Shrub, up to 12 ft. high, very glaucous. Leaflets 9, opposite, obovate, appressed-pubescent. Racemes about ⅓ as long as the leaves. Pods sickle- shaped, tomentose, torulose, ½ in. long. Red Sea Prov.; Berber Prov. (Barbadiap, Atbara); Blue Nile Prov. (J. Kon); Bahr El Ghazal Prov. (Shambé); Red Sea Prov. (Khor Aiet). =I. argentea= _Linn._ NIL BALADI—Arab. Much-branched shrub, silvery. Leaflets 9, silvery on both sides, obovate. Racemes of 12-20 yellow flowers. Pod falcate, terete, deflected, ½ in. long. Nubia; Bahr El Ghazal Prov. (Shambé). Yields an indigo. =I. arrecta= _Hochst._ Much-branched shrub, silky. Leaflets 13-17, oblanceolate, turn black when dried. Racemes of 6-12 yellow flowers. Pod deflexed, linear, up to ¾ in. long. Blue Nile Prov.; Darfur Prov. (J. Marra, near Gindi, 7,400 ft.); Bahr El Ghazal Prov. (Niamniam-land & Mittu-land). The chief Indigo producing plant in Africa, largely cultivated in Java. =I. tinctoria= _Linn._ Bushy shrub, 2-4 ft. high, with white appressed hairs. Leaflets 7-11; pod linear, cylindrical, apiculate. Khartoum Prov.; Blue Nile Prov. (Rufaa); Fung Prov.; Kordofan Prov. (El Obeid); Mongalla Prov. (Kenissa). Yields a large percentage of the Indigo of commerce. It is also suitable for green manure. =I. emarginella= _Steud._ Undershrub, 3-4 ft. high, almost glabrous. Leaflets 9, obovate, apex rounded, mucronate. Flowers yellow, in dense axillary conical racemes. Pod narrow-linear, deflexed, ¾ in. long. Bahr El Ghazal Prov. (Niamniam-land: by the Sueh River). =I. anabaptista= _Steud._ Branched shrub. Leaflets 3-5 oblong-oblanceolate up to 1 in. long, appressed-pilose. Racemes very short. Flowers and pods reflexed, the latter curved, flat, ¾ in. long, laxly pubescent. Red Sea Prov. (21° N.L.); Berber Prov. (Zeidab & Shendi); Fung Prov. (Jongol’s Post); Kordofan Prov. (Abu Gerad). =I. aspera= _Perr._ Herb, 1 ft. or more high. Leaflets 5, linear-lanceolate, silvery. Flowers pink, 20-30 in axillary racemes, 2-3 in. long. Pod deflexed, narrow-linear, 1 in. long. White Nile Prov. (J. Arashkol); Kordofan Prov. =I. arabica= _Jaub._ & _Spach._ Branched, bushy herb, silky. Leaflets 3-5 obovate, lateral ones often folded, with decurved point. Racemes axillary short, of 6-10 scarlet flowers. Pod linear-oblong, mucronate, subtorulose, under ½ in. long. White Nile Prov. =I. cordifolia= _Roth._ Bushy herb, 6-9 in. high, densely villous. Leaves simple, cordate-ovate. Flowers red, in dense axillary clusters, 3-6 together. Pods oblong, cuspidate, minute. Nubia; Blue Nile & Kordofan Provinces. =I. conjugata= _Baker_ Shrubby; branches almost 4-angled. Leaflets 3, the terminal one up to 2½ in. long and up to ½ in. broad. Racemes axillary; short-stalked, of 20 fl. and more. Cor. yellowish. Pod deflexed, linear, 1 in. long. White Nile Prov. =I. capitata= _Kotschy._ Shrub. Leaflets 7-9. Flowers in dense, rounded terminal heads, 1 in. broad; bracts pinnate. Pod oblong, small.