Phanerochaete castanea K. Y. Luo, Yuan Yuan, Y. C. Dai & Xin Zhang 2024, sp. nov.

Phanerochaete castanea K. Y. Luo, Yuan Yuan, Y. C. Dai & Xin Zhang sp. nov. Figs 2, 3 Holotype. China • Zhejiang Province, Jinhua, Wuyi County, Niutoushan Forest Park; on a rotten bamboo; 17. VI. 2023; Y. C. Dai 24915 (BJFC 042468). Etymology. Castanea (Lat.) refers to the colour of new species’ basidiomata turning reddish brown in KOH. Description. Basidiomata annual, resupinate, adnate, soft coriaceous, without odor and taste when fresh, detachable from substrate, up to 2 cm long, 1.5 cm wide, 100–200 µm thick. Hymenial surface smooth, whitish to yellowish when fresh, yellowish brown upon drying, becoming reddish brown in KOH. Sterile margins paler than hymenial surface, thinning out, usually with whitish rhizomorphs, up to 0.2 cm. Hyphal system monomitic, generative hyphae mostly simple septate, occasionally with clamp connections, IKI –, CB –; tissue unchanged in KOH. Subicular hyphae hyaline, thick-walled, up to 0.1 µm thick, simple septate, occasionally bearing clamp connections, occasionally branched, parallel to interwoven, 3–5 µm in diameter. Subhymenial hyphae hyaline, thick-walled, clampless, 1.5–3 µm in diameter. Cystidia mostly subulate with a blunt or acute apex, 45–60 × 6–8 µm, hyaline, thick-walled, up to 0.1 µm thick, with a simple septum at the base, mostly encrusted with crystal granules at apical part, some with smooth apex, projecting up to 15 µm above the hymenial layer; cystidioles absent. Basidia clavate, with four sterigmata and a basal simple septum, 19–27 × 3–5.5 µm; basidioles of similar shape to basidia, but smaller. Basidiospores ellipsoid, hyaline, thin-walled, smooth, usually with one or two medium guttules, IKI –, CB –, (3.7 –) 3.9–5.1 (– 5.2) × (2.2 –) 2.3–3.1 µm, L = 4.45 μm, W = 2.66 μm, Q = 1.67–1.68 (n = 60 / 2). Type of rot. White rot. Additional specimen examined (paratype). China • Zhejiang Province, Jinhua, Wuyi County, Niutoushan Forest Park; on a rotten angiosperm wood; 17. VI. 2023; Y. C. Dai 24916 (BJFC 042469).