A phylogenetic analysis of Alismataceae was conducted using data from the internal transcribed spacers (ITS-1;2) of the nuclear ribosomal genes, the chloroplast gene rbcL, the flanking introns and coding region of the chloroplast matK gene and morphology. The aquatic, monocotyledonous Alismataceae consists of 13 genera which are similar in habitat, pollination and morphology. Numerous convergences and reduced vegetative and reproductive structures make it difficult to interpret morphological characters for phylogenetic analysis. Our combined data set showed high congruency with results published previously using rbcL data alone. The combined molecular data consistently show a monophyletic origin for the family. Other results include a sister group relationship of Limnocharitaceae and Alismataceae, a polyphyletic origin for the genus Echinodorus and several well-supported monophyletic clades within the family.

Key words: Alismataceae, ITS, matk, morphology, phylogeny, rbcL, systematics