Abrothallus De Not. Giorn. Bot. Ital. 1: 194 (1846).
= Vouauxiomyces Dyko & D. Hawksw., Lichenologist 11(1): 57 (1979).
MycoBank number: MB 4; Index Fungorum number: IF 4; Facesoffungi number: FoF 08048; 42 morphological species (Species Fungorum 2020), 20 species with molecular data.
Type species: Abrothallus bertianus De Not. Giorn. Bot.Ital. 1: 194 (1846).
Notes: De Notaris described Abrothallus as a lichenized taxon (De Notaris 1846, 1849). Tulasne (1852) and Lindsay (1857) unequivocally established its lichenicolous habit. Suija et al. (2018) fixed the nomenclatural problems concerning the exact date of publication, confirming A. bertianus as the type species. They also reviewed the material described by Giuseppe De Notaris, Søren Christian Sommerfelt, and Ignaz Kotte lectotypifying Abrothallus species described by these authors (Suija et al. 2018). These authors also introduced the combination A. santessonii (≡ Vouauxiomyces santessonii), providing an updated description for this taxon. Pérez-Ortega et al. (2011) established the connection between the sexual and asexual morphs. The number of species is tentative since there are numerous single collections occurring on unusual hosts that may represent new species and there are only a few collections from certain regions, e.g. from Africa and Asia. Recent studies focused on the taxonomy of species growing on Peltigerales (Suija et al. 2011, 2015). However, species delimitation, especially those on specimens growing on Parmeliaceae, is difficult and in need of a thorough revision (Suija et al. 2018). For morphology of the type species, see Suija et al. (2018) (Fig. 2).
Fig. 2 Morphological and anatomical features of Abrothallaceae. a Habitus Abrothallus welwitschii, mature apothecia. b Habitus A. welwitschii, young apothecia with greenish pruina. c Cross-section of A. parmotrematis on Parmotrema sp. d Interascal elements from A. bertianus. e One-septate ascospore of A. welwitschii, with surface showing ornamentation. f Ascus of A. boomii. g Three-septate ascospores of A. suecicus. h Scanning electron micrograph of A. welwitschii ascospores. i Ascospore of A. buellianus showing occasional splitting at the septum. j A. caerulescens asexual stage (pycnidium, Vouauxiomyces-type). k Conidia from A. boomii. l Lichenoconium sp. on A. santessonii ascoma. Scale bars: a–b = 0.5 mm, c = 50 µm, d–h, k = 10 µm; i = 5 µm, j = 30 µm, l = 20 µm