Heywoodia lucens (PROTA)
 |
Introduction |
| General importance |  
|
| Geographic coverage Africa |
|
| Geographic coverage World |
|
| Timber |
|
| Fuel |
|
| Conservation status |
|
Heywoodia lucens Sim
- Protologue: For. fl. Cape: 326 (1907).
- Family: Euphorbiaceae (APG: Phyllanthaceae)
Vernacular names
- Stink ebony, Cape ebony (En).
Origin and geographic distribution
Heywoodia lucens has a disjunct distribution, occurring from Kenya and Uganda to northern Tanzania, and then again more than 2600 km to the south from the southern part of Mozambique to northern and eastern South Africa and Swaziland.
Uses
The wood, known as ‘Cape ebony’ or ‘stink ebony’ in South Africa, is used for poles, agricultural implements, sledges, tool handles and wooden spoons. It is suitable for heavy construction, flooring, joinery, interior trim, furniture, railway sleepers, toys, novelties and veneer, and also for precision and musical instruments. It is used as firewood and for charcoal production.
Production and international trade
The wood of Heywoodia lucens is only traded locally.
Properties
The heartwood is dark purplish to nearly black, and distinctly demarcated from the narrow sapwood. The grain is usually straight, texture coarse and even. The wood has a foetid smell. It is heavy, with a density of South-African wood in green condition (at 51% moisture content) of 1010–1140 kg/m³ and at 10% moisture content of 780–960 kg/m³. It is hard and strong. The rates of shrinkage are moderate, from green to oven dry 4.7% radial and 7.0% tangential. At 12% moisture content, the modulus of rupture is 121 N/mm², modulus of elasticity 13,820 N/mm², compression parallel to grain 64 N/mm², shear 16 N/mm², Janka side hardness 9515 N and Janka end hardness 12,045 N.
Notwithstanding its high density and hardness, the wood works fairly well. Upon finishing, it takes a nice polish and is especially lustrous when quarter-sawn. It produces sliced veneer of good quality. The wood is moderately durable, being moderately resistant to termites and other insects, but the sapwood is susceptible to Lyctus attack. The heartwood is moderately resistant to impregnation with preservatives.
Description
- Evergreen, dioecious, medium-sized tree up to 30 m tall; bole cylindrical, up to 100(–150) cm in diameter; bark silvery green to grey-brown or dark brown, irregularly peeling in thin, patchy pieces c. 5 cm long; crown much-branched; twigs 4-angled at first, soon becoming rounded, glabrous, pale greyish brown.
- Leaves alternate, simple and entire; stipules triangular, 1–1.5 mm long, early caducous; petiole 1–2(–4) cm long; blade broadly ovate to elliptical-ovate, 4–15(–25) cm × 2–12(–15) cm, cuneate to rounded or truncate at base, short-acuminate at apex, leathery, glabrous, pinnately veined with 5–8(–13) pairs of lateral veins.
- Inflorescence an axillary fascicle, many-flowered in male inflorescence, 1–3-flowered in female one, glabrous; bracts up to 4, transversely ovate, c. 1 mm × 1.5 mm, margin irregularly toothed.
- Flowers unisexual, regular, greenish; sepals (2–)3, free, resembling the bracts but slightly larger; petals 5(–6), free, elliptical-oblong, 2–2.5 mm long; disk slightly lobed; male flowers sessile, stamens (8–)10–11(–12), free, in 2 whorls, c. 3 mm long, rudimentary ovary minute; female flowers with 3–5 mm long pedicel, rudimentary stamens c. 1 mm long, ovary superior, ovoid to globose, c. 1.5 mm long, 4–5-celled, with 4–5 sessile, 2-lobed stigmas.
- Fruit a slightly depressed globose, shallowly 8–10-lobed capsule c. 1 cm × 1.5 cm, greenish, splitting in 4–5 parts, each splitting again into 2, up to 5-seeded.
- Seeds obliquely ovoid, 7–8 mm × 5–6 mm, smooth, pale brown to dark brown.
