Henningsomyces bambusae S. Y. He, H. M. Zhou & C. L. Zhao 2025, sp. nov.

Henningsomyces bambusae S. Y. He, H. M. Zhou & C. L. Zhao sp. nov. Figs 6, 7 Diagnosis. Henningsomyces bambusae differs from H. candidus by its globose to subglobose and wider basidiospores (6.5–8.5 µm vs. 4–5 µm). Holotype. China • Yunnan Province, Zhaotong, Wumengshan National Nature Reserve, GPS coordinates 27°29'N, 103°55'E, evel. 1900 m asl., on dead bamboo, leg. C. L. Zhao, 18 September 2023, CLZhao 33088 (SWFC). Etymology. Bambusae (Lat.) refers to the host genus Bambusa. Basidiomata. Basidiomes forming loosely scattered colonies, short cylindric to tubular, sessile, up to 1–1.6 cm in length, 0.5–1 cm diam; external surface white (60) to cream (4 A 2 / 3), finely tomentose when dry; inner surface covered by a deeply concave, smooth hymenium. Hyphal structure. Monomitic, generative hyphae with clamp connections and simple septa, thin- to thick-walled, IKI –, CB –; tissues unchanged in KOH. External hyphae slightly contorted, widest at the base, slightly tapering towards the obtusely rounded apex, hyaline, thick-walled to solid, occasionally with simple septa, frequently unbranched, dextrinoid, CB –, 3–4 μm diam; tramal hyphae hyaline, thin-walled, with clamp connections, IKI –, 2.5–3 µm diam. Cystidia absent. Basidia cylindrical to subcylindrical, hyaline, thin-walled, with two sterigmata and a basal clamp connection, 19.5–22.5 × 7–8.5 µm; basidioles in shape similar to basidia, but slightly smaller. Spores. Basidiospores globose to subglobose, hyaline, thin-walled, smooth, with guttules, IKI –, CB –, 6.5–8.5 (– 9) × (6 –) 6.5–8.5 (– 9) µm, Lm = 7.61 µm, Wm = 7.45 µm, Q = 1.02–1.04 (n = 60 / 2). Additional specimens examined (paratypes). China • Yunnan Province, Zhaotong, Wumengshan National Nature Reserve, GPS coordinates 27°29'N, 103°55'E, evel. 1900 m asl., on a dead bamboo, leg. C. L. Zhao, 18 September 2023, CLZhao 33024; CLZhao 33085 (SWFC). Notes. Based on the ITS analysis (Fig. 2), the new taxon Henningsomyces bambusae grouped within the genus Henningsomyces and formed a sister group with H. candidus (Pers.) Kuntze. However, H. candidus can be delimited from H. bambusae by its narrower basidiospores (4–5 μm vs. 6–8 μm; Gilbertson and Blackwell 1985).