Gymnopus pseudoandrosaceus Chun Y. Deng, J.P. Li & Antonín, 2025

Deng, Chun-Ying, Wang, Wang-Kun, Li, Ji-Peng & Antonín, Vladimír, 2025, Morphology and phylogeny reveal Gymnopus pseudoandrosaceus sp. nov. (Agaricales, Basidiomycota) from Southwest China, Phytotaxa 683 (3), pp. 218-228 : 223

Gymnopus pseudoandrosaceus Chun Y. Deng, J.P. Li & Antonín , sp. nov. Figs. 1–2

Fungal Names number: FN 571979

Etymology: —From Latin, “pseudo” means similar to; pseudoandrosaceus refers to the new species’ resemblance to G. androsaceus .

Holotype: — CHINA. Guizhou, Zunyi City, Fuyan Town , 107°16′11″E, 28°31′37″N, elev. 1397.96 m, fallen twigs of a broadleaved tree, 10 May 2023, LHF1475 (HGASMF01-23515).

Diagnosis:—Characterized by the marasmioid basidiomata, brown pileus and lamellae colors, striate pileus, adnate to subdistant lamellae, black stipe, well-developed rhizomorphs, repent pileipellis hyphae and diverticulate cheilocystidia. Differs from Gymnopus androsaceus in having a shining black stipe and robust rhizomorphs, narrow, thick, and crowded lamellae; a cutis pileipellis without broom cells and with encrusting brown pigments.

Description:—Pileus 8–15 mm diam, broadly convex, expanding to plano-convex, striatulate; membranous, surface dull, dry, velutinous, brownish orange (6D6,7D 8,7E 8) with a dark, light brown to dark brown (7F8) umbo. Context 0.5 mm thick, brown. Lamellae adnexed to shallowly adnate, crowded (L = 24–35), lamellulae l = 4–5, narrow (1–1.5 mm), sometimes forked or anastomosing, light brown (6D6,7D8), non-marginate, concolorous with pileus. Stipe 7–14 × 0.5–1 mm, central, cylindrical, filiform, horse-hair like, tough, smooth, glabrous, insititious, dark brown (7F8), arising from woody substrates or directly from rhizomorphs. Rhizomorphs black, glabrous, common, long, branched or unbranched, 0.5‒1 mm thick. Odor indistinct.

Basidiospores 6.4–9.8(–10.9) × (3.0‒) 3.1–4.7(‒5.0) μm (average = 8.13 × 3.63 μm, E = (1.84–)1.87–2.55(‒2.78), Qm = 2.23±0.20), ellipsoid to oblong, inamyloid, hyaline. Basidia (20)24.5–37(‒38.2) × 5–7.6(‒9) μm, 2- or 4-spored, clavate, cylindrical. Basidioles 20.8–34(‒36) × (3.5‒)4.5–6.8(‒8) μm, fusiform, clavate, cylindrical. Cheilocystidia (8‒)10–38 × 2.5–9(‒10) μm, irregularly clavate, lobed to irregularly branched, with conical or apical projections. Pleurocystidia absent. Pileipellis a cutis of encrusted hyphae, sometimes with some lobed structures, 4–8 μm broad, broom cells not found. Stipitipellis a cutis composed of cylindrical, thin-walled, hyaline, parallel-arranged hyphae, dextrinoid, smooth. Caulocystidia absent. Clamp connections present in all tissues.

The mycelium was isolated from the fruiting bodies. The purified culture consists of white hyphae. Hyphae growth rate was nearly 1 cm. d-1, the plate showed the mycelium growing on the fifth day.

Ecology: —Saprotrophic, gregarious, usually arising on dead twigs or branches in broadleaf forests.

Additional specimens examined:— CHINA. Guizhou Province, Zunyi City, Fuyan Town Nature Reserve, 28°45′51.8″N, 107°16′12″E, elev. 1378.83 m, on dead branches of a broadleaved tree, 6 May 2023, Chunying Deng dcy5702 (HGASMF01-23386), dcy5687 (HGASMF01-23605).

Figures

FIGURE 1. Maximum-likelihood (ML) tree based on ITS and LSU listed on Tabel 1 sequence from Gymnopus spp. and outgroup Paragymnopus spp. The Bootstrap percentages (BS) from the maximum-likelihood analysis ≥70% were shown around the nodes.

FIGURE 2. Gymnopus pseudoandrosaceus a–c. Basidiomata (a. lhf1475 holotype; b. dcy5687; c. dcy5702), d. strains isolated from basidomata lhf1475, e. pileipellis, f. cheilocystidia, i. basidia, j. basidiospores. a–c = 1 cm and e–j = 10 µm.