Phylum Ascomycota Caval.-Sm. (1998) - sac fungi
   Subphylum Pezizomycotina O.E. Erikss. & Winka (1997)
     Class Lecanoromycetes O.E. Erikss. & Winka (1997)
       Subclass Ostropomycetidae V. Reeb, Lutzoni & Cl.Roux (2004)
         Order Ostropales Nannf. (1932)
           Family Odontotremataceae D.Hawksw. & Sherwood (1982)
             Genus Xerotrema Sherwood & Coppins (1980)