Aquatic macrophytes from northeastern Maranhão: floristic survey and identification key

Abstract

This survey aimed to collect and identify the aquatic macrophyte species present in the Gira Mundo lagoon and Passagem do Canto stream, Barreirinhas, state of Maranhão, Brazil, from November 11, 2014 to December 10, 2015. For taxa identification, representative specimens of each species were collected and pressed. After identification, these was deposited in the Herbarium Rosa Mochel, at the State University of Maranhão, in São Luís. Eleven species were identified, distributed in ten families in the Gira Mundo lagoon, the most representative being the Onagraceae family with two species. A univegetal cover of was observed Salvinia auriculata in the lagoon, where this phenomenon could be related tp the predominantly lentic characteristic of the lagoon, as well as the anthropization observed in loco. In the Passagem do Canto stream, eight species were identified in seven families. Cyperaceae with two species was the most representative. Most of the species found were 100% frequent. Nymphaea lingulata, Aeschynomene sensitive, and Cabomba aquatica occurred at both collecting points. The most significant biologic forms in the Gira Mundo lagoon were amphibious and emergent, differing from the lotic region in the Passagem do Canto stream, where fixed submerged forms were the most representative.