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Fillaeopsis discophora Harms

Bot. Jahrb. Syst. 26: 259 (1899).
Mimosaceae (Leguminosae - Mimosoideae)
Vernacular names
Arbre à semelle (Fr).
Origin and geographic distribution
Fillaeopsis discophora occurs from Nigeria east to the Central African Republic and DR Congo, and south to northern Angola.
The wood (trade name: nieuk) is suitable for indoor as well as outdoor construction, flooring, doors and window frames. It can also be used for construction under water and railway sleepers, but treatment with preservatives is recommended for these purposes. The bark is used as an analgesic in local medicine in Gabon, and a bark decoction is used in Congo externally to treat sores, rheumatism and rickets.
The heartwood is pinkish brown with a glossy appearance and often with orange-brown streaks, and distinctly demarcated from the yellowish white sapwood, which becomes greyish upon drying. The grain is more or less interlocked, texture moderately coarse. The wood is medium-weight, with a density of 485–640 kg/m³ at 12% moisture content. Shrinkage rates from green to oven dry are 3.1–4.3% radial and 5.6–8.5% tangential. Air drying usually causes few defects, but oven drying may cause deformation due to the presence of interlocked grain.
At 12% moisture content, the modulus of rupture is 60–120 N/mm², modulus of elasticity 8100–11,700 N/mm², compression parallel to grain 33–46 N/mm², shear 5.5–7.2 N/mm², cleavage 9.8–19.3 N/mm and Chalais Meudon side hardness 1.8–2.9.
The wood is moderately difficult to saw; stellite-tipped sawteeth are recommended. Planing to a smooth surface is possible using sharp tools. Nailing and screwing are satisfactory, and the gluing properties are good. The wood takes paint and varnish well. The peeling properties are excellent, comparable with okoumé (Aucoumea klaineana Pierre), and good-quality plywood can be produced. The wood is only moderately durable, being rather susceptible to fungal attack. The wood is fairly permeable to preservatives.
The root bark, young shoots and seeds have an onion-like scent. The presence of saponins in large amounts has been reported for the bark.
Medium-sized to fairly large evergreen tree up to 40 m tall; bole up to 110(–150) cm in diameter, cylindrical but often sinuous and sometimes fluted, with thick buttresses up to 4 m high; bark flaky, dark brown to reddish brown; crown often open and spreading, irregular, with few large branches; branches dark brown, with lenticels. Leaves alternate, bipinnately compound, with 1–2 pairs of pinnae; petiole 2.5–9.5 cm long, rachis up to 12 cm long; leaflets 4–8(–10) per pinna, alternate, shortly stalked, elliptical to ovate, 3–10 cm × 1.5–5 cm, usually acuminate at apex, glabrous. Inflorescence an axillary panicle consisting of several many-flowered spikes. Flowers bisexual, regular, 5-merous, white, sessile; sepals 1–1.5 mm long, fused to halfway; petals free, elliptical, 2.5–3 mm long; stamens 10, free, 4–5 mm long, filaments hairy in basal part, anthers with a stalked gland; ovary superior, oblong-ellipsoid, 1.5–2 mm long, 1-celled, style filiform, 2–2.5 mm long. Fruit a flattened, broadly ellipsoid-oblong, papery pod 20–60 cm × 10–18 cm, with thickened margins and a reticulate pattern of veins on the sides, pale to medium brown, dehiscent, many-seeded. Seeds oblong, strongly flattened, with wing all around, 5–17 cm × 3.5–5 cm, pale brown. Seedling with hypogeal germination.
Fillaeopsis comprises a single species and seems related to Newtonia, but it has also been suggested that it is close to Prosopis based on DNA sequence data.
Fillaeopsis discophora occurs in lowland rainforest. It can be found scattered in primary forest, but may be locally fairly abundant in former large forest gaps.
In 1974 the standing wood volume of Fillaeopsis discophora trees with a bole diameter of over 60 cm in north-eastern Gabon was estimated to be 0.64 m³/ha. The logs are not very susceptible to fungal and insect attacks and do not need preservative treatment when left for a limited time in the forest after felling.
Genetic resources and breeding
Fillaeopsis discophora is fairly widespread, although it occurs scattered and in rather low densities. It does not seem to be in direct danger of genetic erosion.
The wood of Fillaeopsis discophora is best suited for rotary peeling, but its properties for use in joinery are much less favourable. Too little is known about the ecological requirements, regeneration and growth rates to evaluate the possibilities of Fillaeopsis discophora in sustainably managed natural production forest.
Major references
• Burkill, H.M., 1995. The useful plants of West Tropical Africa. 2nd Edition. Volume 3, Families J–L. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 857 pp.
• Villiers, J.-F., 1989. Leguminosae - Mimosoideae. Flore du Gabon. Volume 31. Muséum National d’Histoire Naturelle, Paris, France. 185 pp.
• Wilks, C. & Issembé, Y., 2000. Les arbres de la Guinée Equatoriale: Guide pratique d’identification: région continentale. Projet CUREF, Bata, Guinée Equatoriale. 546 pp.
• Yvon, J., 1975. Le nieuk. Bois et Forêts des Tropiques 159: 73–76.
Other references
• de Saint-Aubin, G., 1963. La forêt du Gabon. Publication No 21 du Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 208 pp.
• Gilbert, G. & Boutique, R., 1952. Mimosaceae. In: Robyns, W., Staner, P., Demaret, F., Germain, R., Gilbert, G., Hauman, L., Homès, M., Jurion, F., Lebrun, J., Vanden Abeele, M. & Boutique, R. (Editors). Flore du Congo belge et du Ruanda-Urundi. Spermatophytes. Volume 3. Institut National pour l’Étude Agronomique du Congo belge, Brussels, Belgium. pp. 137–233.
• Keay, R.W.J., 1958. Mimosaceae. In: Keay, R.W.J. (Editor). Flora of West Tropical Africa. Volume 1, part 2. 2nd Edition. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. pp. 484–504.
• Lewis, G., Schrire, B., MacKinder, B. & Lock, M., 2005. Legumes of the world. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 577 pp.
• Raponda-Walker, A. & Sillans, R., 1961. Les plantes utiles du Gabon. Paul Lechevalier, Paris, France. 614 pp.
• Sulaiman, S.F., Culham, A. & Harborne, J.B., 2003. Molecular phylogeny of Fabaceae based on rbcL sequence data: with special emphasis on the tribe Mimoseae (Mimosoideae). Asia Pacific Journal of Molecular Biology and Biotechnology 11(1): 9–35.
• Takahashi, A., 1978. Compilation of data on the mechanical properties of foreign woods (part 3) Africa. Shimane University, Matsue, Japan, 248 pp.
• White, L. & Abernethy, K., 1997. A guide to the vegetation of the Lopé Reserve, Gabon. 2nd edition. Wildlife Conservation Society, New York, United States. 224 pp.
R.H.M.J. Lemmens
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:
Lemmens, R.H.M.J., 2007. Fillaeopsis discophora Harms. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
wood in transverse section

wood in tangential section