Other botanical information
The leaves of juvenile trees are slightly peltate, with the stalk not attached to the margin of the leaf blade but to the lower surface. The flowering period of trees seems to be quite long, and fruit in various stages of development can be found on a tree at one time. Heywoodia comprises a single species.
Ecology
In East Africa Heywoodia lucens occurs in evergreen forest, riverine forest or the slightly drier parts of swamp forest, at 1150–1800 m altitude. It is often found on termite mounds, and is commonly dominant or may even form pure stands. In southern Africa it inhabits coastal evergreen forest, often growing on river banks, up to 600 m altitude. Heywoodia lucens often grows gregariously in rather small groups of trees. In South Africa it is usually found on fairly dry, sandy soils.
Management
Studies in eastern South Africa indicate that regeneration of Heywoodia lucens is poor, although it has also been reported that young trees are common in the deep shade of adult trees. Heywoodia lucens probably does not coppice.
Genetic resources
Heywoodia lucens has a wide although disjunct distribution, and there are no indications that it is subject to genetic erosion. However, in Swaziland it is considered endangered. In coastal forest in South Africa, it is locally heavily exploited in communal forests, but common in state forests.
Prospects
The heavy, hard and strong, but foetid smelling wood is likely to remain of local importance. Too little is known on growth rates, ecological requirements and regeneration of Heywoodia lucens to assess its prospects as a commercial timber tree in sustainably managed forest.
Major references
- Bolza, E. & Keating, W.G., 1972. African timbers: the properties, uses and characteristics of 700 species. Division of Building Research, CSIRO, Melbourne, Australia. 710 pp.
- Coates Palgrave, K., 2002. Trees of southern Africa. 3rd Edition. Struik Publishers, Cape Town, South Africa. 1212 pp.
- Milne-Redhead, E., 1957. Heywoodia lucens Sim, a tree new to tropical Africa. Bulletin du Jardin Botanique de l’Etat 27(2): 327–333.
- Palmer, E. & Pitman, N., 1972–1974. Trees of southern Africa, covering all known indigenous species in the Republic of South Africa, South-West Africa, Botswana, Lesotho and Swaziland. 3 volumes. Balkema, Cape Town, South Africa. 2235 pp.
- Radcliffe-Smith, A., 1987. Euphorbiaceae (part 1). In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 407 pp.
Other references
- Lovett, J.C., Ruffo, C.K. & Gereau, R.E., 2003. Field guide to the moist forest trees of Tanzania. [Internet] Centre for Ecology Law and Policy, Environment Department, University of York, York, United Kingdom. 192 pp. http://www.cepf.net/ Documents/Final_LovettRuffoGereau_FieldGuide.pdf. July 2010.
- Obiri, J.A.F. & Lawes, M.J., 2004. Chance versus determinism in canopy gap regeneration in coastal scarp forest in South Africa. Journal of Vegetation Science 15: 539–547.
- Obiri, J., Lawes, M. & Mukolwe, M., 2002. The dynamics and sustainable use of high-value tree species of the coastal Pondoland forests of the Eastern Cape Province, South Africa. Forest Ecology and Management 166(1–3): 131–148.
- Radcliffe-Smith, A., 1995. Additions and corrections to ‘Euphorbiaceae’ for ‘Flora of Tropical East Africa’. Kew Bulletin 50(4): 809–816.
- Radcliffe-Smith, A., 1996. Euphorbiaceae, subfamilies Phyllantoideae, Oldfieldioideae, Acalyphoideae, Crotonoideae and Euphorbioideae, tribe Hippomaneae. In: Pope, G.V. (Editor). Flora Zambesiaca. Volume 9, part 4. Royal Botanic Gardens, Kew, Richmond, United Kingdom. pp. 1–337.
- Takahashi, A., 1978. Compilation of data on the mechanical properties of foreign woods (part 3) Africa. Shimane University, Matsue, Japan. 248 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.
Author(s)
- L.P.A. Oyen, PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
Correct citation of this article
Oyen, L.P.A., 2011. Heywoodia lucens Sim. In: Lemmens, R.H.M.J., Louppe, D. & Oteng-Amoako, A.A. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. Accessed 23 April 2026.
- See the Prota4U database.