Nigromargarita tarda M. Y. Li & X. Sun 2025, sp. nov.

Nigromargarita tarda M. Y. Li & X. Sun sp. nov. Fig. 2 Etymology. Epithet derives from the slow growth rate of colonies on media. Description. Endophytic on healthy root of G. przewalskii. Teleomorph: undetermined. Anamorph: Hypha-branched, hyaline to brown, septate, thick-walled, verrucous. Conidiomata pycnidial, superficial, separated in aerial hyphae, globose, brown to dark-brown, unilocular, thin-walled, diameter 31–39 μm, not exceeding 50 μm. Pycnidial walls multi-layered of textura angularis cells. Conidiophore simple. Conidiogenous cells formed from the inner walls of the pycnidia, phialidic, determinate, cylindrical, straight or curved, monoblastic, hyaline, smooth, thin-walled. Conidia obovoid to clavate, hyaline, smooth, non-septate, 2.1–3.6 × 1.7–2.4 μm (x – = 2.93 × 1.95 μm, n = 20). Habitat. Healthy roots of Gymnocarpos przewalskii. Distribution. Minqin County, Wuwei City, Gansu Province, China. Culture characteristics. The colony diameters of H 331 colonies were 1.5 cm, 1.1 cm and 1.5 cm for OA, PDA and MEA, respectively, after 7 days of culture at 27 ° C in the dark. After 28 days, the colony diameters increased to 3.5 cm on OA, 2.6 cm on PDA and 3.4 cm on MEA, respectively. The colony on OA was superficial, circular with irregular margins, felt-like, white and brown in reverse. The colony on PDA was superficial, circular with regular margin, floccose to felt-like, greyish at the centre, brown at the margins and dark brown in reverse. The colony on MEA was submerged, brown with scarce aerial hyphae, circular in margin and brown in reverse (Fig. 2 H). The colony diameters of H 263 colonies were 1.2 cm, 0.8 cm and 1.1 cm for OA, PDA and MEA, respectively, after 7 days of culture at 27 ° C in the dark. After 28 days, the colony diameters increased to 4.0 cm on OA, 2.7 cm on PDA and 3.8 cm on MEA. The colony on OA was superficial, round, floccose to felt-like, central white, with wide concentric circles, regular dark brown margins and dark brown in reverse. The colony on PDA was superficial, circular in margin, greyish-green, velvety and dark brown in reverse, with brown pigmentation in the medium. The colony on MEA was superficial, circular at the margin, floccose to hairy, white to pale grey and light coloured in reverse (Fig. 2 H). Holotypus. China • Gansu Province, Wuwei City, Minqin County; on healthy roots of Gymnocarpos przewalskii; September 2019; M. Li (Holotype, HMAS 352979; ex-type CGMCC 3.27545). Paratypus. China • Gansu Province, Wuwei City, Minqin County; on healthy roots of Gymnocarpos przewalskii; July 2020; M. Li (Paratype, HMAS 352980; ex-paratype CGMCC 3.27544).