Hairy Burr-daisy

Calotis hispidula is an annual ascending herb which may grow to 10 to 12 centimetres (3.9 to 4.7 in) high, with rough, hirsute hairs. It has no basal leaves; the aerial leaves are somewhat wedge-shaped, 0.5 to 2 centimetres (0.20 to 0.79 in) long and 1 to 7 millimetres (0.039 to 0.276 in) wide. The barbed flower heads range from 4 to 10 millimetres (0.16 to 0.39 in) in diameter, supported by bracts that encase a conical, scaled receptacle. The florets are yellow and sprout to be 1 mm long.

Calotis hispidula grows in heavy clays to shallow stony soils, in a wide variety of communities; it is widespread, especially in inland districts. Known and current populations range within New South Wales, Queensland, Victoria, Northern Territory, South Australia, and Western Australia. It is found abundantly in Central Australia.

The species grows in sandy soil on flats, low dunes and small hills and appears to be associated with Acacia woodlands and shrublands dominated by chenopods. Apparently a perennial that flowers in the first year of growth; no plants of this species have been observed to survive for more than two years; flowering is recorded for September and fruit have been collected in October, though it will flower as early as August.

Case study. At Mount Mulyah, northwest of Louth, New South Wales, Calotis spp. grows in an area cleared of original acacia cambagei woodland and subsequently invaded by dodonaea viscosa subsp. angustissima, which repressed the growth of herbaceous species. No regeneration of this species has been seen at Mount Mulyah since 1984. Calotis hispidula can often be found growing in conjunction with other Calotis species, such as C. cymbacantha and C. erinacea, and are very similar morphologically.