Abstract
A taxonomic survey based on revision of herbarium material and critical study of bibliography is conducted to elucidate the taxonomic and nomenclatural status of four problematic Carex names: C. eremitica, C. mediterranea, C. orbicularis subsp. kotschyana var. caucasica, and C. transcaucasica, all described from SW Asia. We find that C. eremitica should be considered a synonym of C. stenophylla (section Boernerae). We perform the lectotypification of C. mediterranea, a synonym of C. hispida (section Thuringiacae). We discuss the taxonomic affinities of C. transcaucasica (section Phacocystis) and combine this name under C. nigra (C. nigra subsp. transcaucasica). We synonymize C. orbicularis subsp. kotschyana var. caucasica to C. nigra subsp. transcaucasica. Eventually, we indicate that populations previously believed to be C. orbicularis actually belong to C. nigra subsp. transcaucasica, confirming its presence in Iran, and expanding its range to Iraq.