This species is cited "Ocellularia microstoma (Mull. Arg.) Hale, Mycotaxon 11: 134 (1980)" in Mangold et al. (2009). In Hale (1980), however, Thelotrema microstomum Mull. Arg. Is transferred to Myriotrema [as M. microstomum (Mull. Arg.) Hale]. This makes it necessary to validate the combination O. microstoma in accordance with the present classification of the Graphidaceae (inkl. Thelotremataceae) (e.g., Frisch et al. 2006, Mangold et al. 2009; Rivas Plata et al. 2012).