A loosely tufted annual grass, culms to about 1.4 m high, very variable, of wild and cultivar forms; occurring only in limited but disparate localities in Ivory Coast to N Nigeria between 400 to 1000 m altitude with rainfall 900–1000 mm p.a. (1, 10).The grain is edible, but as the grain integuments are not readily detached in threshing, it is awkward to use and is consumed imperfectly cleaned. Nevertheless it is an important supplementary food to people in the Atakora uplands of Togo and Dahomey, and more especially to the Birom tribe of the Jos Plateau in N Nigeria for whom it serves as a staple (4–6, 8, 10). The plant is very variable. It is a cultigen, but of uncertain provenance. FTEA suggests an origin from D. ternata (A Rich.) Stapf (3), a widely dispersed species of eastern and southern Africa and tropical Asia. Alternatively it may be derived from D. barbinodis Henr. (2), a sub-Saharan species with which it is found growing admixed in a wild state in N Nigeria (9). Cultivars of D. iburea have black grain, hence the allusion to blackness in the English and French names. This colour marks them apart from the cultivars of D. exilis (q.v.), or white acha, whose grain is white, grey, brown or red (4). They grow taller, to 1.4 m high, whilst D. exilis cultivars attain 60–90 cm in height only. In N Nigeria they are generally the last of the acha cultivars to be planted (towards the end of June), and then on the more fertile soil, though it is said they do well on poor and exhausted land (5). Harvesting is in November/December. Yield is usually lower than from cultivars harvested earlier due to adverse effect of the harmattan. Plants may sometimes be grown intermixed with millet (7).The grain is eaten as porridge or mixed with the meal of other cereals (6). A common confection in Nigeria and Dahomey is couscous, while in Togo it is fermented to a drink called tchapalo (1). Chemical analysis of the unmilled grain shows good dietetic value with carbohydrates 77.5% and protein 9.9% (1).