Ondinea is a monotypic genus of flowering aquatic plants in the family Nymphaeaceae native to northwestern Australia. It grows from a corm-like rhizome and is found in ephemeral pools and rivers that are dry for a significant portion of the year. The rhizome survives the dry season in drying mud.
Ondinea purpurea, the only species in the genus, is a small plant that grows, among other places, in shallow creeks of the Kimberley region of Western Australia. It grows from a rhizome that is about 2.5 cm long, and has leaves that are approx 25 cm long, mostly submerged but with the occasional small floating leaf.