Russula pseudosinoparva, Zhou & Shen & Hou, 2023

Zhou, Hao, Shen, Xiao-Ye & Hou, Cheng-Lin, 2023, A new species of Russula subgenus Russula (Russulaceae, Russulales) from Yanshan Mountains, North China, Phytotaxa 609 (3), pp. 195-208 : 202-204

Russula pseudosinoparva sp. nov. H. Zhou & C. L. Hou ( Figs. 3 , 4 , 5 )

MycoBank: MB 847567

Diagnosis:— Russula pseudosinoparva is characterised macroscopically by small basidiomata with a dark red to dark pink pileus; lamellae usually forked near the stipe, with a small number of lamellulae; and microscopically by a suprapellis made up of loose and upright hyphae. Morphologically, R. pseudosinoparva is easily confused with Russula puellaris Fr. (1983: 362) . Russula pseudosinoparva differs from R. puellaris by having usually forked lamellae and bigger basidia.

Etymology:—The epithet “ pseudosinoparva ” refers to its related phylogenetic position to Russula sinoparva .

Holotype:— CHINA. Hebei Province, Xinglong County, Wulingshan Mountains National Nature Reserve , 40.272411 N, 117.13521 E, elev. 222 m, 19 August 2019, coll. C. L. Hou, J. Q. Li and G. Q. Cheng ( BJTC L131 ).

Description:— Basidiomata small size. Pileus 10–25 mm diam., initially hemispherical when young, flattened when mature, slightly concave at the center, dry at the edge, slightly viscid in the center, smooth when young, striate when old, cracking near the margin with age, smooth, peeling to 1/3 of the radius, pure red (#e60039) to dark red (#9a0026), central dark pink (#810041) to very dark pink. (#680034). Lamellae white (#ffffff) when young, white (#ffffff) to very pale cream (#ffffd4) when mature, with 9–11 gills per cm of cap circumference, brittle, unequal, usually forked near the margin. Stipe 31–55 × 5–12 mm, white (#ffffff), subcylindrical, smooth, dry, non-brittle, gradually broadening towards base. Pileus context 2–6 mm thick, white (#ffffff) without color change when bruised. Spore print not observed. Taste and smell not observed.

Basidiospores (5.8–)6.8–7.2–7.9(–8.8) × (5.5–)5.9–6.3–6.9(–7.2) μm, [Q = (1.02–)1.06–1.11–1.25(–1.35)], subglobose to broadly ellipsoid, ornamentation consisting of small, moderately distant [(4–)5–7(–8) in a 3 μm diameter circle] amyloid warts, 0.4–1.2 μm high, occasionally to frequently fused in pairs or triplets, short branched chains [(0–)1–3 (–4) in the circle], frequently connected by short or long, fine line connections [(0–) 1–2 in the circle], suprahilar spot large, inamyloid. Basidia (33–)36–39–45(–52) × (11–)13–14–15 (–17) μm, 2–4-spored, clavate, with particles and oil droplets, basidioles clavate or subcylindrical, ca. 7–16 μm wide. Hymenial cystidia on lamellae faces (39–)48–51–63(–70) × (8.1–)8.9–10–12(–14) μm, clavate or fusiform, apically often obtuse or mucronate, sometimes with 2–6-μm-long appendage, contents with refracted inclusions, or some-times with granulose or crystalline, turning ash black (#0d0d0d) in SV. Hymenial cystidia on lamellae edges smaller and narrower to hymenial cystidia on lamellae sides, (23–)27–33–39(–46) × (4.4–)5.4–6.8–10(–12) μm, clavate or subcylindrical, apically often obtuse, sometimes with 2–4 μm long appendage, contents granulose. Pileipellis orthochromatic in Cresyl Blue, sharply delimited from the underlying context, 90–150 μm deep, two-layered. Suprapellis 40–70 μm deep, with strongly gelatinized loose and upright hyphae. Subpellis 50–90 μm deep, composed of horizontally oriented, relatively dense, intricate, 3–8 μm diam hyphae. Hyphal terminations near the pileus margin occasionally branched, sometimes flexuous, thin-walled; terminal cells (10.4–)11–13–19(–22) × (2.8–)3.2–3.8–5.6(–7.1) μm, subcylindrical or clavate, apically mainly obtuse, occasionally attenuated, subterminal cells often wider, ca. 3–6 μm diam, always unbranched. Hyphal terminations near the pileus center similar to those near the pileus margin; terminal cells (14–)15–24(–28) × (2.9–)3.5–6.1(–7.2) μm, subcylindrical or clavate, occasionally ellipsoid, apically obtuse, constricted or attenuated; subterminal cells often wider, ca. 3–8 μm diam, always unbranched. Pileocystidia near the pileus margin mostly 2–4-celled, a few one-celled, terminal cells (10.2–)13–31–44(–75) × (3.8–)4.6–5.9–6.4(–7.1) μm, thin-walled, mainly cylindrical or subcylindrical, occasionally clavate, apically usually obtuse, contents with heteromorphous granulose, turning light ash black (#0d0d0d) in SV. Pileocystidia near the pileus center often smaller, 2–5-celled, thin-walled, terminal cells (13–)17–27–47(–70) × (4.0–)4.5–5.7–6.6(–7.9) μm, mainly clavate or cylindrical, contents granulose or occasionally crystalline. Cystidioid hyphae in subpellis and context with heteromorphous granulose contents, oleiferous hyphae in the subpellis close to the context.

Habitat and distribution:—Solitary and scattered in coniferous forests and mixed coniferous and broad-leaved forests of Pinus tabuliformis Carr. and Juglans mandshurica Maxim , in a warm temperate region of North China (Beijing and Hebei).

Additional specimens examined:— CHINA. Beijing, Pinggu District, Sizuolou Nature Reserve , 40.272411 N, 117.13521 E, elev. 222 m, 19 August 2020, coll. C. L. Hou , G. Q. Cheng and R. T. Zhang ( BJTC C381 ) .

Figures

FIGURE 3. Russula pseudosinoparva (BJTC L131). A–B. Basidiomes. C–D. SEM of basidiospores. Scale bar: A=1 cm, B=1 cm, C–D =1 μm. Photos by: Hao Zhou.

FIGURE 4. Microscopic features of Russula pseudosinoparva (BJTC L131). A. Basidia. B. Basidioles. C. Marginal cells. D. Hymenial cystidia on lamellae sides. E. Hymenial cystidia on lamellae edges. Scale bar: 10 μm. Drawings by: Hao Zhou.

FIGURE 5. Microscopic features of Russula pseudosinoparva (BJTC L131). A. Pileocystidia near the pileus margin. B. Hyphal terminations near the pileus margin. C. Pileocystidia near the pileus center. D. Hyphal terminations near the pileus center. Scale bar: 10 μm. Drawings by: Hao Zhou.