Pyrenidium Nyl., Flora, Regensburg 48: 210 (1865).
MycoBank number: MB 4578; Index Fungorum number: IF 4578; Facesoffungi numbers: FoF 07909; 13 morphological species (Species Fungorum 2020), 3 species with molecular data.
Type: Pyrenidium actinellum Nyl.
Notes: Pyrenidium was placed in Dacampiaceae based on morphology and the environmental habitats (Hyde et al. 2013; Wijayawardene et al. 2014a, 2018; Jaklitsch et al. 2016). Crivelli (1983) suggested that Pyrenidium has close relationship with Dacampia in Dacampiaceae in its similar ascomatal structures and wall tissues (Crivelli 1983). However, sequence data of three species, Pyrenidium actinellum, P. aff. aggregatum and P. borbonicum, were provided by Huanraluek et al. (2019a). These sequence data formed a distint clade far from Dacampiacceae. Thus, Pyrenidiaceae was resurrected to accommodate species of Pyrenidium.