Phylum Ascomycota Caval.-Sm. (1998) - sac fungi Subphylum Pezizomycotina O.E. Erikss. & Winka (1997) Class Arthoniomycetes O.E. Erikss. & Winka (1997) Order Arthoniales Henssen ex D.Hawksw. & O.E. Erikss. (1986) Family Arthoniaceae Rchb. (1841) Genus Arthothelium A.Massal. (1852)