale vinaceous-cinnamon to pale vinaceous-tan'']; "slimy-viscid, appearing varnished in dry weather", bald, "often uneven but characteristically scrobiculate", (Hesler), 4-12cm x 1-3cm, equal or narrowed toward base, round in cross-section, hollow; light orange to grayish orange; bald, subviscid to viscid, scrobiculate, (Methven), "light grayish orange or tan to vinaceous cinnamon", (Trudell)

Veil:
[none]

Odor:
none (Phillips), not distinctive (Methven)

Taste:
peppery (Phillips, Hesler), slowly peppery (Methven)

Microscopic spores:
spores 9-9.5 x 7.5-8.5 microns, nearly round to ovate, amyloid, "ornamented with a distinct partial reticulum with irregular meshing", prominences 0.2-0.7 microns high, (Phillips), spores 7-11 x 6-9 microns, broadly elliptic, "ornamentation in the form of a distinct partial reticulum with the netting quite irregular as to the shape of the meshes, many elongated ridges present, isolated warts generally rare", prominences 0.2-0.7(1.0) microns high; basidia 4-spored, 40-50 x 9-12 microns; pleurocystidia: macrocystidia 60-100 x 9-12 microns, "fusoid-ventricose with acute apex to subaciculate, content granular", pseudocystidia not observed, cheilocystidia "present but remaining collapsed (about as for the macrocystidia but smaller)"; cap cuticle an ixotrichoderm arising from a basal zone about 75 microns deep of narrow repent hyphae, the slime KOH-stable; stem cuticle a distinct ixolattice collapsing to an ixocutis, slime KOH-stable, (Hesler), spores 8-9.5 x 6-7.5 microns, broadly elliptic to elliptic, amyloid ornamentation a partial reticulum 0.5-1 micron high; basidia 35-55 x 7.5-10.5 microns, macrocystidia 70-95(110) x 7.5-10.5 microns, fusoid-ventricose to aciculate, cheilocystidia 35-55 x 4.5-7.5 microns, "fusoid-ventricose to aciculate, at times with subapical constrictions"; cap cuticle "an ixotrichodermium arising from an interwoven layer of filamentous hyphae, dextrinoid debris and incrustations present"; stem cuticle an ixolattice collapsing into an ixocutis, (Methven)

Spore deposit:
whitish (Phillips), varies from white to off-white to "pale pinkish buff" (almost white), in at least some instances if it is weakly yellowish at first, it becomes whitish on drying out, (Hesler), white in mass (Methven)

Notes:
Collections of L. kauffmanii var. kauffmanii were examined from BC, WA, OR, ID, CA, MI, and WI, (Hesler(4)).

EDIBILITY

no (Phillips)