Arthoniaceae

The Arthoniaceae are a family of lichenized, lichenicolous and saprobic fungi in the order Arthoniales. The Arthoniaceae is the largest family of Arthoniales, with around 800 species. Most species in Arthoniaceae belong in Arthonia which is the largest genus with 500 species. The second and third largest genus is Arthothelium with 80 species, and Cryptothecia with 60 species.

Arthonia is the type genus of Arthoniaceae, and it is known to be a polyphyletic and paraphyletic genus. The process of splitting Arthonia into monophyletic groups is an ongoing process. In order to make Arthonia monophyletic, several genera have been described or resurrected.