Taxonomic survey of the Araceae Juss. in the coastal region of Piauí state, northeast Brazil, including the Rio Parnaíba Delta

This is the fi rst taxonomic study of the family Araceae in the state of Piaui, Northeast Brazil. The survey was conducted in four coastal municipalities (Ilha Grande, Luiz Correia, Cajueiro da Praia and Parnaiba) of the state. Eight species were recorded in six genera: Lemna aequinoctialis Welw., L. valdiviana Phil., Montrichardia linifera (Arruda) Schott, Pistia stratiotes L ., Wolffiella lingulata (Hegelm.) Hegelm., W. oblonga (Phil.) Hegelm., Taccarum ulei Engl. & K. Krause and Spathicarpa gardneri Schott. Of these, two are geophytes (T. ulei, S. gardneri ) and the others are aquatic macrophytes. Descriptions, illustrations, phenology and habitat information are given for each species as well as a key to their identifi cation.