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 Add this item to the list  804644 Original description
Page number:175 
Remarks (public):Russula atroaeruginea is characterized by its dark-green intermixed with radially yellowish-tinged (striate) pileus, whitish to pale-cream spore print, and basidiospores with thin low fine ornamentations (<1.0 µm tall). The dark-green pileus contrasting with the whitish (often green-tinged) stipe is a good field character, although it is sometimes difficult to distinguish this species against from the green forest surroundings. This species should be placed in the Russula sect. Griseinae (Jul. Schäff.) Romagn. based on its mildflavored context, pileipellis lacking primordial hyphae and red pigments but with typical multiseptate (often subulate) hyphal extremities, and unicellular pileocystidia that blacken in SV.
Romagnesi (1967) recognized 5 greenish tinged species in sect. Griseinae: R. pseudoaeruginea (Romagn.) Kuyper & Vuure, R. aeruginea Fr., R. medullata Romagn., R. stenotricha Romagn., and R. anatina Romagn. The morphologically similar R. aeruginea, R. anatina, R. cyanoxantha f. peltereaui Singer, R. medullata, and R. pseudoaeruginea have been reported in eastern Asia (Tai 1979, Ying et al. 1982, Imazeki & Hongo 1989, Ying 1989, Shimono et al. 2004). Russula pseudoaeruginea, however, has a gray-tinged green olive or somewhat cream and pale-brown intermixed pileus and an ochreous-cream spore print (Romagnesi 1967, Sarnari 1998); it often grows in temperate to boreal deciduous forests dominated by Tilia and Quercus spp. (Romagnesi 1967, Hansen & Knudsen 1992), while R. atroaeruginea grows in conifer forests dominated by Picea spp.
in alpine subtropical regions.
Another taxon superficially resembling R. atroaeruginea is R. aeruginea, a very common species originally described from Europe which grows in subalpine coniferous to mixed forests containing Betula, Pinus, and Picea. However, R. aeruginea has a green-tinged pileus with a darker pileus centre, whitish stipe with rusty spots, a slightly acrid taste, cream-colored spore deposits, and spores with many fine lines formed by connected low warts (Schaeffer 1952, Romagnesi 1967, Roger 1981, Woo 1989, Hansen & Knudsen 1992, Sarnari 1998). Russula aeruginea can be distinguished from R. atroaeruginea by its more or less discolored pileus, which is often spotted with scattered, rusty spots. Russula atroaeruginea is also easily distinguished from three other species originally described from France: R. medullata grows under deciduous trees of Corylus, Populus, Fraxinus, Betula, Fagus, Castanea, and Quercus, has an ochre (III a, b-c) spore print, spores with isolated warts, and rare pileocystidia (Romagnesi 1967, Hansen & Knudsen 1992); R. stenotricha has a grayish-green pileus, slightly spicy lamellae, short obtuse pileipellis terminal cells, and short wide pileocystidia 25-50 x 5-9 (12) µm (Romagnesi 1967, Hansen & Knudsen 1992); and R. anatina has long cystidia 60-130 x 6.7-12 µm (Romagnesi 1967).
Also similar to R. atroaeruginea is the green form of R. cyanoxantha (Schaeff.) Fr. (= R. cyanoxantha f. peltereaui), which differs in its elastic lamellae, white (Ia) spore mass, basidiospores with scattered low warts that are never connected with fine lines, and slender cystidia 65-100 x 5.7-7 µm (Romagnesi 1967, Roger 1981, Hansen & Knudsen 1992).
Among the Russula species originally described from China, the morphologically related R. viridirubrolimbata J.Z. Ying differs from R. atroaeruginea by its finely rimose pileus, unchanging white context, isolated spore ornamentations, hyaline pleurocystidia, and a pileipellis without pileocystidia (Ying 1983).
Description type:Original description 
Description:Russula atroaeruginea G.J. Li, Q. Zhao & H.A. Wen, sp. nov. Figs 1-2
MycoBank MB804644
Differs from Russula aeruginea by its non-fading green pileus lacking scattered rusty spots and whitish to pale cream spore print.
Type: China. Sichuan Province, Daofu County, 25.VII.2007, Z.W. Ge 1540 (Holotype, HKAS53626, GenBank JX391970)
Basidiomata small to medium sized. Pileus 3-7 cm in diam., first hemispherical, then convex to applanate, sometimes slightly depressed above the stipe, blackish-green tinged, intermixed with radial greenish yellow fringe, Dull Blackish Green (XLI29ʹʹʹm) at centre, Sepia (XXIX17ʹʹm) when dry, never viscous; margin incurved first, straight when mature, sometimes undulate, not striate, Meadow Green (VI35k) to Antique Green (VI33m) with yellowish tinge of Oil Yellow (V25i) towards the margin, Verona Brown (XXIX13ʹʹk) when dry. Lamellae 10-15/cm at the edge, ≤7 mm wide, adnate to almost free, forked around the stipe, occasionally near the pileus margin, not interveined, cream to yellowish, Cream Color (XVI19ʹf), brittle; edge even, slightly narrowing towards the pileus margin; lamellulae occasional. Stipe 4-6 x 1-2 cm, central to slightly eccentric, smooth, not pruinose, cylindrical, ventricose toward the base, without annulus, whitish, often with pale-greenish tinge, part turning pale yellow when aged, sometimes with rusty spots, first unchanging, stuffed, hollow when mature. Context 3-5 mm thick from the lamellae attachment to the stipe, compact under pileus, white to whitish, no color change when bruised, turning slightly pale yellowish in age; taste mild; no distinct odor. Spore print whitish to pale cream (Romagnesi Ib-IIa).
Basidiospores [80/4/3] (6.3-) 6.8-8.1 (-9.0) x (5.9-) 6.1-7.4 (-7.8) µm, Q = (1.01-)1.04-1.23(-1.32) (Q =1.15 ± 0.07), subglobose to broadly ellipsoid or (sometimes) ellipsoid, verrucose; ornamentation amyloid, composed of warts mostly fused into fine lines, cristulate to subreticulate, with some isolated verrucae, <1.0 µm high; plage not or indistinctly amyloid. Basidia 40-48 x 9-11 µm, clavate, inflated towards upper half, 4-(rarely 2-) spored, projecting 7-13 µm beyond hymenium, hyaline in KOH; sterigmata 3-5 µm, pointed, straight to slightly tortuous. Pleurocystidia numerous, 72-115 x 9-13 µm, originating in subhymenium, projecting 35-50 µm beyond hymenium, thin-walled, clavate to subfusiform, sometimes with refractive contents; apices subacute to acute, at times with a moniliform appendage. Cheilocystidia not observed; lamellaredge sterile. Subhymenium 15-20 µm thick, composed of slender cylindrical cells 4-7 µm wide under basidia and inflated cells (15-)20-35(-45) µm in diam. next to trama. Pileipellis a trichoderm 200-300 µm thick, composed of 4-6 µm thick, slender hyaline hyphae without intracellular pigmentation; pileocystidia numerous, 40-70 µm long, sometimes inflating up to 7-10 µm wide, fusiform, with crystal contents but no septa, sharply blackened in SV. Stipitipellis not well developed, a cutis composed of thin-walled, septate, cylindrical hyphae 3-6 µm wide; caulocystidia absent. Clamp connections absent in all tissues.
Ecology & distribution: Single or gregarious in conifer forest (Picea spp.) in July and August in China (Sichuan, Xizang, and Yunnan).
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