Haplormosia monophylla (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Medicinal
Timber
Fuel
Conservation status

distribution in Africa (wild)

1, base of bole; 2, flowering twig; 3, fruit. Redrawn and adapted by Achmad Satiri Nurhaman

wood in transverse section

wood in tangential section

wood in radial section

Haplormosia monophylla (Harms) Harms

Protologue: Engl. & Drude, Veg. Erde 9, III, 1: 533 (1915).

Family: Papilionaceae (Leguminosae - Papilionoideae, Fabaceae)

Chromosome number: n = 10

Vernacular names

• Black gum (En).
• Chêne d’Afrique (Fr).

Origin and geographic distribution

Haplormosia monophylla occurs from Sierra Leone to Côte d’Ivoire, and from southern Nigeria to Cameroon and Gabon.

Uses

The wood (trade name: idewa) is used for furniture, cabinet work, flooring, interior trim, poles in house building, wharf piles, canoes and sliced veneer. In Liberia it is one of the favourite woods for carving. It is also suitable for heavy construction, mine props, ship building, vehicle bodies, handles, ladders, sporting goods, agricultural implements, railway sleepers and turnery. It is used for charcoal production.

Production and international trade

The timber is traded on the international market in small amounts under the name ‘idewa’, but statistics are not available. In trade it is probably often mixed with ‘afrormosia’, i.e. the wood of Pericopsis spp.

Properties

The heartwood is yellowish brown to chocolate brown and distinctly demarcated from the narrow, yellowish white sapwood. The grain is straight, sometimes interlocked, texture fine to moderately fine. The wood surfaces show a figure of fine brown and black bands. Polished wood surfaces are slightly lustrous.

The wood is heavy, with a density of (780–)800–950 (–1020) kg/m³ at 12% moisture content. It should be air dried slowly and with great care because of the high risk of distortion. In Liberia boards 2.5 cm thick air dry to 20% moisture content in about 3 months. The rates of shrinkage are moderate, from green to oven dry 3.0–3.4% radial and 6.7–7.3% tangential.

At 12% moisture content, the modulus of rupture is 141–186 N/mm², modulus of elasticity 13,600–17,200 N/mm², compression parallel to grain 70 N/mm², shear 11 N/mm², cleavage 21 N/mm and Chalais-Meudon side hardness 8.0.

Sawing and working of the wood is rather difficult; the blunting effect is fairly high and stellite-tipped saw teeth and tungsten-carbide-tipped cutting tools are recommended. The wood has a smooth finish and usually planes well, but sometimes with a slight picking up due to the presence of interlocked grain. It holds nails and screws well, but pre-boring is necessary. Gluing does not cause problems. The wood produces decorative sliced veneer. It is very durable, being resistant to termite, Lyctus and marine borer attacks. The wood is resistant to impregnation by preservatives.

Many phenolic compounds have been isolated from the heartwood. The root, stem bark and leaf blade have a high alkaloid content, the stem bark contains saponins, and the root bark contains tannins. The seed contains quinolizidine alkaloids of the sparteine/lupanine class.

Adulterations and substitutes

The wood resembles that of Pericopsis elata (Harms) Meeuwen which is used for similar purposes, but Haplormosia monophylla wood is slightly heavier and more difficult to work and dry.

