Kingdom: Plantae
(Unranked): Angiosperms
(Unranked): Eudicots
(Unranked): Asterids
Order: Asterales
Family: Asteraceae
Tribe: Anthemideae
Genus: Leptinella (was Cotula see text below)
Species: L. pusilla
Scientific name: Leptinella pusilla
Synonyms: Cotula perpusilla, Cotula angustata
Common name: Purple Brass Buttons

Leptinella pusilla is a dioecious, creeping, tufted perennial native herb of coastal to subalpine (0-1200 m) areas but it is more frequent at lower altitudes. Usually found in open sites on gravel, sand or in sparsely vegetated tussock grassland, or in the shade of rock outcrops in areas of the North and South Islands of New Zealand.
It has a tight ground cover habit forming a matt of fine small purple-grey to bronze fern-like leaves. It grows to a height of 0.01m and has a spread of 0.75m. It has rhizomes which are deeply buried.
Miniature button shaped yellow flowers top it in August - November. 
Sold at nurseries.

For over 100 years, Leptinella species were considered part of the genus Cotula, but the genus Leptinella was reinstated by Lloyd & Webb in 1987. They determined that all species of Leptinella are distinguished from those of the other two sections of Cotula, and other anthemideae, by the conspicuous "inflated" corollas of the female florets and by chromosome numbers based on x = 26 where known.

For more detailed information: http://nzpcn.org.nz/flora_details.asp? ID=917

Leptinella pusilla-001.JPG

Leptinella pusilla-002.JPG

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/