Circinaria arida sp. nova is described from the Sonoran area. In the Sonoran Desert Lichen Flora 3 it was tentatively treated as Aspicilia desertorum. This name, however, is based on Lecanora desertorum, an illegitimate name introduced by Krempelhuber for both vagrant and saxicolous taxa, but usually only applied to nonvagrant, saxicolous specimens. In the analysis presented here these are shown to represent more than one taxon. For American specimens the epithet elmorei is available, and the combination Circinaria elmorei is proposed.