Towards a new classification of Salvia s.l.: (re)establishing the genus Pleudia Raf

Salvia L. in its traditional circumscription is the largest genus within the mint family. To date, the magnitude of the task has rendered it difficult to provide a genus-wide revision based on morphological data. Current molecular investigations based on a dense taxon sampling representing the whole phenotypic diversity and distribution range of Salvia confirmed that the genus is polyphyletic. Salvia species fall in 4 distinct clades, although all of them, except Clade IV, also include non-Salvia genera. A taxonomic revision is thus urgently needed with two different approaches that have to be considered: (1) to include the 5 morphologically distinct non-Salvia genera in Salvia or (2) to split Salvia s.l. into Salvia s.s. and several additional genera. Since Salvia is already highly heterogeneous in species distribution, morphology, and chromosome number, we prefer to split the genus into molecularly well-supported clades. This new concept may facilitate monographic studies and more focused analyses of character evolution within or between the clades. Species representing Salvia sect. Eremosphace Bunge (subclade III-A) were chosen exemplarily to provide arguments for elevating this particular group to the level of genus (Pleudia Raf.).