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Sideroxylon inerme L.

Sp. pl. 1: 192 (1753).
Chromosome number
2n = 44
Vernacular names
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.
Major references
• Coates Palgrave, K., 1983. Trees of southern Africa. 2nd Edition. Struik Publishers, Cape Town, South Africa. 959 pp.
• Friis, I., 2006. Sapotaceae In: Thulin, M. (Editor). Flora of Somalia. Volume 3. Angiospermae (cont.). Royal Botanic Gardens, Kew, Richmond, United Kingdom. p. 12–18.
• Kupicha, F.K., 1983. Sapotaceae. In: Launert, E. (Editor). Flora Zambesiaca. Volume 7, part 1. Flora Zambesiaca Managing Committee, London, United Kingdom. pp. 210–247.
• Lovett, J.C., Ruffo, C.K., Gereau, R.E. & Taplin, J.R.D., 2006. Field guide to the moist forest trees of Tanzania. [Internet] Centre for Ecology Law and Policy, Environment Department, University of York, York, United Kingdom. res/celp/webpages/projects/ecology/ tree%20guide/guide.htm. Accessed June 2006.
• Pennington, T.D., 1991. The genera of Sapotaceae. Royal Botanic Gardens, Kew, Richmond, United Kingdom and the New York Botanical Garden, New York, United States. 295 pp.
Other references
• Beentje, H.J., 1994. Kenya trees, shrubs and lianas. National Museums of Kenya, Nairobi, Kenya. 722 pp.
• Bosman, F., 2006. Sideroxylon inerme L. subsp. inerme. [Internet] South African National Biodiversity Institute, Cape Town, South Africa. plantqrs/sideroxinerm.htm. Accessed October 2006.
• Friedmann, F., 1981. Sapotacées. In: Bosser, J., Cadet, T., Guého, J. & Marais, W. (Editors). Flore des Mascareignes. Familles 111–120. The Sugar Industry Research Institute, Mauritius, l’Office de la Recherche Scientifique Outre-Mer, Paris, France & Royal Botanic Gardens, Kew, Richmond, United Kingdom. 27 pp.
• Hemsley, J.H., 1968. Sapotaceae. In: Milne-Redhead, E. & Polhill, R.M. (Editors). Flora of Tropical East Africa. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. 79 pp.
• Holmes, P.M. & Cowling, R.M., 1993. Effects of shade on seedling growth, morphology and leaf photosynthesis in six subtropical thicket species from the eastern Cape, South Africa. Forest Ecology and Management 61(3–4): 199–220.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Sharma, P. & Singh, G., 2002. A review of plant species used to treat conjunctivitis. Phytotherapy Research 16: 1–22.
• Turpie, J.K., 2000. The use and value of natural resources of the Rufiji floodplain and delta, Tanzania. Technical report No 17. Rufiji Environment Management Project, Dar es Salaam, Tanzania. 87 pp.
• van Vuuren, N.J.J., Banks, C.H. & Stohr, H.P., 1978. Shrinkage and density of timbers used in the Republic of South Africa. Bulletin No 57. South African Forestry Research Institute, Pretoria, South Africa. 55 pp.
• van Wyk, B. & van Wyk, P., 1997. Field guide to trees of southern Africa. Struik Publishers, Cape Town, South Africa. 536 pp.
M. Brink
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

D. Louppe
CIRAD, Département Environnements et Sociétés, Cirad es-dir, Campus international de Baillarguet, TA C-DIR / B (Bât. C, Bur. 113), 34398 Montpellier Cedex 5, France
A.A. Oteng-Amoako
Forestry Research Institute of Ghana (FORIG), University P.O. Box 63, KNUST, Kumasi, Ghana
M. Brink
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
General editors
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
J.R. Cobbinah
Forestry Research Institute of Ghana (FORIG), University P.O. Box 63, KNUST, Kumasi, Ghana
Photo editor
G.H. Schmelzer
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

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.
leafy branche
obtained from

fruiting branch
obtained from

wood in transverse section

wood in tangential section

wood in radial section