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 Stirtonia A.L.Sm. (1926), nom. cons.