Myrmaecium Nitschke ex Fuckel, Jb. nassau. Ver. Naturk. 23–24: 227 (1870) [1869–70].
MycoBank number: MB 3385; Index Fungorum number: IF 3385; Facesoffungi number: FoF 06560; – 7 morphological species (Species Fungorum 2020), 3 species with molecular data.
Type species: Myrmaecium rubricosum (Fr.) Fuckel, Jb. nassau. Ver. Naturk. 23–24: 227 (1870) [1869–70].
≡ Sphaeria rubricosa Fr., Elench. fung. (Greifswald) 2: 63 (1828).
Notes: Previously Myrmaecium was treated as a synonym of Valsaria (Ju et al. 1996, Jaklitsch et al. 2015). However, a multi-gene molecular study established the monophyly of Myrmaecium species, and their inclusion in Valsariaceae (Jaklitsch et al. 2015). Myrmaecium can be distinguished from other genera in Valsariaceae by the eu- or pseudostromata, showing ionomidotic reaction (KOH-extractable pigments). Myrmaecium has a worldwide distribution occurring on sun-exposed, corticated logs and branches of coniferous and broadleaf trees. In addition, Myrmaecium fulvopruinatum and M. rubrum are sources of secondary metabolites (Aptroot 1995; Jaklitsch et al. 2015).