Hysterium Pers., Tent. disp. meth. fung. (Lipsiae): 5 (1797).

Index Fungorum number: IF 2464; MycoBank number: MB 2464; Facesoffungi number: FoF 0004; 47 morphological species (Species Fungorum 2020), 16 species with molecular data.

Type speciesHysterium pulicare Pers.

Notes – A historical overview of the nomenclature of Hysterium was presented in Boehm et al. (2009a). This genus is characterised by three- or more transversely-septate, pigmented versicolorous or concolorous asymmetric phragmospores, borne in hysterothecia Boehm et al. (2009a, b).

Key to four species of Hysterium
1. Ascospore size more than 100 μm ………………………………… …………………………………………….Hysterium centramurum
1. Ascospore size less than 100 μm …………………………………………………………………………………. 2
2. Ascospore size equal or less than 60 μm ……………………………………………………………………… Hysterium thailandica
2. Ascospore size more than 60 μm ………………………………………………………………………………… 3
3. 1-septate, under different stains appears subdivided into numerous compartments ……….. Hysterium curtisii
4. 1-3 septate, germinated spores appear 3-septate …………………………………………………………. Hysterium doimaeensis