A new combination in Nasa (Loasaceae) from Mesoamerica

Abstract

The taxon Nasa triphylla subsp. rudis, previously described as Loasa rhoeadifolia in 1840, has been synonymized since 1900. To maintain nomenclatural stability and preserve the established epithet "rudis," a proposal to conserve the name Loasa rudis has been published. Recent phylogenetic evidence indicates that N. triphylla subsp. rudis is more closely related to N. dyeri than to N. triphylla, supporting the consideration of these three taxa as separate species. Morphological characteristics also differentiate N. triphylla subsp. rudis and N. dyeri from N. triphylla, including stem features, petal appendages, and nectar scale coloration. N. triphylla subsp. rudis is distinguished from N. dyeri by stem characteristics, trichome cover, and pedicel length. Based on the provided evidence, a new combination is proposed for the name Loasa rudis.