Xylia evansii (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Fruit
Spice / condiment
Medicinal
Timber
Fibre
Food security

various parts of the tree (Virtual Field Herbarium)

Xylia evansii Hutch.

Protologue: Bull. Misc. Inform. Kew 1908: 258 (1908).

Family: Mimosaceae (Leguminosae - Mimosoideae)

Chromosome number: 2n = 24

Origin and geographic distribution

Xylia evansii occurs from Sierra Leone to Ghana.

Uses

The wood is used for local construction. The twigs are used as chewing sticks, and a decoction of leafy twigs is administered as a cholagogue and tonic. The leaves and ash from pods are used as a substitute for soap. Roasted seeds are reportedly edible. A vegetable salt has been obtained from wood ash by leaching.

Properties

The heartwood is reddish brown with darker streaks and distinctly demarcated from the pale yellow sapwood. The grain is interlocked; the texture fine. The wood is moderately heavy, with a density of about 770 kg/m³ at 12% moisture content, and hard. It dries quite fast and well. The recorded workability of the wood varies from fairly well to difficult. It is resistant against both fungi and insects.

Description

• Medium-sized to fairly large tree up to 35 m tall; bole often fluted and bent, up to 160 cm in diameter, with large, humped buttresses; bark brown, roughly scaly.
• Leaves alternate, clustered at the ends of twigs, bipinnately compound with a single pair of pinnae; stipules linear, persistent; petiole 1.5–5 cm long, shortly hairy, with large gland at apex on upper side; pinna axis 10–35 cm long; leaflets in 9–20 pairs per pinna, opposite, oblong-lanceolate to oblong-elliptical, up to 9 cm × 2 cm, rounded at base, acuminate at apex, shortly hairy below.
• Inflorescence an axillary head c. 2 cm in diameter, many-flowered; peduncle 3–8 cm long.
• Flowers bisexual, regular, 5-merous, small, sessile, hairy; calyx cylindrical, c. 3 mm long, shortly toothed; petals free, linear-oblong, c. 4 mm long, brownish yellow; stamens 10, free, c. 8 mm long, with glands at apex; ovary superior, c. 1 mm long, long-hairy, 1-celled, style short.
• Fruit a narrowly oblong pod up to 20 cm × 5 cm, flattened, long-attenuate at base, obtuse at apex, slightly curved, woody, brown, 2-valved, 4–9-seeded.
• Seeds obovoid-ellipsoid, c. 2 cm × 1.5 cm, flattened, glossy.
• Seedling with epigeal germination.

Other botanical information

Xylia comprises 9 species, 6 of which occur in continental Africa, 2 in Madagascar and 1 in tropical Asia. It is related to Calpocalyx, which differs in its spike-like inflorescences.

Xylia xylocarpa

Xylia xylocarpa (Roxb.) Taub. from tropical Asia is an important timber tree in Myanmar and India, and has occasionally been planted in tropical Africa. The wood is heavy, hard and durable and used for heavy construction.

Xylia hoffmannii

The wood of Xylia hoffmannii (Vatke) Drake is used for furniture in northern Madagascar; a decoction of the pods is taken as a tonic. Xylia hoffmannii is a tree up to 25 m tall, with a bole up to 40 cm in diameter, and is locally common in tall forest on limestone soils.

Young Xylia evansii trees have an annual diameter increment of 0.6–1.4 cm. Seedlings develop ectotrophic mycorrhizae. The trees are often deciduous for a short period. Flowers are produced towards the end of the dry season. The seeds are dispersed by the explosively opening pods at the end of the dry season.

Ecology

Xylia evansii occurs in evergreen forest, semi-deciduous forest and gallery forest. It is often found on well-drained alluvial soils and on hillsides with deep soils.

Management

Large trees usually occur scattered in the forest, but are locally abundant, e.g. in Sierra Leone and Ghana. In some forest areas of Sierra Leone an average density of 2.7 trees of over 70 cm bole diameter per ha has been recorded. Regeneration is in small to medium-sized forest gaps, but seedlings are usually not abundant. However, the germination rate of seeds in the nursery is fair. Germination starts 4–10 days after sowing. The 1000-seed weight is about 400 g.

Genetic resources

Xylia evansii does not seem to be in immediate danger of genetic erosion. Although it is restricted to the forest zone of West Africa, it is widespread there, and locally common.

Prospects

Little is known about Xylia evansii, and more research, especially on propagation and growth rates, is needed to evaluate its possible role in sustainably managed natural production forest in West Africa.

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.

• Holmgren, M., Poorter, L., Siepel, A., Bongers, F., Buitelaar, M., Chatelain, C., Gautier, L., Hawthorne, W.D., Helmink, A.T.F., Jongkind, C.C.H., Os-Breijer, H.J., Wieringa, J.J. & van Zoest, A.R., 2004. Ecological profiles of rare and endemic species. In: Poorter, L., Bongers, F., Kouamé, F.N’. & Hawthorne, W.D. (Editors). Biodiversity of West African forests. An ecological atlas of woody plant species. CAB International, Wallingford, United Kingdom. pp. 101–389.

• Savill, P.S. & Fox, J.E.D., 1967. Trees of Sierra Leone. Forest Department, Freetown, Sierra Leone. 316 pp.

Other references

• 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.

• de la Mensbruge, G., 1966. La germination et les plantules des essences arborées de la forêt dense humide de la Côte d’Ivoire. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 389 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.

• du Puy, D.J., Labat, J.N., Rabevohitra, R., Villiers, J.-F., Bosser, J. & Moat, J., 2002. The Leguminosae of Madagascar. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 750 pp.

• Hawthorne, W.D., 1995. Ecological profiles of Ghanaian forest trees. Tropical Forestry Papers 29. Oxford Forestry Institute, Department of Plant Sciences, University of Oxford, United Kingdom. 345 pp.

• Irvine, F.R., 1961. Woody plants of Ghana, with special reference to their uses. Oxford University Press, London, United Kingdom. 868 pp.

• Nguyen Ba, 1998. Xylia Benth. In: Sosef, M.S.M., Hong, L.T. & Prawirohatmodjo, S. (Editors). Plant Resources of South-East Asia No 5(3). Timber trees: Lesser-known timbers. Backhuys Publishers, Leiden, Netherlands. pp. 590–591.

• 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.

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., 2007. Xylia evansii Hutch. 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 18 December 2024.

• See the Prota4U database.