Nymphaea is the most diverse genus (45 species) of the order Nymphaeales, which is congruently inferred as the second branch of the angiosperm tree. In a collaborative effort, several genomic regions approximately 5000 bp of the genomic regions trnT-F , trnK-intron including matK , and ITS1-5.8S-ITS2 were sequenced from nearly all species. In contrast to previous classifications a BAN-clade is hypothesized within Nymphaea, comprising the subgenera Brachyceras (pantropical) and Anecphya (australasian) and forming a terminal lineage sister to the temperate subgen. Nymphaea. A second major lineage includes an assemblage of the SE-African N. petersiana with the subgenera Lotos and Hydrocallis. Based on a synopsis of the fossil record the earliest known appearance of Nymphaea is Middle Eocene (45 MYBP). Combining palaeobotanical and molecular evidence it seems that a rapid early differentiation into major clades is contrasted by comparatively recent species diversifications within these clades. Possible patterns of spatial differentiation are discussed. In the case of the temperate subgen. Nymphaea-clade which comprises closely related circumboreal taxa (pygmy waterlilies) as well as species confined to either North America or Europe, possible patterns of spatial differentiation are discussed.

Key words: basal angiosperms, molecular systematics, Nymphaea, paleobotany, phylogeny