Prota 7(1): Timbers/Bois d’œuvre 1
Bol. Soc. Brot., ser. 2, 29: 42 (1955).
Mimosaceae (Leguminosae - Mimosoideae)
2n = 28
Amblygonocarpus obtusangulus (Welw. ex Oliv.) Harms (1899), Amblygonocarpus schweinfurthii Harms (1899).
Origin and geographic distribution
Amblygonocarpus andongensis occurs in the savanna zone from northern Ghana east to Sudan, through Uganda and Tanzania, south to Botswana, Zimbabwe and Mozambique.
The wood, known in southern Africa as ‘bangawanga’, is used for joinery and furniture. It is considered excellent for heavy duty flooring and for railway sleepers, and is also suitable for construction, mine props, vehicle bodies, sporting goods, agricultural implements, poles and piles, and vats. The wood is also used as firewood and for charcoal production.
Various plant parts are used in local medicine: a root decoction is administered as an emetic to treat food poisoning, against colic and cough and as a vermifuge, the bark is used as an antidote for snakebites, a bark decoction is applied to sores, a leaf extract is used to treat stomach-ache, and pulverized pods are applied to ulcers and also used as a fish poison. Roasted seeds are eaten. Boiled and fermented seeds are used as a condiment, e.g. in Cameroon, although they are hard to prepare and used in small amounts.
Production and international trade
The wood of Amblygonocarpus andongensis is mainly locally used; small quantities of sawn wood have been exported from Mozambique.
The heartwood is dark brown or red-brown, darkening on exposure, and distinctly demarcated from the narrow grey-white sapwood. The grain is wavy or straight, sometimes slightly interlocked, texture fine and even.
The wood has a density of 910–1090 kg/m³ at 15% moisture content. Shrinkage rates are 2.3% radial and 2.7% tangential from green to 12% moisture content. The wood air-dries slowly, with some surface checking, but it is stable in service. The wood is difficult to saw and work; blunting of cutting edges is common. It can be finished to an excellent surface, is resistant to abrasion, and has good gluing properties. Pre-boring is necessary for screws and nails. The wood is durable and termite-resistant; it is resistant to impregnation with preservatives. Charcoal made from the wood is considered excellent for iron-forge work.
The seeds contain about 12% oil, with a high proportion of linoleic acid. The inner bark, roots and seeds have been recorded to be poisonous, but are used in various medicinal or food preparations.
Small to medium-sized tree up to 20(–25) m tall, glabrous; bole straight, branchless for up to 10 m, up to 90 cm in diameter, without buttresses; bark scaly, greyish brown to blackish. Leaves alternate, bipinnately compound, with 2–5(–6) pairs of pinnae; petiole 4–9 cm long, rachis 2–18 cm long; leaflets alternate, shortly stalked, 11–21 per pinna, elliptical to obovate-elliptical, 1–3 cm × 0.5–2 cm, usually notched at apex. Inflorescence an axillary raceme (3–)6–18 cm long; peduncle 1–4.5 cm long. Flowers bisexual, regular, 5-merous, white; pedicel 1.5–3.5(–5) mm long; calyx 0.5–1 mm long, toothed; petals free, elliptical, 3–5 mm × 1–1.5 mm; stamens 10, with filaments 5–6 mm long; ovary superior, oblong, shortly stalked, 1-celled, style slender, curved near apex. Fruit an oblong indehiscent pod 8–17(–20) cm × 2–3.5 cm, usually bluntly tetragonal in section, woody, brown, glossy, septate between the seeds, c. 10-seeded. Seeds 10–13 mm × 7–8 mm, slightly flattened, hard, brown.
Amblygonocarpus comprises a single species. It resembles Tetrapleura, which differs in its pod valves that are only thickened in a band and in its glandular anthers.
Amblygonocarpus andongensis occurs in deciduous woodland and savanna up to 1350 m altitude.
Genetic resources and breeding
Amblygonocarpus andongensis is widespread and locally common. There is no reason to consider it endangered.
Amblygonocarpus andongensis is a multipurpose tree with favourable wood and charcoal qualities. Its applications as food and in traditional medicine merit more research.
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Correct citation of this article:
Lemmens, R.H.M.J., 2006. Amblygonocarpus andongensis (Welw. ex Oliv.) Exell & Torre. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
1, leaf; 2, inflorescence; 3, flower; 4, fruit.
Source: Flore analytique du Bénin
obtained from Zimbabweflora
obtained from Zimbabweflora
obtained from Zimbabweflora
wood in transverse section
wood in tangential section