Nigroporus austroasianus Y. C. Dai, X. L. Li & Yuan Yuan sp. nov.

Figs 5, 6

Holotype.

China • Yunnan Province, Mengla County, Shangyong Nature Reserve, on rotten angiosperm wood, 20 August 2019, Dai 20632 (BJFC 032299).

Etymology.

Austroasianus (Lat.): refers to the distribution of the species in South Asia.

Description.

Basidiomata. Annual, pileate, a few imbricate, leathery and without odor or taste when fresh, becoming corky and light in weight upon drying. Pilei semicircular to spathulate, projecting up to 4 cm, 6 cm wide and 1.4 mm thick at center. Pileal surface grayish violet to dark violet when fresh, becoming grayish brown upon drying; margin thin and sharp, usually lobed. Pore surface flesh pink to lavender when fresh, becoming fawn when bruised, pale mouse gray when dry, sterile margin distinct, cream when dry, up to 1.1 mm wide; pores round to angular, 10–13 per mm; dissepiments thin, entire to lacerate. Context vinaceous to reddish brown, corky when dry, up to 0.4 mm thick. Tubes concolorous with pore surface, corky when dry, up to 1 mm long.

Hyphal structure. Hyphal system dimitic; generative hyphae bearing clamp connections; skeletal hyphae IKI –, CB –; tissues darkening in KOH.

Context. Generative hyphae frequent, hyaline to pale yellow, thin- to slightly thick-walled, occasionally branched, 2–4 µm in diam.; skeletal hyphae dominant, pale yellow, thick-walled with a wide lumen, unbranched, slightly flexuous, interwoven, 2.5–4 µm in diam.

Tubes. Generative hyphae dominant, hyaline, thin-walled, occasionally branched, 2.5–4.5 µm in diam.; skeletal hyphae pale yellow, slightly thick-walled with a wide lumen, unbranched, slightly flexuous, interwoven, 3.5–6.5 µm in diam. Cystidia and cystidioles absent. Basidia pyriform to barrel-shaped, with four sterigmata and a basal clamp connection, 7–12 × 3.5–4.5 µm. Basidioles barrel-shaped, smaller than basidia.

Spores. Basidiospores allantoid, hyaline, thin-walled, smooth, occasionally with one or two small guttules. IKI –, CB –, (2.1 –) 3–4.1 (– 4.2) × (1.1 –) 1.5–2 (– 2.2) µm, L = 3.21 µm, W = 1.63 µm, Q = 1.83–2.01 (n = 90 / 3).

Additional specimen examined

(paratype). China • Guangxi Zhuang Autonomous Region, Leye County, Yachang Orchid Nature Reserve, stump of Pinus yunnanensis, 29 June 2024, Dai 28512 (BJFC 048771) . Malaysia • Selangor, Kota, Damansara, Community Forest Reserve, on rotten angiosperm wood, 16 April 2018, Dai 18594 (BJFC 026882) .