Under N. menziesii. Nelson: Karamea, Umere, 29.xii.l969, R. F. R. McN.; 4.i.l970, A. Y. McN. (holotype, PDD 30626).

pileus: 6-10 cm diam., plano-convex to centrally depressed at maturity, viscid, glabrous, innately subpruinose under lens, velar remnants absent, probably pallid when young, mid brown, dark brown, greyish brown, or dark brownish grey at maturity, blackening when overmature: margins entire, thick, moderately involute, non-pectinate. Cuticle 200-250 µm thick, gelatinised at maturity, composed of obliquely ascending, interwoven, thin-walled, septate hyphae 2-4.5 µm diam., often with dark brown contents in KOH, terminal cells unspecialised; pilocystidia rare, embedded, cylindrical with strangulate or capitulate apices, contents refractive in KOH, to 5 µm diam. lamellae: adnate, moderately crowded, thick, simple, to 7 mm deep, dull creamy white with faint greyish tints, heavily discoloured with black spots, blackening with age, lamellulae numerous, in 3 unequal series, typically in sequence. stipe: 4-5 cm long, ± equal or tapering basally, 1.3-2.5 cm diam., dry, solid, subvelutinate under lens, sordid greyish fawn to brownish grey, darker towards base; flesh white at first, rapidly blackening on exposure to air. Cuticle composed of a palisade of thin-walled, septate hyphae 3-4.5 µm diam., often with dark brown contents in KOH, terminal cells unspecialised; caulocystidia rare, embedded, similar to pilocystidia. spores: spore print not obtained; spores broadly elliptical, obliquely apiculate, apiculus to 1.5 µm long, 7.5-9 X 6.5-8 µm, ornamentation of amyloid verrucae and crests to 0.5 µm high, joined by fine amyloid ridges and forming a complete or almost complete reticulum; plage absent. hymenium: basidia tinted, clavate, 47-60 X 9-11.5 µm, 4-spored, sterigmata to 7 µm long; pleurocystidia scattered, numerous, narrow fusiform, thin-walled, contents refractive in KOH, projecting to 20 µm beyond basidia, apices acuminate, capitulate, or strangulate, 65-100 X 5.5-8 µm, cheilocystidia similar to pleurocystidia but shorter. hymenophoral trama: heteromerous, intermixed, oleiferous hyphae present. context of pileus: white, rapidly blackening on exposure to air, firm, rather granular; structure heteromerous, clamp connections absent. taste: lamellae and context acrid. chemical characters: FeSO4 on context— greyish green; KOH on pileus—faint darkening; on context— faintly yellow; NH4OH on pileus and context—n.r.

Solitary or in pairs under Nothofagus.

Pileus plano-convexus ad centraliter depressum 6-10 cm diam., griseo-brunneus, viscidus, glaber; margines integri, crassi, non pectinati. Lamellae adnatae ad 7 mm altae, obscure cremeo-albae, maculis nigris decoloratae; lamellulae numerosae in tribus seriebus inaequalibus. Stipes 4-5 cm longus, basim angustatus, 1.3-2.5 cm diam., siccus, solidus, concolor cum pileo. Sporae late ellipticae 7.5-9 x 6.5-8 µm, amyloides ornatae.

Young fruiting bodies of this species have not been collected, but if .R. inquinata follows the pattern of other species in the subsection, they are probably pallid in colour, darkening with maturity.

The blackening fructifications, firm context, and regularly arranged lamellulae indicate that R. inquinata belongs to section Compactae subsection Nigricantes Bat. as defined by Singer (1962). Russula inquinata is close to R. adusta (Pers. ex Fr.) Fr. but differs in the acrid taste, and the greyish green reaction to FeSO4 Russula adusta is a Northern Hemisphere species restricted to coniferous habitats. It belongs to the Compactae subsection of Russula as defined by Shaffer (1962).

holotype, PDD 30626