Leptinella filiformis

A creeping perennial, L. filiformis forms a low mat, spreading indefinitely via thin rhizomes on the soil surface. It has small green or brown feathery leaves, up to 2 cm (0.8 in) long. Its flowers are small (2–3 mm (0.08–0.12 in)) white button-shaped inflorescences on thin stalks.

This species is known only from Marlborough and Canterbury in the northeast South Island. Although initially recorded from the Canterbury Plains, no further specimens were collected there. In 1919, Cockayne wrote: Cotula filiformis until a year or two ago had been seen by no living New Zealand botanist, though it was known that Haast collected it on the Canterbury Plain. Thanks, however, to its rediscovery by Mr C.E. Christensen [in 1912], it has since proved to be fairly common on the Hanmer Plain. L. filiformis had around the same time been found by Cockayne in the Awatere Valley, Marlborough. Subsequent collections were from these two areas: the plain in the Hanmer Valley, Canterbury (and one specimen from Culverden, 40 km (25 mi) away), and the Awatere Valley around Molesworth Station. This species prefers open bare ground with little other vegetation. It grows in grassland and open shrub land on basins, plains, and dry alluvial river terraces up to 600 m (2,000 ft) above sea level. Field observations suggested it grew best in areas of bare ground created by excessive numbers of rabbits; when rabbits were removed, L. filiformis was swamped by returning vegetation.