Setoseptoria bambusae J. Yang, Jian K. Liu & K.D. Hyde, sp. nov.

MycoBank number: MB 559452; Index Fungorum number: IF 559452; Facesoffungi number: FoF 12786;

Etymology: referring to the bamboo host

Holotype: HKAS 112629

Saprobic on submerged decaying bamboo culms. Asexual morph: Undetermined. Sexual morph: Ascomata scattered or gregarious, immersed under raised host tissue, perithecial, uniloculate to multi-loculate, 120–155 μm high, 280–330 μm diam., subglobose to conical, dark brown, ostiolate, surface view clypeus-like, with a small pore-like opening at the centre. Ostiole papillate, filled with pale brown to brown cells. Ascomatal wall coriaceous, 13–42 μm thick, consisting of multi-layered cells of textura angularis, with dark brown, larger polygonal, thick-walled cells of outer layers, cells becoming paler, smaller or elongated in inner layers. Hamathecium composed of abundant pseudoparaphyses, 2–3.8 µm wide, cylindrical, hyaline, septate, branched. Asci 130–180 × 14–16 µm ( = 155 × 15 µm, n = 20), bitunicate, fissitunicate, cylindrical to clavate, 8-spored, pedicellate, apex rounded with a minute ocular chamber. Ascospores 28–37 × 5.6–6.7 µm ( = 33.2 × 6.2 µm, n = 30), overlapping, biseriate, narrowly fusiform, hyaline, with a nearly median primary septum, 3-septate when mature, smooth-walled, guttulate, deeply constricted at the middle septum, straight or sometimes slightly curved, asymmetrical, often constricted at the upper middle part of the apical cell, surrounded by a large mucilaginous extended sheath.