Basidiodendron album Q. Yuan & C. L. Zhao 2026, sp. nov.

Résumé fourni par la source

Basidiodendron album Q. Yuan & C. L. Zhao sp. nov. Figs 3, 4, 5 Diagnosis. Basidiodendron album differs from other species in the genus by its smooth, white when fresh, white to cream upon drying hymenial surface and spiny, globose basidiospores. Etymology. Album (Lat.). Referring to the white basidiomata of the type specimen. Type. CHINA • Yunnan Province, Zhaotong, Xiaocaoba Town, Wumengshan National Nature Reserve, 27°77'N, 104°29'E, elevation 2,900 m asl., on fallen angiosperm branch, leg. C. L. Zhao, 21 Sep. 2023, CLZhao 33842 (SWFC 00033842, holotype). Description. Basidiomata annual, resupinate, closely adnate, membranous, without odor or taste when fresh, up to 6 cm long, 1 cm wide, and 50–100 µm thick. Hymenial surface smooth, white when fresh, white to cream upon drying. Sterile margin narrow, white, up to 1 mm. Hyphal system monomitic; generative hyphae with clamp connections, colorless, thin-walled, smooth, rarely branched, interwoven, 1.5–2.5 µm in diameter, IKI –, CB –; tissues unchanged in KOH. Leptocystidia clavate, colorless, thin-walled, smooth, 8.5–21.5 × 3–5.5 µm. Hyphidia arising from generative hyphae, nodulose, rarely branched, colorless, thin-walled, 1–2.5 µm in diameter. Basidia narrowly ovoid to ellipsoid, longitudinally septate, four-celled, 14–15.5 × 9–11.5 µm, involucres absent. Basidioles dominant, similar to basidia in shape, but slightly smaller. Basidiospores globose, colorless, thin-walled, spiny, usually with oil drops, IKI –, CB –, 7–9 (– 10) × (6 –) 6.5–8.5 (– 9) µm, L = 8.10 µm, W = 7.57 µm, Q = 1.07–1.12 (n = 60 / 2). Additional specimen examined (Paratype). CHINA • Yunnan Province, Zhaotong, Xiaocaoba Town, Wumengshan National Nature Reserve, 27°47'N, 103°51'E, elevation 1,650 m asl., on fallen angiosperm branch, leg. C. L. Zhao, 21 Sep. 2023, CLZhao 50615 (SWFC 00050615). Notes. The combined ITS + nrLSU + TEF 1 phylogenetic analysis revealed that Basidiodendron album (CLZhao 33842, CLZhao 50615) formed a single lineage with strong support (100 % ML, 1.00 BPP) and grouped with B. arachnoideum and B. spiculosum (L. S. Olive) Wojewoda (Fig. 2). However, B. arachnoideum can be distinguished from B. album by its arachnoid to farinaceous basidiomata with a grandinioid hymenial surface and its smaller basidiospores (3.5–4 × 3–3.5 µm vs. 7–9 × 6.5–8.5 µm). The key characters distinguishing B. spiculosum from B. album are its waxy basidiomata with a pruinose-reticulate hymenial surface and larger cystidia (28–51 × 6.8–10 µm vs. 8.5–21.5 × 3–5.5 µm; Spirin et al. 2021). Morphologically, B. album resembles three taxa, viz., B. alni Spirin & Malysheva, B. caucasicum Spirin, Malysheva & Kotiranta, and B. cinerellum (Bourdot & Galzin) Spirin & Malysheva, in having a smooth hymenial surface. However, B. alni differs from B. album by its pruinose basidiomata and smaller basidiospores (4.1–5 × 4.2–5 µm vs. 7–9 × 6.5–8.5 µm; Spirin et al. 2020). Basidiodendron caucasicum can be separated from B. album by its reticulate basidiomata and smaller basidiospores (4–5.1 × 3.4–4.5 µm vs. 7–9 × 6.5–8.5 µm; Spirin et al. 2020). Basidiodendron cinerellum is distinct from B. album in having pruinose-reticulate basidiomata and shorter basidiospores (4.9–7.2 × 5.2–7.7 µm vs. 7–9 × 6.5–8.5 µm; Spirin et al. 2021).

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.