Trithuria bibracteata is a species of aquatic plant in the family Hydatellaceae endemic to Western Australia.

[4] The dehiscent fruit[3] bears 0.4-0.6 mm long,[4] desiccation-tolerant,[7] black to brown,[8] ellipsoid to ovoid seeds,[3] which require light to germinate.

[1][4] The type specimen was collected by R. D. Royce in Boyanup, Western Australia in l947.

[2] It occurs in clay and mud along stream edges,[2] ephemeral pools,[16] and swamps.

[8][9] It inhabits winter-wet habitats,[2][9] which dry in the Australian summer from December to February.