Millettia rhodantha (PROTA)
Millettia rhodantha Baill.
- Protologue: Adansonia 6: 223 (1866).
- Family: Papilionaceae (Leguminosae - Papilionoideae, Fabaceae)
- Chromosome number: 2n = 24
Origin and geographic distribution
Millettia rhodantha occurs in the forest zone from Guinea to Ghana.
The flexible branches are used in hut building. The bark is chewed to treat cough and a root decoction is taken against stomach-ache.
The wood is yellowish, hard and aromatic.
- Small tree up to 12 m tall; bole often sinuous and low-branched, up to 30 cm in diameter; bark surface grey, with lenticels, inner bark yellowish, with reddish exudate; branches sinuous, with lenticels.
- Leaves alternate, imparipinnately compound with 3–6 pairs of leaflets; stipules narrowly triangular, 3–4 mm long; petiole and rachis short-hairy; stipels threadlike, 1–2 mm long; petiolules 2–3 mm long; leaflets opposite, ovate to obovate or elliptical, 3–10 cm × 1.5–4.5 cm, acuminate at apex, short-hairy below.
- Inflorescence a false raceme up to 25 cm long, not branched, densely hairy.
- Flowers bisexual, papilionaceous; pedicel 4–6 mm long, with 2 small bracteoles near apex; calyx campanulate, 3–4 mm long, hairy, tube longer than lobes; corolla pale purple, standard orbicular, 8–10 mm in diameter, glabrous, wings and keel about as long as standard; stamens 10, 9 fused, 1 almost free; ovary superior, hairy, style slender, curved, glabrous.
- Fruit an ellipsoid, flat pod 8–12 cm × 1.5–3 cm, with short beak at apex, glabrous, yellowish, dehiscent with 2 recurving valves, 1–2-seeded.
- Seeds almost orbicular, flattened, c. 1 cm in diameter.
Other botanical information
In Côte d’Ivoire trees flower in August–September. The flowers are sweet-scented and are much visited by bees, which are probably responsible for pollination. In Ghana seeds are produced throughout the year. The roots have nodules containing nitrogen-fixing Bradyrhizobium bacteria.
Millettia comprises about 150 species, most of them (about 90) in mainland Africa, 8 endemic to Madagascar, and about 50 in tropical Asia. It is in need of revision and should be split into several genera based on molecular evidence.
Some other West African Millettia species supply timber for local use.
The flexible branches of Millettia chrysophylla Dunn, a liana, shrub or small tree up to 15 m tall occurring from Guinea to Gabon, are used for hut building in the same way as those of Millettia rhodantha.
This is also the case for Millettia lane-poolei Dunn, a small understorey tree up to 15 m tall occurring from Sierra Leone to Côte d’Ivoire, of which the wood is additionally used for handles and implements. The twigs reportedly purify water.
The branches of Millettia pallens Stapf, a light-demanding shrub or small tree up to 5 m tall occurring from Guinea to Côte d’Ivoire, are also used for hut building and implements, and they serve as chewing sticks. The inner bark is chewed to treat cough. Millettia pallens is planted in hedges.
Millettia rhodantha occurs in different types of lowland forest, including secondary forest, often along streams.
Millettia rhodantha is tolerant of shade. Seedlings may be found in the shade, but regeneration is probably most abundant in small gaps in the forest. Seeds germinate 2 weeks after sowing. In experiments in Côte d’Ivoire, inoculation with Bradyrhizobium bacteria 1 month after sowing had a positive effect on plant height and stem diameter measured at 4 and 11 months after inoculation. At 11 months after inoculation, inoculated seedlings were 60 cm tall, uninoculated ones only 30 cm.
Millettia rhodantha has a fairly wide distribution and is locally common, e.g. in Ghana, and does not seem to be under threat of genetic erosion, also because it occurs in a variety of forest types including disturbed forest.
Millettia rhodantha will remain of local importance for its wood, but is not of interest to the international market because of its small tree size.
- 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.
- 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 Koning, J., 1983. La forêt de Banco. Part 2: La Flore. Mededelingen Landbouwhogeschool Wageningen 83–1. Wageningen, Netherlands. 921 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.
- Diabate, M., Munive, A., Miana de Faria, S., Ba, A., Dreyfus, B. & Galiana, A., 2005. Occurrence of nodulation in unexplored leguminous trees native to the West African tropical rainforest and inoculation response of native species useful in reforestation. New Phytologist 166(1): 231–239.
- 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.
- Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
- Savill, P.S. & Fox, J.E.D., 1967. Trees of Sierra Leone. Forest Department, Freetown, Sierra Leone. 316 pp.
- 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. Millettia rhodantha Baill. 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 14 November 2018.
- See the Prota4U database.