Lobelia rhombifolia, commonly known as tufted lobelia, is an annual plant from southern Australia. They range from 5 to 30 cm in height and produce purple flowers, with a white throat and two recurved upper lobes. The flowers appear at different times across their native range:
The species was first formally described in 1845 by German botanist Johann Lehmann in Plantae Preissianae.
In Tasmania, the species is classified as "rare" under the Threatened Species Protection Act.