Prota 7(1): Timbers/Bois d’œuvre 1
Sp. pl. 1: 192 (1753).
2n = 44
White milkwood (En). Mkoko bara, mgongonga, mtunda wa ngombe, mchocha mwitu (Sw).
Origin and geographic distribution
Sideroxylon inerme is distributed along the eastern coast of Africa, from Somalia southwards to South Africa, and on Aldabra Island (Seychelles) and Mayotte; it occurs sporadically more inland.
The wood of Sideroxylon inerme is used for poles and for making spoons, and has been used for house construction and for building boats, bridges and mills. It is also used as firewood and for charcoal making.
The fruits are sometimes eaten. In traditional African medicine the roasted powdered root is mixed with oil from the seed of Trichilia emetica Vahl and rubbed into incisions over fractured limbs. A decoction of the root, administered as an enema, is a diaphoretic. The dried pulverized root is eaten to treat conjunctivitis. An infusion of the bark is taken against nightmares. A decoction of the bark is given to treat gall sickness in animals.
The wood is yellowish brown with a fine texture. It is heavy (density 1040 kg/m³ at 10% moisture content), hard, strong and durable, even in damp circumstances.
Spreading, much-branched, evergreen shrub or small tree up to 15 m tall, often with a gnarled appearance, with scarce milky latex; bark grey, brown or black, fissured; young branches covered with fine soft grey to rusty hairs, older branches glabrous. Leaves spirally arranged or less frequently opposite, simple and entire; stipules absent; petiole 0.5–2 cm long, rusty hairy when young, glabrous later; blade elliptical to obovate, (3–)4–12(–15) cm × (1.5–) 2–6(–7.5) cm, base narrowly cuneate, apex obtuse to rounded or notched, thickly leathery, often with rusty hairs disappearing with age, pinnately veined with indistinct lateral veins. Inflorescence a congested fascicle in leaf axils. Flowers usually bisexual, regular, 5-merous, with an unpleasant smell; pedicel up to 7 mm long, shortly hairy; sepals broadly ovate, up to 2.5 mm long, slightly hairy or glabrous outside; corolla campanulate, up to 5 mm in diameter, whitish, cream-coloured or greenish, tube up to 1.5 mm long, lobes ovate and up to 2.5 mm long; stamens opposite corolla lobes, up to 5 mm long, alternating with petaloid, ovate to lanceolate staminodes 1.5–3 mm long; ovary superior, globose, hairy, 5-celled, style up to 1.5 mm long. Fruit a globose berry 6–15 mm in diameter, with persistent style, ripening purplish black, smooth, pulp fleshy, sticky, 1-seeded. Seed globose, 5–9 mm in diameter, testa thick and woody, cream-coloured or brown, shiny, with 5 longitudinal ridges and 2–4 small pits near the basal scar.
In southern Africa Sideroxylon inerme flowers in January–July; fruiting is in July–January. Seed dispersal is by birds. Sideroxylon inerme can become very old: the tree known as ‘Post Office tree’ in Mossel Bay (South Africa) is more than 500 years old.
Within Sideroxylon inerme 3 subspecies are distinguished: subsp. diospyroides (Baker) J.H.Hemsl., distributed in Somalia, Kenya, Tanzania, Zimbabwe and Mozambique; subsp. inerme , occurring in Mozambique and South Africa; and subsp. cryptophlebium (Baker) J.H.Hemsl. occurring on Aldabra Island (Seychelles).
Sideroxylon comprises about 50 species in tropical America and about 25 species in the Old World (6 in mainland Africa, about 6 in Madagascar, 8 in the Mascarene islands, and 5 in Asia). Sideroxylon puberulum DC., a tree up to 15 m tall with a bole diameter up to 60 cm, is endemic to Mauritius, where it is known as ‘manglier rouge’. Its wood is heavy and durable and is used for making poles, planks and keels of boats. The wood of Sideroxylon sessiliflorum (Poir.) Capuron, a rather rare endemic of Mauritius, has been described as very good for cabinet work.
Sideroxylon inerme is essentially a tree of coastal woodland and littoral forest. It is a common component of shrub thickets on the seashore near the high-water mark and is found along landward fringes of mangroves. It sometimes occurs further inland along rivers and in open woodland, up to 1500 m altitude, often on termite mounds. It occurs in regions with an average annual rainfall of 300–1500 mm and tolerates shade and wind.
Sideroxylon inerme is easily propagated by seeds, which take 4–6 weeks to germinate. Vegetative propagation using cuttings is also possible, but only semi-mature side shoots should be used; cuttings normally root in 6–8 weeks.
Genetic resources and breeding
It is unclear to what extent Sideroxylon inerme is threatened by genetic erosion in tropical Africa. It is protected in South Africa, where even for pruning a permit is required; 3 specimens have been declared National Monuments in South Africa.
The wood of Sideroxylon inerme is hard, strong and durable, but little information on the wood properties is available. In view of the small size of the tree and the uncertain conservation status of the species, increased importance as a source of timber is not to be expected. Sideroxylon inerme does not easily catch fire and plantings could be useful as a firebreak.
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Correct citation of this article:
Brink, M., 2007. Sideroxylon inerme L. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
obtained from Zimbabweflora
obtained from Zimbabweflora
wood in transverse section
wood in tangential section
wood in radial section