Hysterodiscula Petr., Bot. Arch. 43: 210 (1942) 
Ascomycota, genera incertae sedis
Saprobic on the host plant in terrestrial habitats, such as Empetrum nigrum (Ericaceae), E. hermaphroditicum (Sutton 1980). Sexual morph: undetermined. Asexual morph: Conidiomata black, stromatic, pycnidial, solitary to gregarious or confluent, immersed, elongated or irregular in shape, irregularly multilocular, glabrous. Ostiole absent, dehiscence by longitudinal fissures in the upper wall. Conidiomatal wall composed of thin-walled, pale brown to hyaline cells of textura angularis in the basal and lateral part, becoming thicker, dark brown cells in the upper part. Conidiophores arising all around the locular cavity, hyaline, cylindrical, branched at the base, septate, with acrogenous conidia. Conidiogenous cells hyaline, holoblastic, cylindrical, integrated or discrete, determinate, smooth-walled. Conidia hyaline, cylindrical to clavate, obtuse at apex, narrow and truncate at base, unicellular, smooth-walled.
Type species: Hysterodiscula empetri Petr., Bot. Arch. 43: 211 (1942) 
Notes: Petrak (1942) found that Melasmia empetri Magnus differs from typical members of the genus in form of conidiomata, conidiophores and conidia. He proposed a new genus Hysterodiscula to accommodate this species and another species H. kalmiae. Sutton (1980) re-described and illustrated H. empetri and provided a detailed description for the genus. The sexual morph of H. empetri has been assigned to Duplicaria empetri (Pers.) Fuckel (type species of Duplicaria Fuckel) by several authors (Lind 1913, Nannfeldt 1932, Darker 1967, Dennis 1968). However, Powell (1973) rejected the connection of M. empetri with D. empetri. Wijayawardene et al. (2017b) accepted only H. kalmiae Petr. in the genus. We accept two species in the genus, which has not been studied with molecular data.
Distribution: Finland, France, Germany, Latvia, Sweden (Sutton 1980).
Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD (2020) Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–801.