A SYNOPSIS OF ALISMATACEAE FROM THE SEMI-ARID REGION OF NORTHEASTERN BRAZIL

The Alismataceae (excluded Limnocharitaceae) comprises twelve genera of herbaceous aquatic plants. Only two of its genera (Echinodorus and Sagittaria) are native to the Neotropics. A survey of the species of Alismataceae confirmed the occurrence of four taxa of Sagittaria and eleven of Echinodorus from the semi-arid region of northeastern Brazil. Analytical keys to differentiate the genera and species are provided, as well as illustrations of their taxonomic characteristics and data on their geographical distribution. Echinodorus macrocarpus to be considered synonymous with E. pubescens. Echinodorus reticulatus is considered as a different species from E. longipetalus. There are five excluded taxa from the Brazilian semi-arid region: E. grandiflorus, E. macrophyllus, E. martii, E. bolivianus, and E. decumbens.