Under (1) N. fusca. Nelson: Oparara River, 211970, R. F. R. McN. (3 coils). (2) N. fusca and N. menziesii. Nelson: Oparara River, 2.1.1970, R. J. McN.; R. F. R. McN.: Maruia 28.iii.l966, R. F. R. McN. (pdd 26931). (3) N. menziesii. Nelson: Karamea,, Umere, 19.i.l968, 2.L1969, 8.1.1969, R. F. R. McN.; 4.i.l970, A. Y. & K. E. McN.; Oparara River, Fenian Track, 9.L1968, R. F. R. McN. (holotype, pdd 30624). (4) N. menziesii and N. truncata. Nelson: Taffytown, IO.V.1971, A. Y. McN. (5) N. solandri, Canterbury: Kowai Bush, 5.ii.1969, B. Segedin; Wellington: Tongariro National Park, Chateau, I.V.1967, A. C. Eden (PDD 26542). (6) Nothofagus sp., Taupo Co: Poronui, 18.iv.l970, J. B. Taylor (PDD 29447).

pileus: 4.5-11 cm diam., hemispherical to convex when young, centrally depressed to infundibuliform at maturity, viscid under wet conditions, glabrous, often faintly creviced or finely rugulose, innately pruinose to finely felted under lens, velar remnants absent, greyish brown, dark greyish brown, or pallid sepia, often with a sooty appearance; margins entire, thick, non-pectinate. Cuticle 150-200 µm thick, partially gelatinised at maturity, composed of obliquely ascending, interwoven hyphae and pilocystidia; hyphae thin-walled, septate, 3.5-6.5 µm diam., with dark brown contents in KOH, terminal cells unspecialised; pilocystidia numerous, ± cylindrical with acuminate, capitulate, or strangulate apices, thin-walled, contents refractive in KOH, 70-120 X 5-9 µm. lamellae: adnate to subdecurrent, crowded, moderately thick, simple or occasionally forked near stipe, to 8 mm deep, pallid creamy white when young, becoming cream to pallid creamy ochraceous, occasionally discoloured in places ,at maturity, lamellulae numerous, in 3 unequal series, typically in sequence. stipe: 3-5 cm long, equal or tapering basally, 1.2-2.5 cm diam., solid, dry, glabrous, faintly pruinose under lens, concolorous with pileus or slightly paler; flesh pallid brownish grey, slowly darkening on prolonged exposure to air. Cuticle composed of parallel to interwoven, thin-walled, septate hyphae 3.5-6.5 µm diam., with dark brown contents in KOH; caulocystidia numerous, similar to pilocystidia. spores: spore print white; spores broadly elliptical to obovate, obliquely apiculate, apiculus to 1.5-(2) µm long, 7-9-(10.5) X 6-8 µm, ornamentation of amyloid verrucae to 0.5 µm high, in confluent groups, joined by fine amyloid ridges and forming a partial reticulum, or occasionally isolated; plage indistinct. hymenium: basidia hyaline, clavate, 36-60 X 7.5-10.5 µm, 4-spored, sterigmata to 7 µm long; pleurocystidia scattered, numerous, broadly fusiform or subclavate, apices acuminate, strangulate, or capitulate, hyaline, thin-walled, contents refractive in KOH, projecting to 25 µm beyond basidia, 60-110 X 6-12 µm, cheilocystidia similar to pleurocystidia but shorter. hymenophoral trama: heteromerous, intermixed. context of pileus: pallid, greyish white, firm, darkening on prolonged exposure to air; structure heteromerous, clamp connections absent: taste: lamellae and context mild. chemical characters: Formalin on context—faint pink to salmon pink; phenol on context—slowly deep vinaceous; FeSO4 on context—pallid salmon pink; guaiacol on stipe base—rapidly salmon pink, darkening to orange-red; KOH on pileus—darkening; on context —n.r.; NH4OH on pileus—darkening; on context—n.r.

Solitary or gregarious under Nothofagus.

Pileus centraliter depressus ad infundibulifomem 4.5-11 cm diam., griseo-fuscus, viscidus, glaber, subtiliter rugulosus; veil vestigia deficiunt; margines integri, crassi, non pectinati. Lamellae adnatae ad subdecurrentes ad 8 mm altae, pallide cremeo-ochraceae, interdum ad maturitatem decoloratae; lamellulae numerosae in tribus seriebus inaequalibus. Stipes 3-5 cm longus, basim angustatus, 1.2-2.5 cm diam., solidus, siccus, concolor cum pileo. Sporae late ellipticae ad ovatas 7-9-(10.5) x 6-8 µm, amyloides ornatae.

The firm context which slowly darkens on exposure to air and regularly arranged lamellulae indicate that this species belongs in section Compactae, subsection Compactae, as defined by Shaffer (1962). Russula griseobrunnea may be distinguished from the other New Zealand representative of subsection Compactae by the slowly darkening context, mild taste, and salmon pink reaction to FeSO4

holotype, pdd 30624