Ceratosphaeria flava J. Yang, E.B.G. Jones & K.D. Hyde, sp. nov.

MycoBank number: MB 559711; Index Fungorum number: IF 559711; Facesoffungi number: FoF 12825, Fig. 80

Etymology: referring to the yellow ascospores.

Holotype: MFLU 15-1171

Saprobic on decaying wood submerged in freshwater. Asexual morph: Undetermined. Sexual morph: conspicuous as yellow necks on the host surface and masses of pale pink asci on the apex of neck. Ascomata solitary or in small groups, immersed, perithecial, 200–300 × 300–500 μm, globose to subglobose, brown to yellowish brown, ostiolate, with a long yellow neck, ascospore mass pink to pale orange. Ostiole periphysate. Ascomatal wall coriaceous, 7–20 μm thick, 2-layered, outer layer consisting of multi-row of brown, polyhedral cells of textura angularis, less distinguished from the host tissue; inner layer consisting of pale brown to hyaline, elongated, thin-walled cells of taxtura prismatic. Paraphyses abundant, persistent, septate, hyaline, unbranched, guttulate, tapering towards the apex, up to 200 µm long, (5–)8–12 μm wide near the base, slightly constricted at the septa. Asci (105–)120–140(–150) × (6–)8–11(–12) µm ( = 130 × 9 µm, n = 30), cylindrical, straight, or slightly curved, obtuse at the apex, 8-spored, with a non-amyloid apical ring. Ascospores 100–120 × 1.5–3 µm ( = 110 × 2.3 µm, n = 30), parallel, filiform, straight or curved, hyaline, multi-septate, smooth-walled, guttulate, thin-walled.