Melaspilea demissa (Tuck.) Zahlbr. (lichenized Ascomycota) in eastern North America with a key to North American species of Melaspilea s. lat.

Recently collected specimens of the crustose lichen Melaspilea demissa from south-eastern USA have been compared with those of Melaspilea spp. previously determined from North America. A review of both the historical and contemporary treatments of this species is provided. A lectotype was selected from the type collection of M. demissa in FH and is here proposed as it best matches incomplete citations in the original treatment. We also discuss the nomenclatural and taxonomic status of the name Opegrapha cymbiformis var. deformis (considered a synonym of M. gibberulosa). North American specimens of M. gibberulosa were found to be misidentifications, as were specimens attributed to M. lentiginosula, M. mesophlebia and M. octomera. We therefore recommend that these species be removed from the North American lichen checklist. We also present a key to North American Melaspilea. [ABSTRACT FROM AUTHOR]