Virosphaerella Videira & Crous, in Videira et al., Stud. Mycol. 87: 377 (2017).
Index Fungorum number: IF 822705; Facesoffungi number: FoF 08568, 2 morphological species (Species Fungorum 2022), 2 species with molecular data.
Pathogenic, producing leaf spots or not. Sexual morph: Ascomata amphigenous or epiphyllous, black, sub epidermal to erumpent, ovoid, globose or sub globose, apical ostiole, wall consisting of 2–3 layers of medium brown textura angularis. Asci aparaphysate, fasciculate, subsessile, subcylindrical to narrowly obovoid, straight to slightly curved, 8-spored. Ascospores bi- to tri-seriate, overlapping, hyaline, guttulate, thin-walled, straight to slightly curved, fusoid, fusoid-ellipsoidal with obtuse ends, medianly uniseptate or slightly longer in the basal cell, slightly constricted at septum, widest just above the septum, or in the middle of the apical cell, tapering toward both ends, but with more prominent taper towards lower end, mucilaginous sheath visible around spore. Ascospore germination from both ends in two patterns (remaining hyaline): Type I (Crous 1998), growing parallel to the long axis of the spore, with lateral branches parallel or perpendicular to the long axis of spore, irregular in width, constricted at the median septum of the spore, slightly distorting; Type B (Crous 1998), germ tube growing parallel to the long axis of the spore, regular in width, not distorting or becoming constricted at septum. Spermatogonia, when present, amphigenous, dark brown, subepidermal to erumpent, globose to subglobose. Spermatia hyaline, smooth, rod-shaped, with obtuse ends. Asexual morph: Unknown (adapted from Videira et al. 2017).
Type species: Virosphaerella pseudomarksii (Cheew., K.D. Hyde & Crous) Videira & Crous
Notes: Virosphaerella ascospore morphology is similar to that of Paramycosphaerella but differs by producing a discernable mucilaginous sheath around the ascospores (Cheewangkoon et al. 2008). Virosphaerella is currently, a distinct genus in Mycosphaerellaceae. Molecular markers available for Virosphaerella are ITS, LSU, Actin, BTUB, Calmodulin, RPB2 and TEF-1.