Family: Iridaceae (Iris family).
Native of South Africa.
Occurrence: A very common and widespread weed in paddocks, roadsides, waste areas and bushland.
The corms are a food source for cockatoos and corellas. Although called Onion Grass, it is neither a grass nor a member of the onion family.
Similar species: Small-flowered Onion Grass (R. minutiflora) is a smaller plant, with smaller and paler flowers, and the petals have blunt tips. It is widespread but less common than Onion Grass.
Both are environmental weeds.