Taxonomic realignment in the southern African Tetraria (Cyperaceae, tribe Schoeneae; Schoenus clade)

Tetraria - an austral genus with 54 currently accepted species - is polyphyletic, with species located across at least three different clades of the Schoeneae tribe of Cyperaceae. The small African endemic genus Epischoenus is embedded within one of these clades-the Schoenus clade of Tetraria. The majority of species in two of the major clades of Tetraria (the Tricostularia and Schoenus clades) are endemic to the Cape Floristic Region of southern Africa. Species in the Tricostularia clade have noded culms and reticulate sheath bases, whereas species of the Schoenus clade do not have nodes along their culms or reticulate sheaths. Importantly, the type species of the genera Schoenus, Tetraria and Epischoenus are resolved as part of the Schoenus clade, and the former has taxonomic priority. Here, we realign the taxonomy of the Schoenus clade of Tetraria to reflect our current understanding of the phylogenetic relationships within the Schoeneae. In addition, we outline the characteristics of three subclades (Tetraria compar-Tetraria picta and allies, Epischoenus and allies as well as Tetraria cuspidata and allies) that will be used to guide species groupings in forthcoming taxonomic revisions. Finally, we transfer 17 species of Tetraria and seven species of Epischoenus to Schoenus.