Two new combinations in Oxossia (Passifloraceae s.l., Turneroideae)

Recently, a new genus segregated from Turnera L. (Passifloraceae s.l., Turneroideae) was described to accommodate a group of species that are phylogenetically well-supported. This new genus, Oxossia L.Rocha, was established to reflect these evolutionary distinctions within the subfamily Turneroideae. Although Oxossia does not present clear autapomorphies, it appears to be morphologically cohesive and can be recognized by a combination of characters that support its recognition as a separate evolutionary lineage. These diagnostic features include conspicuous stipules, flowers arranged in congested inflorescences, typically white corollas, pilose styles and stamens, and stamens that are basi-dorsiventrally adnate to the floral tube. Concomitantly with the establishment of Oxossia, we describe two species from northeastern Brazil, Turnera acangatinga Costa-Lima & E.C.O.Chagas and T. ibateguara Costa-Lima & E.C.O.Chagas, which exhibit morphological traits consistent with the circumscription of this new genus. Both species present unique reproductive characters that align them with the diagnostic features of Oxossia, including distinctive floral structures that set them apart from typical Turnera species. To update the taxonomy of this group and reflect the currently accepted circumscription, we followed the criteria of the International Code of Nomenclature for algae, fungi, and plants, and formally propose the transfer of these species to Oxossia. This results in the new combinations Oxossia acangatinga (Costa-Lima & E.C.O.Chagas) Costa-Lima & E.C.O.Chagas comb. nov. and O. ibateguara (Costa-Lima & E.C.O.Chagas) Costa-Lima & E.C.O.Chagas comb. nov.