Xanthosoma riparium (Araceae), a new species from Goias, Brazil

A new species of a caulescent Xanthosoma (X. riparium) from Serra Dourada, state of Goias, Brazil, is described and illustrated. Xanthosoma riparium is most similar to X. mafaffoides G. S. Bunting, X. undipes (Jacquin) Schott, and X. maximilianii Schott, but differs from all these species in having fewer primary lateral veins that arise at a more acute angle. Moreover, the primary lateral veins in X. riparium are close to each other near the sinus, becoming more scattered toward the apex, not regularly scattered along the midrib like in X. mafaffoides, X. maximilianii, and X. undipes. This new species appears to be the only caulescent Xanthosoma known to be native to central Brazil.