Index Fungorum number: IF557044, Facesoffungi number: FoF02361; Fig. 2

Etymology: In reference to the hyaline conidia.

Holotype: HKAS 105140.

Saprobic on decaying wood. Sexual morph undetermined. Asexual morph hyphomycetous. Colonies effuse, black, hairy; under a dissecting microscope the upper part of each conidiophore is seen to be covered with a white powdery mass of conidia. Mycelium partly superficial, partly immersed. Conidiophores 40.0–145.0 × 2.0–3.5 μm (av. = 90.0 × 2.5 μm, n = 25), macronematous, caespitose, closely packed together but not forming synnemata, unbranched, sometimes branched, straight or flexuous, smooth-walled, thin-walled, aseptate to septate, cylindrical, subulate, dark brown at the base, paler towards the apex, rarely reduced to conidiogenous cells. Conidiogenous cells 23.0–115.0 × 1.5–3.0 μm (av. = 48.0 × 2.0 μm, n = 25), polyblastic, integrated, terminal becoming intercalary, cylindrical, tapering apically, sympodial, with numerous indistinctive denticles, hyaline to pale brown. Conidia 2.0–3.7 × 1.8–2.6 μm (av. = 2.8 × 2.1 μm, n = 40), solitary, acropleurogenous, simple, dry, smooth, thin-walled, aseptate, hyaline, ellipsoidal to obovoid.

Culture characteristics: Conidia germinating on WA within 96 h. Colonies on PDA circular, white-brown, reaching a diam. of 1.5–2 cm in 40 days at 28°C.

Material examined: CHINA. Guizhou Province: Qiannan Buyi Miao Autonomous Prefecture, Dushan County, Guizhou Zilinshan National Forest Park (Shengou District), on decaying wood, 6 July 2018, Chuan-Gen Lin, DS 1-46 (HKAS 105140, holotype; MFLU 19–2848, isotype), ex-type living culture GZCC 18-0056; ibid., DS 1-66 (HKAS 105149, paratype; MFLU 19–2849), living culture GZCC 18-0066.

Notes: Rhamphoriopsis hyalospora differs from other Rhamphoriopsis species by its caespitose, subulate conidiophores closely packed together but not forming synnemata, and producing aguttulate, aseptate, hyaline conidia. Phylogenetically, two isolates of Rhamphoriopsis hyalospora form a separate clade (Fig. 1) and it can be recognized as phylogenetically distinct species and we introduce it as new species in this study.