Russula coronaspora, Song & Xie & Buyck, 2021

Song, Yu, Xie, Xiu-Chao & Buyck, Bart, 2021, Two novel species of subgenus Russula crown clade (Russulales, Basidiomycota) from China, European Journal of Taxonomy 775, pp. 15-33 : 17-25

Russula coronaspora Y.Song sp. nov.

MycoBank: MB837425

Index Fungorum: IF558819

Figs 3–4 , 7A

Diagnosis

Russula coronaspora sp. nov. is mainly characterized by its small basidiocarps with pinkish brown pileus, interveined lamellae with few lamellulae, small spores ornamented with sparse, cylindrical and isolated spines, hymenial and dermatocystidia weakly SV+ or SV-, pileipellis gelatinized and orthochromatic in cresyl blue, pileocystidia mostly septate and sometimes branched.

Etymology

Named after its basidiospores which resemble a coronavirus.

Type material

Holotype CHINA • Guangdong Province, Zhaoqing City, Dinghushan Biosphere Reserve , on the ground in evergreen broad-leaf forest; 22 Apr. 2019; Y. Song, K19042201; GenBank nos: MN275689 (ITS), MN839580 (nLSU), MN839630 (mtSSU), MT085562 (rpb1), MT085657 (rpb2), MT085600 (tef1); GDGM79711 .

Additional material examined

CHINA • Guangdong Province, Zhaoqing City, Dinghushan Biosphere Reserve , on the ground in evergreen broad-leaf forest; 6 Apr. 2016; Y. Song, K16040650; GenBank no: MN275690 (ITS); GDGM79712 .

Description

Basidiocarp small sized. Pileus 2.5–4 cm in diam., hemispherical to convex at first, turning applanate with depressed center at maturity; surface glabrous, dry, viscid when wet, pinkish (#FDF2E9) or brownish (#FCF3CF), sometime white (#FFFFF0) at margin; margin entire, sometimes cracked, striate when young. Lamellae white (#FFFFF0), interveined, mixed with few, dispersed shorter lamellulae; edge entire, concolorous, smooth. Stipe central, 2–3.5 × 0.5–1 cm, cylindrical, sometimes tapering upwards, solid at first, turning spongy to hollow with age, fleshy, fragile, white (#FBFCFC). Context white, not changing when bruised; taste mild; odor indistinct. Spore print pale cream (#FBFBEF).

Basidiospores subglobose to ellipsoid, rarely globose, very small, (60/3/2) (4.5–)4.7–5.1–5.6 (–6.2)× (3.6–) 3.8–4.2–4.6(–4.8) μm, [Q = 1.12–1.20–1.32(–1.38)], hyaline in 5% KOH; ornamentation amyloid, spines cylindrical to subclavate, sometimes tapering upwards or downwards, less than 2 μm in height, sparsely distributed [2–(4–) 5 in a 3 μm diam. circle], isolated, long warts scattered, never connected; suprahilar spot indistinct, amyloid. Basidia clavate, 2- or 4-spored, thin-walled, often with irregular contents or droplets, (19.5–)21.5–25–30(–35) × 7–9–10.5(–11) μm; sterigmata 2.4–5.1×1.2– 1.5 μm. Hymenial gloeocystidia on gill sides subcylindrical to fusiform, with papillate, mucronate or branched apices, thin-walled, with irregular refractive contents, weakly SV+ or SV-, (21–)23.5–33– 49(–51) × 4.5–5.5–7.5 μm; on gill edges not abundant, 33–40–46(–50) ×4.5–5–6 μm. Subhymenium pseudoparenchymatous.

Lamellar trama composed of numerous sphaerocytes surrounded by connective hyphae, sphaerocytes up to 21 × 19 μm. Pileipellis orthochromatic in cresyl blue, gelatinized, composed of ascending to erect hyphae, 33–80 μm thick; terminal cells cylindrical, with obtuse or tapering apices, thin-walled, hyaline, (7.5–)8.5–14–19(–24) ×1.5–2–3 μm. Pileocystidia abundant, cylindrical to fusiform, with obtuse or tapering apices, mostly 1- or 2-septa, sometimes branched, with refractive contents, weakly SV+ or SV-, (29–)30.5–62–94.5(–98.5) ×3–4.5–6(8.5) μm. Stipitipellis a cutis, composed of septate and hyaline hyphae measuring 1–3 μm wide; terminal cells cylindrical with obtuse apices, thin-walled, hyaline. Caulocystidia frequent, cylindrical, obtuse or papillate, mostly septate, with refractive contents, (30.5–)33–39.5–49(–57.5)×2–3–4 μm. Clamp connections absent in all tissues.

Figures

Fig. 3. Russula coronaspora Y.Song sp. nov. (GDGM79711, holotype). A–C. Fruiting bodies. D–E. Pileipellis. F–G. Basidiospores under scanning electron microscope. Scale bars: A–C = 1 cm; D = 25 μm; E = 10 μm; F–G = 2 μm.

Fig. 4. Russula coronaspora Y.Song sp. nov. (GDGM79711, holotype). A. Basidia. B. Pleurocystidia. C. Cheilocystidia. D. Terminal elements in pileipellis. E. Pileocystidia. Scale bars = 10 μm. Drawing by Yu Song.

Fig. 7. Line drawings of basidiospores. A. Russula coronaspora Y.Song sp. nov. (GDGM79711) B. R. minor Y.Song sp. nov., holotype (GDGM79686). Scale bars = 1 μm. Drawing by Yu Song.