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

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Basidiodendron ruiliense Q. Yuan & C. L. Zhao sp. nov. Figs 21, 22, 23 Diagnosis. Basidiodendron ruiliense differs from other species by its farinaceous basidiomata and globose to subglobose basidiospores. Etymology. Ruiliense (Lat.). Referring to the type locality, Ruili, Yunnan Province, China. Type. CHINA • Yunnan Province, Dehong, Ruili City, Tongbiguan Provincial Nature Reserve, 24°11'N, 97°31'E, elevation 1,945 m asl., on fallen angiosperm branch, leg. C. L. Zhao, 21 Nov. 2024, CLZhao 41383 (SWFC 00041383, holotype). Description. Basidiomata annual, resupinate, closely adnate, farinaceous, without odor or taste when fresh, up to 12.5 cm long, 1.5 cm wide, and 100 µm thick. Hymenial surface smooth, white to cream when fresh, turning to cream upon drying. Sterile margin narrow, white, up to 1 mm. Hyphal system monomitic; generative hyphae with clamp connections, colorless, thin-walled, smooth, interwoven, 1.5–2.5 µm in diameter, IKI –, CB –; tissues unchanged in KOH. Leptocystidia subclavate, colorless, thin-walled, smooth, 18.5–27.5 × 4–6.5 µm. Hyphidia absent. Basidia ellipsoid to ovoid, longitudinally septate, two- to four-celled, 9.5–11.5 × 6–7.5 µm, involucres well developed, often totally covering basidial cells. Basidioles dominant, similar to basidia in shape, but slightly smaller. Basidiospores globose to subglobose, colorless, thin-walled, smooth, usually with one oil drop, IKI –, CB –, (4 –) 4.5–6 × 4–5.5 (– 5.5) µm, L = 5.13 µm, W = 4.98 µm, Q = 1.01–1.03 (n = 60 / 2). Additional specimen examined (Paratype). CHINA • Yunnan Province, Dehong, Mang City, Mengga Town, Tongbiguan Provincial Nature Reserve, 24°21'N, 98°05'E, elevation 2,107 m asl., on fallen angiosperm branch, leg. C. L. Zhao, 29 Jul. 2024, CLZhao 36504 (SWFC 00036504). Notes. Basidiodendron ruiliense formed a well-supported single lineage (100 % ML, 1.00 BPP) and grouped with B. fragilissimum and B. yunnanense in the phylogenetic inference using ITS + nrLSU + TEF 1 data (Fig. 2). However, B. fragilissimum can be delimited from B. ruiliense by its membranaceous basidiomata with a slightly olivaceous to slightly brown hymenial surface and shorter subclavate cystidia (9–15.5 × 2.5–5 µm vs. 18.5–27.5 × 4–6.5 µm). Basidiodendron yunnanense differs from B. ruiliense by its grayish-blue, reticulate to porulose hymenial surface (Duan and Zhao 2022). Morphologically, B. ruiliense resembles B. alni and B. mexicanum in having a smooth hymenial surface. However, B. alni differs from B. ruiliense by its waxy or partly gelatinized basidiomata. Basidiodendron mexicanum can be separated from B. ruiliense by its grayish to pale ochraceous hymenial surface and spiny, larger basidiospores (5.9–7.3 × 6.1–7.4 µm vs. 4.5–6 × 4–5.5 µm; Spirin et al. 2021).

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