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Soyauxia grandifolia Gilg & Stapf

Journ. Linn. Soc., Bot. 37: 102 (1905).
Origin and geographic distribution
Soyauxia grandifolia is found in Liberia, Côte d’Ivoire and Ghana.
The wood of Soyauxia grandifolia, known as ‘abotesima’ in Ghana, is mainly used as posts for construction of huts and houses. Twigs are used as chewing-sticks for cleaning teeth.
The wood is dull purple-brown, hard, strong and flexible. It has a fine texture, is easy to work and finishes smoothly.
Small to medium-sized tree up to 25 m tall; bole usually crooked, up to 25 cm in diameter, buttresses absent; bark surface grey-brown, thin, flaking; crown spreading; twigs flat and with lenticels. Leaves arranged spirally, simple and entire; stipules paired, oblong, c. 10 mm × 2 mm; petiole short; blade oblong to lanceolate, 12–32 cm × 4–11 cm, obtuse at base, acuminate to acute at apex, leathery, almost glabrous, pinnately veined with more than 15 pairs of distinct lateral veins. Inflorescence a dense raceme 6–12 cm long. Flowers bisexual, regular, 5-merous; pedicel very short; sepals c. 5 mm long, persistent in fruit, rusty hairy; petals free, whitish; corona short, tubular; stamens many, filaments long, anthers 4-celled; ovary superior, 1-celled, styles 3, long and exserted. Fruit a sessile, 3-valved capsule up to 3 cm × 2.5 cm, red-brown to purple, 1-seeded. Seed trigonous, c. 2 cm in diameter.
Soyauxia comprises about 6 species. It has been placed in Flacourtiaceae and Passifloraceae and resembles some Euphorbiaceae. More recently it has been included in Medusandraceae, but the most modern approach is to place it in Peridiscaceae, together with 2 genera from tropical America.
Soyauxia grandifolia is found in humid, evergreen forest, sometimes in secondary forest, on river banks and in coastal savanna. It prefers regions with high annual rainfall (above 2500 mm), but can also be found in regions with a lower mean annual rainfall, from 1500 mm onwards. In Ghana it is only common on very acid soils, but elsewhere it has been recorded on sandy, loamy as well as lateritic soils.
Soyauxia grandifolia regenerates in the shade of the forest canopy.
Genetic resources and breeding
Although Soyauxia grandifolia is not widely distributed, no serious threats are envisaged.
The wood of Soyauxia grandifolia is not of interest for commercial exploitation but will continue to play a role for local uses.
Major references
• Aubréville, A., 1959. La flore forestière de la Côte d’Ivoire. Deuxième édition révisée. Tome troisième. Publication No 15. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 334 pp.
• Burkill, H.M., 1997. The useful plants of West Tropical Africa. 2nd Edition. Volume 4, Families M–R. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 969 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.
• Keay, R.W.J., 1958. Medusandraceae. 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. 652–656.
Other references
• Bancroft, H., 1935. The wood anatomy of representative members of the Monotoideae. American Journal of Botany 22(8): 717–739.
• Bayer, C., 2007. Peridiscaceae. In: Kubitzki, K. (Editor). The families and genera of vascular plants. Vol. 9. Flowering plants - Eudicots. Springer-Verlag, Berlin, Heidelberg, Germany. pp. 297–300.
• Brenan, J.P.M., 1953. Soyauxia, a second genus of Medusandraceae. Kew Bulletin 8: 507–511. • 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.
• Hawthorne, W. & Jongkind, C., 2006. Woody plants of western African forests: a guide to the forest trees, shrubs and lianes from Senegal to Ghana. Kew Publishing, Royal Botanic Gardens, Kew, United Kingdom. 1023 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.
C.H. Bosch
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

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
Associate editors
E.A. Obeng
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:
Bosch, C.H., 2010. Soyauxia grandifolia Gilg & Stapf. In: Lemmens, R.H.M.J., Louppe, D. & Oteng-Amoako, A.A. (Editors). Prota 7(2): Timbers/Bois d’œuvre 2. [CD-Rom]. PROTA, Wageningen, Netherlands.
wood in transverse section

wood in tangential section