The floral biology of Ondinea purpurea, consisting of an apetalous subspecies and a newly discovered petaloid subspecies, has been investigated. Anthesis occurs over a 3-day period. First-day flowers are protogynous and characterized by colourful reflexed perianth and stamina1 parts. The pollen-receptive stigmas of first-day flowers secrete a fluid that fills the small stigmatic cup. As potential pollinators are attracted and attempt to land on the distally exposed gynoecium, they contact the stigmatic fluid which loosens pollen from the insect’s body and pollination is achieved. Second- and third-day flowers are functionally staminate. On the basis of comparative reproductive anatomy and pollination syndromes the placement of Ondinea in the Nymphaeaceae s. str. is supported.