Russula rajendrae A. Ghosh & K. Das, 2017

Ghosh, Aniket & Das, Kanad, 2017, Russula (Russulaceae) in western Himalaya 1: Two new species from subg. Russula, Phytotaxa 323 (3), pp. 237-252 : 240-245

Russula rajendrae A. Ghosh & K. Das sp. nov. Figs. 3 & 4

MycoBank:—MB 821641

Diagnosis:—Differs from other known species of Russula subsect. Russula by the combination of features: pale red to venetian pink or pastel red colored pileus with grayish yellow patches in the center, white spore print, variable shapes of the apices of the cystidia (capitate, rounded, moniliform, appendiculate or pointed apex) and ITS sequence data.

Type:— INDIA. Uttarakhand: Rudraprayag-district, Baniyakund , N30°29.213’ E79°10.246’, Alt. 2555 m a.s.l., on the soil under Quercus sp. in temperate forest, 24 July 2016, A. Ghosh, AG 16-1188 (Holotype CAL!; Isotype GUH!) .

Etymology:—In recognition of Prof. Rajendra P. Bhatt for his contribution to the wild mushrooms of Uttarakhand and Himachal Pradesh in India.

Description:— Basidiomata 60–65 mm in height, small to medium-sized. Pileus 42–46 mm diam., convex to planoconvex, then applanate with slightly depressed center, margin decurved to plane with maturity, entire, tuberculatestriate, surface finely wrinkled, viscid when moist, then dry, glossy, pale red to venetian pink (10A3) or pastel red (10A4–10A5) with central grayish yellow (2A4–2A6) patches, pale orange (5A3) to light orange (5A4–5A5) with KOH, cuticle peels up to centre; pileus context chalky white (1A1–2A1), up to 2 mm thick, unchanging when exposed. Lamellae adnexed to subdecurrent, close to rather crowded (9–10 per cm), chalky white (1A1–2A1), up to 3 mm in width, narrowing towards the margin, forked near the stipe apex, entire, concolorous edges, unchanging when bruised. Lamellulae present in four tiers. Stipe 40–42 × 19–22 mm, cylindrical to subclavate, centrally attached, dry, smooth, brittle, chalky white (1A1–2A1) turning reddish brown (8D6–8D7) and salmon pink with guaiacol and FeSO 4 respectively. Stipe context hollow, chalky white (1A1–2A1) unchanging after exposure but reddish brown (8D6–8D7) with guaiacol, salmon pink with FeSO 4. Taste acrid. Spore print white (1A1).

Basidiospores (–7)7.62–8.28–8.94(–10) × (–6)6.85–7.43–8.01(–8.5) μm, (n = 60, Q = (–1)1.07–1.12–1.17(–1.23), subglobose to broadly ellipsoid, rarely globose; ornamentation amyloid, composed of warts up to 1 μm high and ridges that are aligned or connected to form an incomplete to complete reticulum, with few isolated warts; suprahilar plage inamyloid, apiculus up to 2 μm high. Basidia 39–54 × 11–16 μm, 4-spored, cylindric, subclavate to clavate, sterigmata up to 8 μm long. Pleurocystidia 40–85 × 7–11 μm, abundant, cylindric to subclavate with capitate, rounded, moniliform, appendiculate, or pointed apices, emergent up to 34 μm beyond basidiole tips; content dense, turning brown-grey with sulphovanillin. Cheilocystidia 32–53 × 7–10 μm, cylindric to subclavate with capitate or rounded apex; content dense, turning brown-grey with sulphovanillin. Lamellae edge fertile with basidia and cystidia. Subhymenium 12–15 μm thick, pseudoparenchymatous. Pileipellis up to 100 μm thick, an ixotrichoderm, composed of branched, septate, short terminal hyphae (3–5 μm diam.) with rounded or blunt apex; primordial hyphae not observed. Pileocystidia 5–10 μm diam., 0–3 septate, numerous, short to very long, cylindrical, subclavate to clavate with rounded apex, content dense, brown-grey with sulphovanillin. Clamp connections and laticiferous hyphae absent from all tissues.

Habitat and distribution:—Scattered under Quercus sp. in temperate forest of Western Himalaya.

Specimens examined:— INDIA. Uttararakhand , Rudraprayag-district, Baniyakund, N30°29.213’ E79°10.246’, Alt. 2555 m a.s.l., on the soil under Quercus sp. in temperate forest, 24 July 2016, A. Ghosh, AG 16-1188 (Holotype CAL!; Isotype GUH!) .

Notes:—The combination of macro- and micromorphological features including the epicutis with or without encrusted dermatocystidia, the absence of primordial hyphae, the acrid or very acrid taste, the well-differentiated dermatocystidia in the epicutis, and the white spore print) undoubtedly place Russula rajendrae in subg. Russula sec. Russula subsect. Russula ( Sarnari 1998) . In the field R. rajendrae is distinct from other species of this group by its pale red to venetian pink or pastel red colored pileus with grayish yellow patches in the center and micromorphologically it is separated from allied species by the combination of variable shapes of the cystidial apex (capitate, rounded, moniliform, appendiculate or pointed apex).

The newly undescribed species R. rajendrae clustered with an unknown Russula sp. HMAS 276793 [GenBank accession no. LT602951; query coverage 98%; Identity 95% and 0.0 E value] collected from China. Unfortunately there are no micro- and macromorphological details available for this collection in any published literature.

