Halobyssothecium aquifusiforme J. Yang, Jian K. Liu& K.D. Hyde, sp. nov.
MycoBank number: MB 559450; Index Fungorum number: IF 559450; Facesoffungi number: FoF 12783;
Etymology: referring to the aquatic habitat of the fungus and fusiform ascospores.
Holotype: HKAS 112638
Saprobic on submerged decaying wood. Asexual morph: Undetermined. Sexual morph: Ascomata scattered or gregarious, immersed, perithecial, 220–350 μm high, 160–350 μm diam., subglobose, dark brown, ostiolate, with conidial masses at the apex of the short neck. Ascomatal wall coriaceous, 8–26 μm thick, consisting of multi-layered cells of textura angularis, outer layers with brown, polygonal, thick-walled cells, inner layers with pale brown to hyaline, polygonal to elongated, thin-walled cells. Hamathecium composed of 1.2–2.2 µm wide, cylindrical, hyaline, septate, branched pseudoparaphyses. Asci 110–158 × 14.7–20.8 µm ( = 134 × 17.6 µm, n = 20), bitunicate, cylindrical, rounded at the apex with an ocular chamber, 8-spored, straight, or slightly flexuous, with a short pedicel. Ascospores 26.7–32.8 × 7.8–9.7 µm ( = 29.8 × 8.7 µm, n = 30), overlapping, obliquely biseriate, narrowly fusiform with obtuse ends, yellowish brown, 3-septate, smooth-walled, guttulate, deeply constricted at the septum.