Ornduffia calthifolia is a species of plant in the Menyanthaceae family of wetland plants that is endemic to Western Australia.
The species is a marsh inhabitant; it grows as an erect, aquatic or semiaquatic, perennial herb to a height of 0.4–1.2& m. The white flowers appear from September to December.[1]
The species occurs in the Avon Wheatbelt, Jarrah Forest, Swan Coastal Plain and Warren IBRA bioregions of Southwest Australia.[2] It is found in wetlands such as freshwater lakes and swamps.[1]