Kingdom:Plantae
(Unranked): Angiosperms
(Unranked):Eudicots
(Unranked): Asterids
Order:Asterales
Family:Asteraceae
Tribe: Anthemideae
Genus: Leptinella (was Cotula see text below)
Species: L. squalida 'Platts Black'
Scientific name:Leptinella squalida 'Platts Black'
Synonyms: Creeping Cotula, Cotula Platts Black, Black Brass Buttons, Cotula squalida. Cotula leptinella 
Common name: Leptinella squalida 'Platts Black'

Leptinella squalida 'Plats Black' is a vigorous hardy creeping evergreen NZ native groundcover with fine, feathery, dark/black or bronze-green to green coloured foliage (2.5 to 5cm long. It needs full sun to maintain the foliage colour. It grows to a height of 10cm and a width of 1m. It has insignificant green flowers during the summer (6mm across). Propagation is by dividing it into smaller pieces.
It is a cultivar of Leptinella squalida an alpine native found in damp rock places and along stream margins from Bay of Plenty to Stewart Island up to elevations of 1300m.
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.

Leptinella squalida Platts Black .JPG Leptinella squalida Platts Black -007.JPG

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