Rhynchospora sect. Luzuliformis is one of the 28 sections of the genus proposed by Kükenthal, the last taxonomist to have studied the section. It has three species and two varieties, and most species are found in open areas of the southern grasslands of South America. Species were studied in the field and in herbaria, and literature was reviewed. As main results we highlight the new specific status and new name, Rhynchospora boeckeleriana, the designation of two neotypes and three lectotypes, and a new record for Brazil, R. praecincta. Full descriptions of the four species are provided, as well as a key to distinguish the species of section Luzuliformes.