caesalpinia hintonii

Leptinella squalida is a species of flowering plant in the daisy family, native to New Zealand. Known as 'brass buttons' for its yellow button-like flowers, it grows to about 5 cm (2 in) tall, spreading indefinitely via rhizomes.A cultivar with almost black foliage, L. squalida 'Platt's Black', is grown as an ornamental plant, particularly in rock gardens and in flowering lawns.