<i>Eleocharis</i> R. Br. (Cyperaceae) in the Coastal Region of Piauí State, Brazil: A Floristic Treatment

A taxonomic survey of the genus Eleocharis R. Br. was carried out in the four municipalities of coastal Piauí state (Cajueiro da Praia, Ilha Grande, Luís Correia and Parnaíba) included in the Parnaíba Delta Environmental Protection Area. The survey was based on the morphological study of newly collected and existing herbarium material. Six species, native but not endemic to Brazil, were recorded: Eleocharis elegans (Kunth) Roem. &amp; Schult., E. filiculmis Kunth, E. flavescens (Poir.) Urb., E. geniculata (L.) Roem. &amp; Schult., E. mutata (L.) Roem. &amp; Schult. and E. subarticulata (Nees) Boeckeler. Eleocharis flavescens and E. subarticulata are new records for Piauí and E. subarticulata also for the Brazilian Northeast. Descriptions, illustrations, identification keys and information on geographic distribution and habitat are presented. The identification key is provided in English and Portuguese.