A synopsis of the androgynous species of Carex subgenus Vignea (Cyperaceae) in South America

Abstract

This is the first work of a series of thorough studies into the taxonomy and systematics of Carex in South America. Here, we present the systematic placement, biogeographic insights, taxonomic accounts, formal typifications and summarized distributions for the 24 species of Carex subgenus Vignea with androgynous spikes in the continent. We performed a phylogenetic study using the barcode markers ETS, ITS and matK to check the placement of 22 of these species on a previous tree with > 1000 Carex spp. We examined > 600 specimens from 38 herbaria and conducted an exhaustive nomenclatural survey consulting all pertinent literature. South American androgynous species of subgenus Vignea are grouped in seven distinct lineages, corresponding with the same number of inferred colonizations. Most groups seem to have colonized South America during the Plio-Pleistocene, except for species of section Bracteosae, a local radiation that dates back to the Late Miocene. All colonizations by native species seem to have originated from North America. The two putatively introduced taxa are western Palaearctic species. An identification key is provided for the studied species. We make 19 new typifications and a new species (Carex pedicularis) is described.