Resupinatus tropicus Q. X. Guan, H. Zhao & Y. C. Dai sp. nov.

Figs 3 a, b, 4, 5

Holotype.

China • Hainan Province, National Park of Hainan Tropical Rainforest, Baisha County, Qingsong, on fallen angiosperm branch, 19.116649°N, 109.265192°E, elev. 420 m, 24 November 2024, Dai 30226 (BJFC 050485).

Etymology.

Tropicus (Lat.) refers to the new species found from tropical China.

Description.

Basidiomata annual, sessile, gelatinous, flabelliform or occasional suborbicular, laterally or dorsally attached to substrate, fragile and watery when fresh, becoming firm-gelatinous when dry. Pileus orbicular when juvenile, becoming flabelliform when mature, upper surface pale mouse gray when fresh, becoming dark gray to black when dry, smooth, up to 10 mm in diam.; margin unrolled to incurved when juvenile, becoming straight, entire. Hymenium lamellate, lamellae with different lengths. Stipe absent. Context dark brown to black, leathery when dry, up to 0.3 mm thick.

Hyphal system monomitic; generative hyphae with clamp connections, colorless, thin- to thick-walled, branched, interwoven, 1–2 µm in diameter. Cheilocystidia clavate to cylindrical with irregular, bifurcate, multifurcate, or rarely nodulose, thin-walled, colorless, 11–16 × 4–6.5 µm, arising from generative hyphae. Pleurocystidia fusiform to with branched apices, 13–18 × 2–4 µm. Basidia clavate, with four sterigmata and a basal clamp connection, with a few guttules, 13–17 × 3.5–4.5 µm; basidioles similar to basidia, but slightly smaller. Basidiospores cylindrical to oblong-ellipsoid, colorless, thin-walled, smooth, with a few guttules, IKI –, CB –, 4.4–5.2 (– 5.5) × 2.4–2.9 µm, L = 4.78 µm, W = 2.64 µm, Q = 1.81 (n = 30 / 1).

Type of rot.

white rot.

Additional specimen examined

(paratype). China • Hainan Province, National Park of Hainan Tropical Rainforest, Baisha County, Qingsong, on fallen angiosperm branch, 19.116649°N, 109.265192°E, elev. 420 m, 24 November 2024, Dai 30251 (BJFC 050510).