Marcelaria is a genus of crustose lichens in the family Trypetheliaceae. It has three species. The genus was circumscribed in 2013 by André Aptroot, Matthew P. Nelsen, and Sittiporn Parnmen, with Marcelaria purpurina assigned as the type species. The genus contains species that were previously in the Laurera purpurina species complex. Species in Marcelaria contain secondary compounds such as red, orange, and yellow anthraquinones, and sometimes lichexanthone. The genus name honours Brazilian lichenologist Marcela Cáceres.
In 2016, Aptroot and Nepi made a formal proposal to conserve the name Marcelaria over Buscalionia. This decision was necessitated by the rediscovery of type material originally described in 1940 by Maria Cengia Sambo as Buscalionia rubra, which technically should take priority as per the rules of botanical nomenclature. Given the widespread recognition and use of the name Marcelaria, especially for the type species M. purpurina, the authors advocated for its conservation to maintain clarity and consistency in lichenological studies.