A. albida displays a number of unusual characters, some of which are peculiar to this species alone amongst the African acacias. A. albida differs in having eglandular petioles but a gland on the rhachis at the junction of each pair of pinnae, stamen-filaments which are shortly connate basally, large anthers which are eglandular even when in bud, and typically falcate or spirally coiled indehiscent pods. However, each of these characters may be found in other species of Acacia although in no other species are all of these characters associated together. Chevalier in Rev. Bot. Appl. Agric. Trop. 14 : 876 (1934) considered the species to be sufficiently distinct from all others to transfer it to the monotypic genus Faidherbia.
This is a large species, reaching 30 m in height, with spreading branches and a rounded crown. Bark: rough and dark brown or smooth and greenish grey; the young branches white to ashy, zigzagging characteristically between the nodes; stipules spinescent, the spines straight, quite short, only about 2 cm long, cream-coloured with brown tips. Leaves: bipinnate, clustered at the nodes, with 3-10 pairs of pinnae, each bearing 6-23 pairs of leaflets; leaflets quite large, 3.5-9 x 1-3 mm, grey-green; rachis 3-7.5 cm long with a gland between the pairs of pinnae; petiole 0.5-3.5 cm long, without a gland. Flowers: in slender, creamy white spikes, 4-14 cm long (May-Sept.). Fruit: an unusual pod, bright orange to reddish brown, thick, indehiscent, characteristically and conspicuously curled and twisted, large, up to 25 x 5 cm.
Arbre' atteignant 20 m de haut; cime étalée, à branches érigées, à port pyramidal-élancé; fût de 2-8 m de haut et de 1 m de diam., à base épaissie; écorce gris brun, lisse devenant profondément fissurée, brun clair et fibreuse en coupe; rameaux blancs à gris; épines stipulaires, droites, obliquement dressées, plus rarement dirigées vers le bas, atteignant 1,5 cm de long, blanches, grises à brunâtres.' Feuilles' gris vert et bleuté; pétiole et rachis de 2-4 cm de long, densément pubescents; pétiole de 0,6-1 cm de long; rachis muni d'une glande cupuliforme à l'insertion de chaque paire de pennes; pennes 3-10 paires, à rachis de 2-2,5 cm de long, éparsement pubescent; folioles 6-20 paires, à insertion sublatérale, linéaires-oblongues, tronquées à la base, obliquement arrondies et ± mucronées au sommet, de (3)5-8 mm de long, légèrement pubescentes; nervure primaire sublatérale.' Racèmes' spiciformes, de 5-10 cm de long; pédoncule de 2 cm de long, pubescent.' Fleurs' blanches, blanc crème devenant fauve, odorantes; calice de 1-1,5 mm de long, éparsement pubérulent; corolle de 3 mm de long.' Gousses' de 7,5-15 cm de long et de 1,5-3 cm de large.' Graines ovales-oblongues, de 5-10 mm de long, de 3,5-6 mm de large et de 2,5-3 mm d'épaisseur.
Tree, up to 30 m high. Stipules spinescent, straight or only slightly curved. Flowers in spikes. Pods orange or chestnut to reddish brown, falcate or curled into circular coil or variously twisted. Flowers yellowish white to cream.
Tree to 30 m high; trunk to 2 m diam.; crown rounded, branches spreading and frequently drooping to the ground in mature trees, young plants often irregularly branched and spindle-like. Bark dark brown to greenish-grey or ashen, rough; young branch-lets greenish-white or ashen, subglabrous to pubescent. Stipules spinescent, in pairs, up to 3.2 cm long, straight or slightly curved, greenish-white to light grey-brown, tips often reddish-brown when young; no prickles below the stipules. Leaves: petiole 0.5-3.7 cm long, adaxial gland absent; rhachis (1.3) 3-6(7.5) cm long, subglabrous or puberulous, with a single conspicuous gland at the junction of each of the 2(3)-10 pairs of pinnae; rhachillae (1.5)2.5-5.5(8.9) cm long; leaflets grey-green, 6-23 pairs per pinna, (2.5)4.5-9(13) x 0.75-3(5) mm, linear or linear-oblong to slightly obovate-oblong, apex rounded to subacute or mucronate, margin with or without white ciliolate hairs, glabrous or sparingly to densely appressed-pubescent ab-and/or adaxially. Inflorescences spicate, usually produced singly in the axil of a leaf, collectively forming a terminal panicle or raceme. Flowers yellowish-white to pale cream, sessile or to 0.5(2) mm pedicellate; spikes 3.5-15.7 cm long; peduncles (0.8)2-4(6.3) cm long, subglabrous to pubescent. Calyx campanulate, glabrous to pubescent, tube 0.5-1.8 mm long, lobes 0.3-0.7 mm long. Corolla often a delicate pink inside basally, tube 0.8-2.5 mm long, lobes divided almost to the base, up to 3 mm long, glabrous to pubescent. Stamen-filaments 4-6 mm long, shortly connate basally for ±1 mm; anthers 0.2-0.4 mm across, eglandular even in bud. Ovary 0.7-1.4 mm long, shortly stipitate, pilose; style glabrous or subglabrous. Pods bright orange to reddish-brown, falcate or curled into a circular coil or variously twisted, indehiscent, thick, 6-35 x (1.4)2-3.5(4.5) cm, glabrous or very rarely puberulous. Seeds light to dark brown, 9-12 x 4-8 mm, elliptic-lenticular; areole 6-9 x 4-6 mm, elliptic-lenticular.
Usually on alluvial floodplains, along dry watercourses, in riverine fringe forest, and around pans and swamps.
Riverine fringing vegetation and dry watercourses.
Found usually on alluvial floodplains, in riverine fringing vegetation, on the margins of pans or swamps or, in more arid localities, along dry watercourses or where a fairly high water table exists.
Sénégambie; Nigérie du Nord; s'étendant dans les régions sèches de l'Afrique du Nord à l'Égypte; Afrique orientale jusqu'au bassin du Zambèse; Transvaal
Widespread in tropical and subtropical Africa from Senegal, Gambia and Egypt southwards to South West Africa, Botswana, the Transvaal and Natal (Tongaland).