Description

• Small to medium-sized tree up to 20(–30) m tall; bole branchless for up to 15 m, fairly straight, often low-branching, fluted or angular, up to 80(–100) cm in diameter, with short and thick buttresses at base often extending in thick surface roots; bark surface smooth to slightly furrowed and thin-scaly, greyish brown, inner bark fibrous, yellow-orange, with conspicuous ripple marks; crown compact, much-branched with ascending branches; young shoots sparsely short-hairy, soon glabrous.
• Leaves alternate, simple and entire; stipules minute, triangular; petiole 1.5–4 cm long, jointed at base and top, with 2 small stipels just below the top; blade elliptical to obovate, 4.5–15(–20) cm × 3.5–6.5(–9) cm, base obtuse to slightly cuneate, apex obtuse to shortly acuminate, leathery, glabrous, glossy, pinnately veined with 5–9 pairs of lateral veins.
• Inflorescence an axillary few-flowered raceme up to 12 cm long, nearly glabrous; bracts ovate, up to 1.5 mm long.
• Flowers bisexual, papilionaceous; pedicel 8–12 mm long; calyx cup-shaped, tube c. 3 mm long, lobes 3–5 mm long, upper 2 fused, glabrous outside, woolly hairy inside; corolla purplish blue, with transversely elliptical standard 12–15 mm × 15–20 mm, wings and keel 12–15 mm long; stamens 10, free, 10–13 mm long; ovary superior, 3–4 mm long, shortly stiped, flattened, 1-celled, style curved, c. 7 mm long.
• Fruit an elliptical-obovate, flattened pod 5–8 cm × 4–5 cm, with c. 5 mm long stipe at base and short point at apex, thickly leathery, glabrous, dehiscent, 1-seeded.
• Seed oblong, 4–5 cm × 2–3 cm, completely enveloped by an aril.
• Seedling with epigeal germination; hypocotyl 1.5–2 cm long, densely hairy, epicotyl c. 7 cm long, sparsely hairy; cotyledons thick and fleshy; first c. 10 leaves scale-like.

Other botanical information

Haplormosia comprises a single species. It seems related to Ormosia from tropical America, Asia and Australia and Pericopsis from tropical Africa and Asia.

Anatomy

Wood-anatomical description (IAWA hardwood codes):

• Growth rings: 2: growth ring boundaries indistinct or absent.
• Vessels: 5: wood diffuse-porous; 13: simple perforation plates; 22: intervessel pits alternate; 23: shape of alternate pits polygonal; 26: intervessel pits medium (7–10 μm); 27: intervessel pits large (≥ 10 μm); 29: vestured pits; 30: vessel-ray pits with distinct borders; similar to intervessel pits in size and shape throughout the ray cell; 42: mean tangential diameter of vessel lumina 100–200 μm; 46: ≤ 5 vessels per square millimetre; 47: 5–20 vessels per square millimetre; 58: gums and other deposits in heartwood vessels.
• Tracheids and fibres: 61: fibres with simple to minutely bordered pits; 66: non-septate fibres present; 70: fibres very thick-walled.
• Axial parenchyma: 80: axial parenchyma aliform; 82: axial parenchyma winged-aliform; 83: axial parenchyma confluent; (84: axial parenchyma unilateral paratracheal); 85: axial parenchyma bands more than three cells wide; 91: two cells per parenchyma strand; 92: four (3–4) cells per parenchyma strand.
• Rays: 97: ray width 1–3 cells; 104: all ray cells procumbent; 115: 4–12 rays per mm; 116: ≥ 12 rays per mm.
• Storied structure: 118: all rays storied; 120: axial parenchyma and/or vessel elements storied.
• Mineral inclusions: 136: prismatic crystals present; 142: prismatic crystals in chambered axial parenchyma cells.

(P. Ng’andwe, H. Beeckman & P.E. Gasson)

Growth and development

In Liberia and Côte d’Ivoire the tree is briefly deciduous in November–December and it flowers in April. New leaves are brilliant red. Fruits mature in about 6 months. No information on nodulation is available.

Ecology

Haplormosia monophylla characteristically occurs along river banks and in swampy valleys in lowland evergreen forest, where it locally grows in groups. However, larger-sized trees are often found isolated in the forest at some distance from water courses.

Propagation and planting

Natural regeneration may be abundant on sandy river banks, but it is apparently rare in more closed forest.

Harvesting

The trees are difficult to fell with traditional tools because of the hard wood.

Handling after harvest

The logs do not float in water and consequently cannot be transported by river.

