We present the new combination Pleopeltis minima (Bory) J. Prado & R. Y. Hirai and we selected a lectotype for Marginaria minima described by Bory, based on material from southern Brazil. This taxon has a wide range in the southern part of South America and it has been recognized in the rank of species and/or variety by several previous authors, but its correct name has been misleading. Recently it has been treated as a member of Pleopeltis, but with a wrong epithet. The nomenclatural mistake involving this species arose because there are different interpretations of some nomenclatural rules defined in the IBCN. A similar misunderstanding of the same rule is also discussed for a species in Lindsaea.