Iris chrysographes, commonly known as the Black Iris, is a plant species that belongs to the genus Iris. It is native to S China and Myanmar (Burma), growing in meadows, stream sides, hillsides and forest margins. Other irises known as the Black Iris include Iris nigricans which is the national flower of Jordan, Iris petrana which also grows in Jordan, and Iris susiana.
Horticultural classification: Sino-Siberian Iris, Beardless Iris. Herbaceous perennial with creeping rhizomes. Leaves linear and grayish green, to 70 cm long. Flowering stems 25–50 cm, hollow. Flowers reddish violet to very dark violet, almost velvety black, 6–9 cm in diameter, outer tepals usually with golden yellow stripes. Deliciously fragrant flowers are in June to July.
Iris chrysographes is easily cultivated and requires a fertile soil which does not dry out during the growth period. Grow in full sun. Hardy to USDA zone 4. Propagation by seeds or division in the spring. Cultivars must be divided. For cooler areas plants do best if planted in the spring.
Some cultivars are grown, mainly "black" flowered clones under names as 'Black Beauty', 'Black Knight', 'Black' (syn. 'Black Form', an invalid name), 'Ellenbank Nightshade', 'Stjerneskud' and 'Kew Black'. 'Rubella' is purplish violet. Iris chrysographes has been used in a number of hybrids with other species.
Source, Images: http://en.wikipedia.org/wiki/Black_Iris