Hysterodifractum D.A.C. Almeida, Gusmão & A.N. Mill., Phytotaxa 176(1): 304 (2014).
Index Fungorum number: IF 807155; Facesoffungi number: FoF 08058, 1 morphological species (Species Fungorum 2022), 1 species with molecular data.
Saprobic on twig. Sexual morph: Hysterothecia superficial, black, carbonaceous, navicular, straight or sometimes flexuous, with a longitudinal slit, smooth or slightly striated laterally, gregarious, lying at irregular angles. Pseudoparaphyses hyaline, apically branched, forming an epithecium above the asci. Asci bitunicate, cylindrical, 8-spored, uniseriate to irregularly biseriate. Ascospores pale brown, fusiform, smooth, disarticulating into part-spores. Asexual morph: Unknown (adapted from Almeida et al. 2014).
Type species: Hysterodifractum partisporum D.A.C. Almeida, Gusmão & A.N. Mill.
Notes: Hysterodifractum is characterised by superficial, black, carbonaceous hysterothecia, hyaline, apically branched pseudoparaphyses, cylindrical, 8-spored asci and pale brown, fusiform ascospores. Hysterodifractum differs from similar genera such as Rhytidhysteron in that the latter having ellipsoid, 3-septate dictyosporous ascospores usually with one longitudinal septum in the middle cell while H. partisporum has didymospores. Hysterodifractum is morphologically and phylogenetically a distinct genus in Hysteriaceae. Only LSU sequence data is available for H. partisporum.