R. rajendrae is similar to R. emetica (Schaeff.) Pers. , R. fragilis Fr. , R. betularum Hora , R. atrorubens Quél. , R. grisescens (Bon & Gaugué) Marti , R. laccata Huijsman , R. nana Killerm. , R. silvestris (Singer) Reumaux , and R. chiui G.J. Li and H.A. Wen. on account of the combination of the brightly red-tinged pileus, the white stipe, the acrid context, the pileipellis without primordial hyphae and the septate pileocystidia. Russula emetica (the BLAST search) described from Europe, differs in having a bright red pileus that discolors gradually from the margin, a completely separable pileus cuticle, wider pileocystidia, 4.5–14 μm, and a preferred habitat with coniferous trees in peat bogs ( Murrill 1914; Romagnesi 1967; Singer 1986). R. fragilis , originally described from Europe, differs from R. rajendrae in having dark pink violet to gray pink pileus with a purple-black centre, sometimes with olive tones, notched or narrowly attached lamellae with finely crenate edges and a white stipe that becomes faintly yellow when old or bruised ( Sarnari 1998; Kränzlin 2005). Another species, Russula betularum (also appeared close in the BLAST search with an E value of 0.0) originally described from Europe, has a strongly discolored and or sometimes entirely white pileus, a preferred habitat in moist Betula forests with Sphagnum sp. and larger basidiospores 8–11.8 × 7.4–9.6 μm ( Romagnesi 1967; Bills 1984; Rayner 1985; Sarnari 1998). Similarly, R. atrorubens (appeared in close in the BLAST search and with an E value of 0.0), an European species, is distinct by its amyl acetate-smelling context, white stipe that is sometimes flushed with red near the base, yellow spore print, smaller (6.4–8 × 5.2–6.3 μm), oblong basidiospores with low ornamentation [0.5(0.6) μm high] and occurrence in damp coniferous woods of the subalpine zone ( Sarnari 1998; Kränzlin 2005; Li et al. 2015). Russula griseascens , originally described from Europe, is distinct by possessing a grayish context when wet, low spore-ornamentation (0.6–0.7 μm) and habitat under deciduous and coniferous trees with Sphagnum , ( Sarnari 1998; Li et al. 2015), whereas R. laccata (also appeared in BLAST search) an European species, has smaller basidiospores (6.5–9 × 6–7.5 μm) with low ornamentation (up to 0.5 μm high) and a distinct habitat being found in association with Salix herbacea and S. repens ( Rayner 1985; Sarnari 1998). Russula nana (appeared in BLAST search also & E value 0.0), an European species, has distant lamellae, smaller basidiospores (7.1–8.7 × 6.1–7.2 μm), low spore ornamentation (up to 0.5 μm high) and grows in alpine grassland in association with Salix herbacea , Alchemilla pentaphyllea , Betula spp . and coniferous trees ( Knudsen & Borgen 1982; Sarnari 1998, Kränzlin 2005). Another taxon, R. silvestris , originally described from Europe, is distinct by its slightly inrolled pileus margin, whitish lamellae, short terminal cells of the pileocystidia, and habitat in sandy soils ( Singer 1957; Galli 1996; Romagnesi 1967; Kibby 2012), whereas, R. chiui , an Asian species, differs in having small basidiomata (30–48 mm diam.), an absence of lamellulae, a white spore print, subglobose to broadly ellipsoid basidiospores with an ornamentation composed of amyloid warts and ridges forming a nearly complete to complete network and rarely intermixed with isolated verrucae, up to 1–1.3 μm high ( Li et al. 2015).

Considering the cap coloration, the present species may also be confused in the field with R. gracillima Jul. Schäff. , R. cremeirubra Murrill , R. nobilis Velen. However , R. gracillima , originally described from Europe, is separated from the present taxon by possessing moderately spaced lamellae, a slightly acrid taste, a presence of abundant, broad (5–10 μm) dermatocystidia and basidiospores ornamented with isolated and blunt warts ( Rayner 1985; Sarnari 1998; Galli 1996; Chou & Wang 2005; Kibby 2012), whereas R. cremeirubra (originally reported from Florida), differs from R. rajendrae by its rather distant, straw coloured lamellae, basidiospores with amyloid warts connected by fine lines which combine to form few meshes and a broken reticulum, pilear hyphae (2–6 μm diam.) with acute to rounded apex ( Murrill 1945; Hesler 1960; Fatto 1988; Kibby & Fatto 1990). Russula nobilis (= R. mairei Singer ), described originally from Europe, differs in having a white stipe, white gills with a greenish tinge, basidiospores with low ornamentation (0.5–0.6 μm) and a fruity, honey-like, pleasantly spicy or gingerbread smell ( Romagnesi 1967; Sarnari 1998; Li et al. 2015).

Figures

FIGURE 3. Russula rajendrae sp. nov. (AG 16–1188, Holotype). a–d. Fresh and dissected basidiomata in the field and at base camp; e–h. Transverse section through lamellae showing pleurocystidia; i. Radial section through pileipellis showing elements; j. Transverse section through lamellae showing cheilocystidia; k. Image of basidiospores under SEM. Scale bars: b = 65 mm; c–j = 10 μm; k = 2 μm. Photographs by A. Ghosh.

FIGURE 4. Russula rajendrae sp. nov. (AG 16–1188, Holotype) a. Dissected basidioma; b. Radial section through pileipellis; c. Basidiospores; d. Basidia; e. Pleurocystidia; f. Cheilocystidia. Scale bars: a = 10 mm; b–f = 10 μm (drawings by A. Ghosh).