Russula hakkae G.J. Li, H. A. Wen & R.L. Zhao, sp. nov.
Index Fungorum number: IF551493; Facesoffungi number: FoF01048; Fig. 1.
Etymology: refers to the hakka people living in the type locality.
Holotype: CHINA. Guangdong Province, Meizhou City, Meixian County, Longwen Township, 9 August 2013, Xin – Hua Chen 34 (HMAS 267765).
Basidiomata small to large sized. Pileus 40 – 100mmdiam., first hemispheric, then flat hemispheric to applanate, planoconvex to convex when mature, smooth, viscid when wet, slightly glabrous when young, peeling 1/4 – 1/2 from the edge, sometimes desquamated in small patches; brightly tinged with SpectrumRed (I1), Peach Red (I5b) to Scarlet (I5), intermixed with pink tinge of Rose Doree (I3b) to Strawberry Pink (I5d) in center, Eosine Pink (I1d), Hermosa Pink (I1f) to Hydrangea Pink (XXVII5″f) towards margin. Lamellae adnate, equal, 2 – 6 mm high, 17 – 22 pieces per cm at the edge, rarely forked near the stipe and pileal edge, often interveined, white when fresh, lamellulae absent. Stipe central to subcentral, 5 – 7 × 0.8 – 2 cm, subcylindrical, slightly tapering towards the apex and base, smooth, sometimes rugulose longitudinally, mostly pinkish tinged with Eosine Pink (I1d) to La France Pink (I3f), partly longitudinally fade to White (LIII), a tinge of Pale Yellow–Orange (III15f) when injured, old and dry, first unchanging, spongy to hollow when mature. Context 2 – 5 mm thick from the lamellae attachment to the stipe, White, unchanging or becoming Sanford’s Brown (II11k) when injured, fragile, odour indistinct, taste acrid. Spore print White (Romagnesi Ia).
Basidiospores [200/10/10] (6–) 6.7 – 8.1 (−8.8) × (5.5–) 5.8 – 6.9 (−7.5) μm, Q = (1.06–) 1.13 – 1.27 (−1.31), (Q = 1.17 ± 0.06), hyaline, subglobose to broadly ellipsoid, rarely ellipsoid; ornamentation composed of dense, amyloid warts that are 0.9–1.2 μm high; suprahilar are distinct and amyloid. Basidia 40 – 50 × 10 – 15 μm, mostly with four sterigmata 3 – 7 μm long, hyaline, sometimes yellowish in KOH, subclavate to clavate, rarely cylindrical. Pleuroystidia scattered, 55 – 77 × 8 – 12 μm, distinctly projecting 15 – 25 μm beyond the basidia, subfusoid to subcylindrical, sometimes clavate to subclavate, apices round to subacute, often appendiculate to subcapitate, thin–walled, contents granular to crystal, weakly grey in SV. Cheilocystidia same as pleurocystidia. Subhymenium a cellular layer 20 – 30 μmthick composed of inflated cells 10 – 25 μm diam., hyaline, sometimes pale yellowish in KOH. Pileipellis orthochromatic in cresyl blue, composed of epipellis and subpellis; epipellis a palisade 25 – 50 μm thick, composed of thin-walled, dense, ascending to erect, cylindrical hyaline hyphae 3 – 8 μm wide arising from a gelatinous matrix; terminal cells 6 – 10 μm wide, septate, clavate to cylindrical, apex obtuse; subapical cells often irregular, inflated, branched, up to 30 μm diam., subpellis composed of inflated cells same as the subapical cells, forming a pseudoparenchymatic region, interweaved hyaline hyphae 2 – 6 μm wide; primordial hyphae septate, protruding, with heteromorphous-opalescent inclusions and acid-resistant incrustations, 3 – 7 μm wide, apex obtuse; pileocystidia not observed. Stipitipellis a cutis, composed of filamentous hyphae 3 – 6 μm diam., interweaved with inflated cells 10–25 μmdiam., hyaline, some hyphae yellowish to pale ochre in KOH; caulocystidia absent. Trama composed of sphaerocytes 35–100 μm diam. Clamp connections and lacticiferous hyphae absent from all tissues.
Habitat and distribution: Solitary to scattered in broad leaved forest dominated by Lithocarpus spp.
Additional specimens examined: CHINA, Guangdong Province, Meizhou City, Meixian County, Longwen Township, 9 August 2013, Xin-Hua Chen 9 (HMAS 267862); ibid., Xin-Hua Chen 4 (HMAS 267870); ibid., Xin-Hua Chen 45 (HMAS 267767); ibid., Xin-Hua Chen 9 (HMAS 267862); ibid., Xin-Hua Chen 2 (HMAS 267865); ibid., Xin-Hua Chen 34 (HMAS 267765); ibid., Xin-Hua Chen 37 (HMAS 267768); ibid., Xin-Hua Chen 6 (HMAS 267861); ibid., Xin-Hua Chen 15 (HMAS267864); ibid., Xin-Hua Chen 25 (HMAS 267769).
Notes: Russula hakkae can be easily distinguished from most of the other taxa of subsection Roseinae by its stabile pinkish tinge of stipe, acrid context taste, and very dense basidiospore ornamentation up to 1.2 μm. There are only a few members of subsection Roseinae which have pinkish tinged stipe. These taxa can be distinguished from R. guangxiensis as follows. Russula peckii Singer [as “undescribed species” in subsection Roseinae in Adamčík and Buyck (2012)] has a crenulate lamellar edge, a mild context taste, an ixotrichoderm pileus epicutis, and a habitat of coniferous forest (Peck 1907; Singer 1935). Russula pseudopeckii Fatto has a pileus edge with a few long lamellulae, a fruity to nondescript context odour, a cream spore print, and a basidiospore ornamentation composed of low warts (0.4–0.6 μm). Russula rubellipes Fatto has a mild context taste, a cream spore print, and some warts of basidiospore ornamentations forming a variable number of connectives (Fatto 1998).
Fig. 1 Russula hakkae (holotype) a Basidiocarps b Basidiospores c Basidia d Pleurocystidia e Pileipellis.