Mucomycosphaerella Quaedvl. & Crous, in Quaedvlieg et al., Persoonia 33: 22 (2014).
Index Fungorum number: IF 807791; Facesoffungi number: FoF 09726, 1 morphological species (Species Fungorum 2022), 1 species with molecular data.
Foliicolous. Sexual morph: Ascomata pseudothecial, depressed ellipsoidal, immersed becoming erumpent, with central ostiole lacking periphyses, brown, dark brown at the ostiole, solitary or in clusters of two or more joined together; wall of textura angularis, consisting of 4–6 layers at the top, but only 2–3 layers at the sides and bottom. Hamathecium sparse, composed of branched and anastomosing septate pseudoparaphyses embedded in a gelatinous matrix. Asci ellipsoidal to ovoid, 8-spored, indistinctly pedicellate, bitunicate, fissitunicate, thick-walled, with a thin, tough ectotunica and a thick gelatinous, expanding endotunica. Ascospores bi- to triseriate, elongate ellipsoidal, sometimes inequilateral,uniseptate, with one additional pseudoseptum in each cell, slightly constricted at the septum, hyaline, guttulate, surrounded by a gelatinous sheath that is constricted around the septum. Asexual morph: Unknown (adapted from Quaedvlieg et al. 2014).
Type species: Mucomycosphaerella eurypotami (Kohlm., Volkm.-Kohlm. & O.E. Erikss.) Quaedvl. & Crous 2014
Notes: Mucomycosphaerella differs from Mycosphaerella s. str.in having well developed, persistent mucoid sheaths around its ascospores, and the absence of Ramularia asexual morphs. Mucomycosphaerella is unique in having a depressed ascomata, a pale, thin-walled lower half, and a hamathecium of loosely branched, anastomosing hyphae in a hymenial gel, with hyaline ascospores. M. eurypotami was previously included in Mycosphaerella. A formal revision of the genus was done by Kohlmeyer et al. (1999) and the type species was epitypified by Verkley et al. (2004). Crous et al. (2007b, 2009b) segregated various allied genera and families within Mycosphaerella s. str. Mucomycosphaerella is a distinct genus in the Capnodiales. Hongsanan et al. (2020a) included Mucomycosphaerella in Capnodiales, genera incertae sedis. Molecular markers available for Mucomycosphaerella are LSU, SSU, RPB2 and mtSSU.