Abstract
Carex qingyuanensis, a new species of Cyperaceae from Guangdong Province, China, is described and illustrated. The new species is morphologically similar to Carex peliosanthifolia F. T. Wang & Tang ex P. C. Li, but it can be distinguished by the racemose inflorescence branches appearing single (rarely binate or ternate) (vs. binate or ternate), one (rarely two or three) (vs. 1–3) spiked, male part of linear-cylindrical spikes much longer than the female part (vs. just male part short-cylindrical and slightly longer than female part), style base thickened (vs. not thickened) and perigynium horizontally patent with a short (vs. long and excurved) beak. Phylogenetic analysis, based on the two nuclear DNA regions (ETS 1f and ITS) and three chloroplast DNA regions (matK, ndhF and rps16), suggests that the new species belongs to sect. Siderostictaes.s. of subg. Siderosticta and shows a closer phylogenetic relationship to Carex scaposa C. B. Clarke.