A taxonomic and phytogeographic treatment of the Rhynchospora (Cyperaceae) of South Carolina and the eastern United States, including a revision of Rhynchospora section Globulares.

摘要

The coastal plain of the southeastern United States is a center of diversity for Rhynchospora. Despite this fact, the taxonomy, ecology and distribution of the genus remains poorly documented. Through the morphological examination of over 2600 specimens and collection of over 1000 additional specimens, a taxonomic revision was completed for the species of Rhynchospora occurring in South Carolina and the eastern United States. The revision was based upon morphological, phytogeographic and ecological data. Taxonomic delineations were based upon typological and ecological species concepts. The data were analyzed using statistics, ordination and cluster analysis to describe morphological and ecological limits within species. Original descriptions, a dichotomous key to species, habitat and range descriptions were constructed for each species. Original illustrations were prepared for every species occurring in South Carolina. The ranges of the species occurring in South Carolina were compiled providing the first accurate interpretation of their distribution. Type specimens were examined and designated for all species, including the designation of 5 neotypes and 4 lectotypes. This treatment documents 72 species in the eastern U.S. and 58 for South Carolina. During the course of this study, nine species were reported new for South Carolina, four species were removed from the flora of South Carolina and one species, Rhynchospora leblondii was reported new to science. The taxonomic revision also produced the resurrection of 9 taxa previously not considered distinct.; Within section Globulares two groups of species with complicated taxonomic histories were examined in detail to resolve problematic nomenclature. The four taxa comprising the R. globularis species group represent four morphologically and ecologically distinct taxa. Phenology partially separates one of the species, R. pinetorum, from its close relatives. The species group consists of one edaphic endemic, one granite outcrop endemic, a species adapted for exploiting early successional habitats on disturbed soils, and a closely related species growing in mature, dense, grasslands.