Taxonomic Study of the Carex tenera Group (Cyperaceae)

According to previous molecular study, the Carex tenera group sensu lato consists of C. tenera s. l. and C. normalis in one clade and C. festucacea, C. oronensis, and C. tincta in a sister clade. We found that Carex tincta, clarified by thorough review of herbarium materials, has a much narrower geographic range than previously thought, centering on Maine (U. S. A.), adjacent states, and adjacent portions of Canada with rare scattered occurrences to western Lake Superior. Carex tenera has traditionally been thought to consist of two varieties: the transcontinental variety tenera and the upper Midwest (U. S. A.) variety echinodes. In light of ecological and chromosomal differences, AFLP genetic distances, and morphological analysis the latter should be recognized as a distinct species, Carex echinodes comb. et stat. nov. Carex echinodes and narrow-leaved forms of C. normalis can be challenging to differentiate morphologically, but widest leaf width, inflorescence internode length, peduncle diameter, and growth habit separate the two taxa. New chromosome numbers are reported, with those of C. tenera (n = 24 + 2III, 26, 27, 28) having a lower range than either those of C. echinodes (n = 37, 38, 39) or C. normalis (n = 34, 35, 36).