A taxonomic revision of Schoenus cuspidatus and allies (Cyperaceae, tribe Schoeneae)—Part 2

Abstract

This is the second half of a two-part taxonomic revision on the morphologically complex Schoenus cuspidatus and allies group. This revision is a continuation of recent taxonomic work that has transferred 24 southern African species from Tetraria and Epischoenus into Schoenus, revised the taxonomy of the Schoenus compar—Schoenus pictus and allies group, as well as part of the S. cuspidatus group. Most recently, we presented descriptions of three new species and a new combination among the Southern African Schoenus species. Here, we revise the delimitations and distributions of five species (Schoenus compactus, Schoenus crassus, S. cuspidatus, Schoenus galpinii and Schoenus riparius) based on data from a review of specimens from twelve herbaria and recent field collections. We also describe three new species to science: Schoenus australis, Schoenus brunnescens and Schoenus graciliculmis—the first two of which are endemic to the Western Cape Province of South Africa, while S. graciliculmis is endemic to the Eastern Cape Province. We present a taxonomic key, an updated nomenclature and provide revised descriptions and distribution maps for these nine Schoenus species. Finally, we discuss unresolved taxonomic issues within this group, especially within the broadly circumscribed S. cuspidatus, and outline circumscriptions and specimens that require further study. Species within this group are perennial, caespitose graminoids with terete, leafless culms, and although most of these species have broad elliptic nutlets, there are differences in growth and spikelet forms that differentiate species.