The Apodi-Mossoró River, located in the Caatinga biome, has its course characterized by diverse landscape sand humid environments, as well as by many members of the family Cyperaceae. Studies on the flora of Cyperaceae are scarce in northeastern Brazil and nonexistent for Rio Grande do Norte State. Twenty-one botanical expeditions were undertaken in this area during the period from July 2007 to May 2008 on four main points in the municipalities of Felipe Guerra, Governador Dix-Sept Rosado, Luís Gomes, and Mossoró. Seven genera and twenty-five species of Cyperaceae were found in the Apodi-Mossoró River, twenty-one of which are new records for Rio Grande do Norte State.This figure more than doubled the number of species of the family known to occur in this Brazilian State. Botanical descriptions, taxonomic comments, identification keys, and illustrations are provided.
macrophytes; monocots; riparian vegetation; sedges
