Scleroderma plutonium Kun L. Yang, Jia Y. Lin, Zhen-Chao Liu & Zhu L. Yang 2025, sp. nov.

(1.6) Scleroderma plutonium Kun L. Yang, Jia Y. Lin, Zhen-Chao Liu & Zhu L. Yang, sp. nov. (Fig. 8) Registration identifier:— FN572385 Etymology:— Referring to the color of this fungus like the Pluto. Diagnosis:— Differing from other species in sect. Scleroderma known in Asia by the tiny to small, yellowish to orangish basidiomata. Type:— China, Guangdong Province, Guangzhou City, Huangpu District, Jiangdong Village, Boluoshan Hill, 23°11'32"N, 113°32'25"E, elevation 150 m, August 21, 2023, Zhen-Chao Liu, Jia Y. Lin & Kun L. Yang, S23481 (HKAS145949, holotype (deposited in the Herbarium of Cryptogams in Kunming Institute of Botany of Chinese Academy of Sciences; ITS: PV059135; nrLSU: PV054256); HTBM1592, isotype). Description:— Basidiomata tiny to small, 4–14 mm in diameter, 3–11 mm in height, subglobose, sessile; odor fungal; taste unknown. Peridium leathery, 0.25–0.5 mm thick, beach yellow (#F9F3C9) to pale dirty orange (#FAF4E3), without a color change or turning reddish after damaged, with minute, dull dirty orange (#EBD087) to light brown (#B39966) squamules to nearly smooth. Gleba compact at first, becoming pulverulent, flint brown (#736960) to dull black (#0B0C0E). Basal rhizomorphs abundant, whitish. Basidiospores {40/1/1} 12–14.5 (15) [13.25 ± 0.76, 13.00] µm in diameter including ornamentation, mostly globose, rarely subglobose, thick-walled, with verrucose to echinulate ornamentation 0.5–1 µm high, brownish to purplish, often surrounded by remnants of placental cells. Basidia collapsed. Gleba trama composed of 2–4.5 μm wide, thin-walled to slightly thick-walled, nearly colorless to slightly brownish, compact, moderately branching, subregularly arranged to interwoven hyphae without clamp connections. Peridial squamules composed of 3–5.5 μm wide, slightly thick-walled, brownish, moderately compact, moderately to frequently branching, subregularly arranged to interwoven hyphae without clamp connections. Peridial trama composed of 3–6.5 μm wide, slightly thick-walled, nearly colorless to slightly brownish, compact, moderately to frequently branching, subregularly arranged to interwoven hyphae without clamp connections. Habits and distribution:— Gregarious, on soil, in subtropical forests, associated with plants of Fagaceae. Currently known from Asia (China) with molecular evidence. Notes:— According to the phylogenetic position, this species may be poisonous to cause gastroenteritis and psycho-neurological disorder.