Russula haematina G.J. Li & Chun Y. Deng, sp. nov.

Index Fungorum number: IF 570741; Fungal Names Number: FN 570741; Facesoffungi number: FoF 14527; Fig. 1

Etymology – Referring to the brightly red pileus.

Holotype – HGAS-MF 013965.

Basidiomes medium sized. Pileus 35–48 mm in diam, first plano-hemisphere, then convex, flat when mature, a tinge of brightly red (B82928, C52242), often intermixed with pinkish red tinge (F87B90, F58FA3), sometimes faded to a pinkish yellow tinge (FCC1A2, FED1B0) at center, smooth, dull, slightly viscid when wet; margin not striate, rarely cracked, peeling about 1/3 from the edge. Lamellae adnate, 2–4 mm in height, 12–16 pieces per centimeter at edge, not forked, interveined, white (FFFFFF), unchanging when bruised, lamellulae not observed. Stipes 31–43×10–14 mm, central to subcentral, cylindrical, rugulose longitudinally, pale pinkish red (E08087, F496A1), partly white (FFFFFF), turning pale ocher (B49B57, 9A7C37) when injured and old, smooth, dull, not viscid when wet, gradually attenuate downward the base, first stuffed, hollow when old, annulus absent. Context 3–4 mm thick at pileus center, white (FFFFFF), turning pale ocherous yellow (BC8B1F, DBB960) when bruised and old, taste mild, smell indistinct. Spore print pale cream (Romagnesi IIa–IIb).

Basidiospores [150/3/3] (6.3–) 6.6–8.4 (–8.8) × (5.3–) 5.7–7.7 (–8.2) μm, Q =1.01–1.27, Q =1.13±0.06), hyaline, subglobose to broad ellipsoid, rarely globose, ornamentations amyloid, up to 0.7 μm in height, composed of long ridges interconnected as complete reticulum, isolated warts and short crests absent, suprahilar area plage distinct and amyloid. Basidia 31–42×10–12 μm, subcylindrical to subclavate, rarely clavate, four-spored, projecting 10–20 μm beyond hymenium, hyaline, sterigmata 5–7 μm long. Hymenial cystidia rare, 65–90×12–14 μm, fusiform, unchanging or slightly greyish in SV, apex constricted, mostly forming an elongate appendage. Pileipellis two layered, not clearly delimited from the spherocytes in context; epipellis a trichoderm, ca. 30–70 μm thick, hyphae erect to oblique, often branched, hyaline; terminal cells cylindrical to flexuous, 5–10 μm wide, often with a capitate or mucronate apex, rarely containing granulate contents slightly greyish in SV, subapical cells sometimes protruding, irregular, 7–14 μm wide; primordial abundant, hyphae 3–6 μm wide, cylindrical, surface with acido-resistant incrustations; subpellis composed of somewhat gelatinized, loosely interweaved, rarely branched and septate, hyaline hyphae 3–7 μm wide, rarely intermixed with spherocytes 10–25 μm in diam.

Habitat – Single or scattered in coniferous and broadleaved intermixed forest.

Material examined – China, Guizhou Province, Guiyang, Yunyan District, Qianlingshan Park, in coniferous and broad-leaved forest, 1 September 2019, Chun-Ying Deng 2018–48 (HGAS-MF 013965, holotype).

GenBank number – ITS=MT505891.

Notes – Phylogentically, in Russula sect. Roseinae (Fig. 2), the new species Russula haematina forms a clade with speciemens of Rosa clade. The other members of the clade can be distinguished from R. haematina as follows: R. amarissima has violaceous purple to cigar brown pileus, bitter taste of context, narrower basidia 8–10 μm wide, and longer hymenial cystidia up to 115 μm long; R. rosea has longer hymenial cystidia with obtuse apex and narrower epipellis hyphae 3.2–4.5 μm wide (Romagnesi 1985; Sarnari 2005). There are two species, R. guangxiensis and R. hakkae of R. sect. Roseinae which were described from South China. These two species also have brightly red pileus. Russula guangxiensis can be differentiated from R. haematina by its white stipe, mild tasted context, smaller basidiospores (5.9–6.9×4.9–6.1 μm), and shorter and narrower hymenial cystidia (55–63×7–12 μm); R. hakkae differs in the ornamentations of basidiospores composed of dense and isolated warts (0.9–1.2 μm in height), longer and wider basidia, and round to subacute, often shortly appendiculate to subcapitate apex of hymenial cystidia (40–50×10–15 μm, Ariyawansa et al. 2015).

Figure 1 – Microscopic structures of Russula haematina (HGAS-MF 013965, holotype). a Basidiomes. b Basidiospores. c Basidia. d Hymenial cystidia. e Suprapellis of pileipellis. Scale bars: a=10 mm, b–e=10 μm

Figure 2 – Maximum Parsimony strict consensus tree illustrating the phylogeny of Russula haematina (holotype) with related species in R. sect. Roseinae based on ITS sequences. Branches are labeled with maximum likelihood bootstrap higher than 50%, and Bayesian posterior probabilities more than 0.9 respectively. Sequences of R. sect. Lilaceinae were used as outgroup to root trees. The new isolates are in bold