Based on recent findings of phylogenetic studies using character sets from all three genomic compartments and from morphology, Ondinea purpurea is transferred to Nymphaea and the new name N. ondinea is validly published. This change in classification implements the criterion that higher taxa should be monophyletic. Although, compared to other species of Nymphaea, the Australian N. ondinea appears to be phenotypically very different, most shifts in character states that led to its evolution (e.g., loss of perianth in some of the populations, decrease in stamen and carpel number) are rather quantitative. Several characters not only support a position of Ondinea within Nymphaea (such as an eusyncarpous gynoeceum with carpels less than 50 % fused), but also allow its unambiguous identification as a species of Nymphaea.