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 Add this item to the list  828505 Original description
   
Remarks (public):Notes ― Russula mediterraneensis belongs to the R. globispora complex of subsect. Maculatinae, and is therefore related with R. mattiroloana, but differs because of its larger basidiomata, its hymenophore comprised of a daedaleoid, loculate inner part and a clearly lamellate external part, its subglobose to ellipsoid spores with lower warts and a distinct amyloid suprahilar plage, its trama and context featuring abundant sphaerocytes, and its ecological association with broadleaved trees. The large spore size (up to 17 µm) is similar to that observed in R. globispora and R. mattiroloana, but different from those found in R. dryadicola and R. heilongjiangensis. 
Description type:Original description 
Description:Basidiomata russuloid, small to medium sized, pseudoangiocarpic, stipitate. Pileus 2.3–4.3(–5.2) cm wide, initially globose to subglobose, sometimes lobate, almost completely closed and covering the whole stipe except its base, later convex to plane, opened basally and exposing a lamellate hymenium, with an involute, dentate margin; rugulose, finely tomentose, white or whitish at first, sometimes with translucent spots, especially at the periphery and margin, later yellowish with ochraceous areas (4A2–A3) and finally mostly bicoloured, yellowish buff (4A4) to ochraceous buff (5A4), with brown maculae (6C8–7D8). Hymenophore irregularly loculate inside, daedaleoid, lamellate in the most external parts; locules large, 2–5 × 0.2–1 mm (0.5–1 per mm), labyrinthoid or flexuous in cross-section; lamellae irregular, more or less sinuous, frequently anastomosing and bifurcate, adnate, initially white, later cream, yellowish to ochraceous (4A3–A7), and finally ochre-orange or ochre-buff (6C8), with concolourous, acute or obtuse edges; white remnants of a partial veil can be observed in lamellae edges of some young basidiomata; fresh spore mass in locules yellowish white (4A2). Stipe-columella 1.6–4.2 × 0.7–1.8 cm, percurrent, well-developed, cylindrical, straight or rarely flexuous, central or eccentric, white, initially solid and later medullary, usually broadening but rarely also tapering at the base; context white, not changing after contact with air. Odour pleasantly fruity, of pear or reminiscent of yoghourt and fruit; taste mild to slightly acrid. Spores (8–)10–15(–17) × (7–)9–14(–15) μm, Q = (1.0–)1.10–1.25(–1.3), very variable in form and size, globose, subglobose, broadly ellipsoid to ovoid, heterotropic, echinate, some with one large, central oil drop; warts 0.6–1(–1.5) μm high, amyloid, irregularly conical or truncated, scattered or packed in few groups, with some verrucae among them; hilar appendix 1.2–1.8 µm long, cylindrical, with a distinct amyloid suprahilar plage in its base and conserving a non-functional apicular drop as in R. mattiroloana. Basidia (1–)2–3(–4)-spored, 30–55 × 11–18 μm, clavate, some of them with one or more oil droplets and amorphous yellowish content; sterigmata (4–)6.5–7.5 µm long. Basidioles 30–35 × 10–15 μm, clavate. Macrocystidia abundant (40–)70–130(–180) × 12–20 μm, subcylindrical, lanceolate to fusiform, thin-walled or slightly thick-walled in the central portion, 1–1.6 μm thick, with abundant amorphous yellowish content, and an obtuse to acute or subulate apex, sometimes rostrate. Paraphysoid cells scarce, 12–26 × 6–9 µm, cylindrical, entire or 1-septate. Subhymenium cellular, consisting of 3–4 strata of globose to prismatic cells 9–28 µm in diam. Hymenophoral trama heteromerous, made of hyaline, loosely interwoven septate hyphae 3–9 μm wide, with abundant sphaerocytes 21–47 µm in diam, and some gloeoplera 2–7 µm in diam. Pileipellis and context 100–300 µm thick; pileipellis composed of (1) a trichodermal suprapellis made of erect to semi-erect, septate hyphae 2–6 µ in diam, and abundant clavate, septate dermatocystidia 30–160 × 5–10 µm, and (2) a prosenchymatous subpellis of intricate hyphae 2–6 µm in diam. Pileal context heteromerous, composed of septate hyphae 2–6 µm in diam, mixed with several inflated hyphae and abundant nests and columns of sphaerocytes 21–47 μm in diam. Stipitipellis a texture of interwoven, branched hyphae similar in shape and content to pileipellis dermatocystidia. Habitat, Distribution & Season ― Gregarious, subepigeous among plant debris, in broadleaved woods of Quercus and Castanea, on siliceous soil. Summer. Occurring in the central and east-Mediterranean regions, in Greece and Italy, from sea level up to 1000 m of altitude. 
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