Revision of the <Emphasis Type="Italic">Rhynchospora glomerata</Emphasis> species complex,focusing on the taxonomic status of <Emphasis Type="Italic">R. leptocarpa</Emphasis> (Cyperaceae)

Rhynchospora glomerata and its closest relatives comprise a group of beakesedges widespread and frequent in much of North America. The classification of the R. glomerata complex remains unresolved and controversial. The goals of this study are to determine the number of taxa in the complex and their ranks, and identify their best diagnostic characters. Measurements of eight characters from each of 101 specimens from throughout the geographic range of the complex furnished data for morphometric analyses. These analyses reveal the R. glomerata complex contains three species and no infraspecific taxa: R. capitellata, R. glomerata, and R. leptocarpa. We detected 10 validly published basionyms in the complex, five of which required lectotypification. Accordingly, we designated lectotypes for R. glomerata var. discutiens, R. glomerata var. minor, R. glomerata var. paniculata, and R. glomerata var. robustior, and the second-step lectotype for R. capitellata var. controversa.