Phylum Ascomycota Caval.-Sm. (1998) - sac fungi Subphylum Pezizomycotina O.E. Erikss. & Winka (1997) Class Xylonomycetes Gazis & P. Chaverri (2012) [monotypic] Order Xylonomycetales Gazis & P. Chaverri (2012), orth. inval. [monotypic] Family Xylonomycetaceae Gazis & P. Chaverri (2012), orth. inval. Genus Symbiotaphrina Kühlw. & Jurzitza ex W. Gams & Arx (1980)