Acrocalymma Alcorn & J.A.G. Irwin, Trans. Br. Mycol. Soc. 88(2): 163 (1987).
MycoBank number: MB 11008; Index Fungorum number: IF 11008; Facesoffungi number: FoF 07097; 7 morphological species (Species Fungorum 2020), 7 species with molecular data.
Type species – Acrocalymma medicaginis Alcorn & J.A.G. Irwin.
Notes – Alcorn & Irwin (1987) introduced Acrocalymma with A. medicaginis as the type species. Shoemaker et al. (1991) reported A. medicaginis as the asexual morph of Massarina walkeri. However, Trakunyingcharoen et al. (2014) showed that M. walkeri and A. medicaginis are phylogenetically distinct although congeneric, thus, introducing the new combination, A. walkeri. In their phylogenetic analyses, the type species of Rhizopycnis resides in Acrocalymma sensu stricto and hence, Rhizopycnis has been treated as a synonym of Acrocalymma (Trakunyingcharoen et al. 2014).
Species in this genus occur in terrestrial habitats apart from Acrocalymma aquatica (Zhang et al. 2012a). Except for the pathogenic species A. medicaginis and A. vagum, the genus has been reported as saprobes e.g. A. fici on Ficus sp. and A. cycadis on Cycas calcicola (Crous et al. 2014a, Trakunyingcharoen et al. 2014).