Russula purpureogrisea J. Q. Yan, B. J. Zhong & S. N. Wang sp. nov.
Fig. 2
Diagnosis.
Russula purpureogrisea is mainly characterised by its small to medium-sized basidiomata, a dark greyish-ruby to greyish-brown pileus, unforked and rather crowded lamellae with 14–15 per cm at the margin and lamellulae 1 / 5 to 3 / 4 of the lamellae length, basidiospores with ornamentation composed mostly of obtuse-conical isolated warts, occasionally connected by fine lines or low ridges, occasionally forming a subreticulum locally, subcylindrical to clavate pleurocystidia with obtuse or acute apices and frequent papillae, subcylindrical to clavate cheilocystidia with obtuse or acute apices and occasional papillae, and cylindrical or clavate pileocystidia with frequent papillae.
Holotype.
China • Hubei Province, Yichang City, Xingshan County, Heyuan, 31°28'10"N, 110°50'49"E, alt. 491 m, 23 Jul 2024, Jun-Qing Yan, Lin-Gen Chen, Ling Ding and Hong Chen (HFJAU 5642).
Etymology.
‘ purpureogrisea’ refers to a purplish-gray pileus.
Chinese name.
紫灰红菇.
Description.
Basidiomata small to medium-sized. Pileus 20–50 mm in diameter, hemispherical when young, plano-convex and depressed in the centre when mature; surface dry, smooth, glabrous; dark greyish ruby (12 E 3) when young, becoming greyish brown (9 F 3) at the centre in age, paler towards the margin. Lamellae 1.5–3.0 mm wide, sinuate, without furcations, rather crowded, 14–15 per cm near pileus margin; lamellulae present, 1 / 5 to 3 / 4 of the lamellae length, white (1 A 1). Stipe 26–37 × 7.5–10.0 mm, cylindrical, central, solid, white (1 A 1). Context thick, white (1 A 1), unchanging when bruised; taste and odour not recorded.
Basidiospores (6.1 –) 6.6–8.1 (– 8.4) × (5.2 –) 5.3–6.6 (– 6.8) μm, Q = (1.01 –) 1.14–1.29 (– 1.30), globose, subglobose or broadly ellipsoid; ornamentation composed mostly of obtuse-conical isolated warts, moderately dense (3–5 in a 3 μm diam. circle), occasionally connected by fine lines or low ridges, occasionally forming a subreticulum locally, warts 0.2–0.6 μm high. Basidia 39.5–49.5 × 10.0–12.5 μm, clavate, 2 - or 4 - spored. Hymenial cystidia on lamellae sides 47.0–76.0 × 6.5–10.0 μm, subcylindrical to clavate, apically obtuse or acute, often with a papilla, with contents, thin-walled, contents heteromorphous, turning greyish-black in sulphovanillin. Hymenial cystidia on lamellae edges 39.5–55.5 × 5.5–9.5 μm, subcylindrical to clavate, apically obtuse or acute, with occasional papillae, contents heteromorphous, turning greyish-black in sulphovanillin. Pileipellis metachromatic in cresyl blue, distinctly two-layered, ca. 120–190 μm thick; suprapellis 50–75 μm deep, composed of slender, erect to repent hyphae that are attenuated at the apex; subpellis 70–115 μm deep, composed of interwoven hyphae. Hyphal terminations near the pileus margin thin-walled, often flexuous, sometimes forked; terminal cells 9.5–22.5 × 2.0–4.0 μm, subcylindrical, apically attenuated or constricted. Hyphal terminations near the pileus centre similar to those near the margin; terminal cells 12.5–23.5 × 2.0–3.5 μm, subcylindrical, apically obtuse or attenuated. Pileocystidia near the pileus margin 18.5–31.5 × 3.0–6.5 μm, clavate or cylindrical, apically obtuse or acute, often with a papilla, thin-walled; contents granular, turning greyish-black in sulphovanillin. Pileocystidia near the pileus centre 18.5–33.5 × 3.0–4.5 μm, clavate or cylindrical, apically obtuse or acute, often with a papilla, thin-walled; contents granular, turning greyish-black in sulphovanillin. Cystidioid hyphae in pileipellis and context with heteromorphous or crystalline contents; oleiferous hyphae in subpellis with refractive contents.
Habitat.
Mixed coniferous and broad-leaved forest dominated by Cupressaceae, Pinaceae, Theaceae, and Fagaceae.
Additional specimens examined.
China • Hubei Province: Yichang City, Xingshan County, Heyuan, 31°28'10"N, 110°50'49"E, alt. 491 m, 23 July 2024, Jun-Qing Yan, Lin-Gen Chen, Ling Ding and Hong Chen, HFJAU 5628.
Notes.
Based on morphological characteristics such as small to medium-sized basidiomata, a dark greyish-ruby to greyish-brown pileus, the presence of lamellulae, basidiospores with an inamyloid suprahilar plage, a pileipellis that is metachromatic in cresyl blue, and the presence of unicellular pileocystidia, this species is assigned to subgenus Heterophyllidiae subsection Cyanoxanthinae. Phylogenetically, this species shares the highest ITS sequence similarity with R. perviridis (95 %), R. nigrovirens (94 %), and R. cyanoxantha (93 %). It also shares LSU sequence similarities in the range of 96 % – 98 % with R. variata Banning, R. parvisaxoides (T. Lebel) T. Lebel, and R. banwatchanensis Sommai. However, R. perviridis has a greyish-green to dark green pileus, lamellae turning yellowish-brown when bruised, and longer pileocystidia (36.5–60.0 μm) (Chen et al. 2024 a). Russula nigrovirens has a dark green pileus, wider basidiospores (up to 8 μm), and longer pileocystidia (up to 62.0 μm) (Zhao et al. 2015). Russula cyanoxantha has a greenish-purple pileus, larger basidiomata (pileus diameter up to 12 cm), and longer hymenial cystidia (up to 100 μm) (Bon 1988; Sarnari 1998). Russula variata features lamellae turning rust-brown when bruised, spore ornamentation arranged in chains and connected into ridges, and narrower basidia (7–8.5 µm) (Sarnari 1998). Russula parvisaxoides forms sequestrate basidiomata with a white surface bearing pale yellow to orange-brown patches, and longer basidiospores (up to 11 μm) (Lebel 2002). Russula banwatchanensis has longitudinal striations on the stipe, lower spore ornamentation (not exceeding 1.0–2.0 μm), and longer pileocystidia near the margin (42.5–127.5 μm) (Crous et al. 2022).
Morphologically, only R. brunneoviolacea Crawshay, R. phloginea, and R. pseudocyanoxantha Paloi are quite similar to this species, as all share purplish pileus tones, basidiospore sizes ranging from 6.0–9.0 × 5.0–7.0 μm, and subcylindrical or clavate hymenial cystidia. However, R. brunneoviolacea has a stipe that turns yellow locally when bruised, higher spore ornamentation (1–1.6 μm), and wider pileocystidia (up to 9 μm) (Sarnari 1998). Russula phloginea features small white crust-like warts or saddle-brown thin scales on the pileus and longer pileocystidia (up to 56 μm) (Song et al. 2019). Russula pseudocyanoxantha has a hollow stipe that turns pale yellow when bruised, and spore ornamentation composed of completely isolated warts without any connections (Khatua et al. 2021 b).
Publication Date: 2026-06-23