A floristic inventory of the species of Eleocharis (Cyperaceae) from Rio de Janeiro State - Brazil was made. This research included material from most important Herbaria of Rio de Janeiro (FCAB, GUA, HB, HUNI, R, RB, RBR, RFA, RUSU) as well as plants collected during expeditions to aquatic ecosystems of Rio de Janeiro, between November 1998 and September 2003. The genus Eleocharis is represented in the area by 19 species: Eleocharis acutangula (Roxb.) Schult., E. debilis Kunth, E. elongata Chapm., E. equisetoides (Elliott) Torr., E. filiculmis Kunth, E. flavescens (Poir.) Urb., E. geniculata (L.) Roem. & Schult., E. interstincta (Vahl) Roem. & Schult., E. maculosa (Vahl) Roem. & Schult., E. minarum Boeck.*, E. minima Kunth, E. montana (Kunth) Roem. & Schult., E. mutata (L.) Roem. & Schult., E. nana Kunth, E. pachystyla (C. Wright) C. B. Clarke*, E. radicans (Poir.) Kunth*, E. sellowiana Kunth, E. squamigera Svenson, and E. subarticulata (Nees) Boeck. (*species rare in Rio de Janeiro state). A key of identification, descriptions of species, illustrations, and notes on ecological features and geographical distribution are presented.
Eleocharis; Cyperaceae; Rio de Janeiro