Genetic resources

Haplormosia monophylla is fairly widespread in West and Central Africa, but in most regions it is uncommon and it is selectively felled for its timber. It is expected that overexploitation and habitat degradation will result in serious population decline in the near future, and therefore Haplormosia monophylla has been included in the IUCN Red list as vulnerable.

Prospects

Although Haplormosia monophylla provides a good-quality timber, its prospects as a commercial timber are poor because the supplies are very limited. This is mainly due to the scattered occurrence, especially of larger-sized trees. Information is lacking on growth rates and propagation.

Major references

• ATIBT (Association Technique Internationale des Bois Tropicaux), 1986. Tropical timber atlas: Part 1 – Africa. ATIBT, Paris, France. 208 pp.

• Aubréville, A., 1959. La flore forestière de la Côte d’Ivoire. Deuxième édition révisée. Tome premier. Publication No 15. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 369 pp.

• 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.

• 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.

• de Saint-Aubin, G., 1963. La forêt du Gabon. Publication No 21 du Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 208 pp.

• Dudek, S., Förster, B. & Klissenbauer, K., 1981. Lesser known Liberian timber species. Description of physical and mechanical properties, natural durability, treatability, workability and suggested uses. GTZ, Eschborn, Germany. 168 pp.

• Raponda-Walker, A. & Sillans, R., 1961. Les plantes utiles du Gabon. Paul Lechevalier, Paris, France. 614 pp.

• Takahashi, A., 1978. Compilation of data on the mechanical properties of foreign woods (part 3) Africa. Shimane University, Matsue, Japan, 248 pp.

• Voorhoeve, A.G., 1979. Liberian high forest trees. A systematic botanical study of the 75 most important or frequent high forest trees, with reference to numerous related species. Agricultural Research Reports 652, 2nd Impression. Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands. 416 pp.

Other references

• Bouquet, A. & Debray, M., 1974. Plantes médicinales de la Côte d’Ivoire. Travaux et Documents No 32. ORSTOM, Paris, France. 231 pp.

• Hepper, F.N., 1958. Papilionaceae. 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. 505–587.

• InsideWood, undated. [Internet] http://insidewood.lib.ncsu.edu/search/. May 2007.

• Keay, R.W.J., 1989. Trees of Nigeria. A revised version of Nigerian trees (1960, 1964) by R.W.J. Keay, C.F.A. Onochie and D.P. Stanfield. Clarendon Press, Oxford, United Kingdom. 476 pp.

• Kinghorn, A.D., Hussain, R.A., Robbins, E.F., Balandrin, M.F., Stirton, C.H. & Evans, S.V., 1988. Alkaloid distribution in seeds of Ormosia, Pericopsis and Haplormosia. Phytochemistry 27(2): 439-444.

• Kryn, J.M. & Fobes, E.W., 1959. The woods of Liberia. Report 2159. USDA Forest Service, Forest Products Laboratory, Madison, Wisconsin, United States. 147 pp.

• Lewis, G., Schrire, B., MacKinder, B. & Lock, M., 2005. Legumes of the world. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 577 pp.

• Normand, D., 1950. Atlas des bois de la Côte d’Ivoire. Tome 1. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 148 pp.

• Normand, D. & Paquis, J., 1976. Manuel d’identification des bois commerciaux. Tome 2. Afrique guinéo-congolaise. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 335 pp.

• Sallenave, P., 1971. Propriétés physiques et mecaniques des bois tropicaux. Deuxième supplément. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 128 pp.

Sources of illustration

• Voorhoeve, A.G., 1979. Liberian high forest trees. A systematic botanical study of the 75 most important or frequent high forest trees, with reference to numerous related species. Agricultural Research Reports 652, 2nd Impression. Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands. 416 pp.

Author(s)

• R.H.M.J. Lemmens, PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article

Lemmens, R.H.M.J., 2008. Haplormosia monophylla (Harms) Harms. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. Accessed 31 March 2025.

• See the Prota4U database.