Nymphaea is the largest genus (approx. 45 species) of the family Nymphaeaceae, occupying a position near the base of the angiosperm tree. Five Nymphaea subgenera are recognized, each showing a particular geographic distribution: Brachyceras (pantropical), Anecphya (australasian), Lotus (paleotropical), Hydrocallis (neotropical), and Nymphaea (north temperate). A complex spectrum of morphological, anatomical, and palynological characters and a comparatively rich fossil record made Nymphaea destined for an interdisciplinary approach integrating molecular biology, morphology, and paleobotany to gain a better understanding of the phylogeny of the genus and its distribution and diversification over the continents. We sequenced the trnT-trnF region of the chloroplast genome of 15 representative species of Nymphaea. Sequence divergence is highest in the intergenic spacer between the trnL (UAA) 3' exon and the trnF (GAA) gene. Insertion/deletion mutations ranging from 1 to 17 bp account for a length variation of the spacer from 375 to 407 bp within the genus Nymphaea. Species of subgenera Hydrocallis and Lotus share length mutations of 5 and 16 bp, and a series of 8-9 As instead of 7 Ts. Parsimony analysis places species of subgen. Hydrocallis in a basal position together with subgen. Lotus. The pantropical subgen. Brachyceras is most likely paraphyletic and the australasian subgen. Anecphya nests within it. The north temperate taxa of subgen Nymphaea form a well resolved terminal clade. Molecular data suggest that the syncarpous northern temperate species of subgen. Nymphaea are more closely related to the apocarpious subgenera Brachyceras and Anecphya than is reflected by the classical concept of an apocarpous lineage (uniting subgen. Brachyceras and Anecphya) that is sister to an syncarpous lineage (uniting subgen. Lotus, Hydrocallis, and Nymphaea).

Key words: Nymphaea , trnT-trnF , molecular systematics, phylogeny