Carex yankouensis, a new species of Cyperaceae from limestone landform in northern Guangdong, China

<i>Carexyankouensis</i>, a new species of Cyperaceae (CarexsectionRhomboidales) from the limestone landform in northern Guangdong, China is described and illustrated. The new species is similar to <i>C.brevicuspis</i> C. B. Clarke, but differs in having shorter culms (10-15 cm vs 20-55 cm) and spikes (1-1.5 cm vs 3.7-7 cm), leaves wider (15-20-35 mm vs 5-10 mm) and lighter colored (pale green or yellow-green vs dark green), nutlet beak oblique (vs erect or slightly curved), and slightly thickened (vs thickened) style base. Following the IUCN Red List Criteria (IUCN 2024), <i>Carexyankouensis</i> is assessed as 'Data Deficient (DD)'.