Prota 7(2): Timbers/Bois d’œuvre 2
Schumach., Beskr. Guin. pl.: 129 (1827).
Origin and geographic distribution
Ehretia cymosa is very widespread, from Sierra Leone east to Ethiopia and Kenya, and south to Zimbabwe and Mozambique; also in Comoros, Mayotte and Madagascar.
The wood is used for furniture, cabinet work, poles, tool handles and yokes. It is also used as firewood and for making charcoal.
The twigs serve as chewing-sticks for maintaining tooth and gum hygiene. Many plant parts are used in traditional medicine. A leaf infusion is taken and used as a wash to treat fever and convulsions. Leaf sap is reportedly a mild laxative and is applied as a haemostatic. Leaf decoctions serve as a treatment for stiffness, toothache and hyperthermia. In Ghana leaf poultices are applied to fractured bones to promote healing. Leafy twigs are used in mixtures with parts of other plants to treat gastric ulcers. Root and leaf decoctions are administered to treat tetanus and dysentery. Roots and leaves are considered to be aphrodisiac. Bark and root decoctions are taken as a treatment for menstruation problems, and a bark decoction is applied externally against skin diseases. The Maasai people use the roots to treat brucellosis. In Ethiopia crushed roots in water are taken against stomach complaints. Root juice is applied to wounds.
The leaves serve as fodder. Ehretia cymosa is locally important as livestock feed in agroforestry systems in Ethiopia. The leaves make a good mulch. The fruits are edible. The flowers are a source of nectar and pollen for honey bees. Ehretia cymosa is planted as an ornamental tree, e.g. in Kenya and Uganda.
The wood is greyish brown with alternate darker and lighter bands, and lustrous. The texture is moderately fine and even. The wood is moderately lightweight, with a density of 480–550 kg/m³ at 12% moisture content, and not durable.
In an in-vitro test utilizing rat calvarial bone, aqueous leaf extracts showed stimulation of bone remodelling. Roots and leaves are reportedly toxic, but livestock browse on the leaves apparently without adverse effects. Analyses of the leaves even showed good nutritional values for ruminants, except the micronutrient levels of Na and Cu.
Deciduous shrub or small to medium-sized tree up to 20(–25) m tall; bole often low branching and crooked, up to 30 cm in diameter; bark surface grey to pale brown, with prominent lenticels, inner bark soft, white, spotted with orange-brown, quickly turning brown upon exposure; crown spreading, often with drooping branches; twigs short-hairy but soon becoming glabrous. Leaves arranged spirally, simple and entire; stipules absent; petiole 1–3.5 cm long, slightly grooved; blade elliptical to ovate-oblong, (4–)7.5–20 cm × (2–)3.5–12 cm, cuneate to rounded or slightly cordate at base, acuminate at apex, thinly leathery, nearly glabrous, pinnately veined with 3–8 pairs of lateral veins. Inflorescence an axillary or terminal, strongly branched panicle up to 15 cm × 15 cm, composed of scorpioid cymes, hairy. Flowers bisexual, regular, usually 5-merous, heterostylous, fragrant; pedicel up to 2(–3) mm long, jointed at base; calyx campanulate, 1.5–2.5 mm long, lobes about as long as tube; corolla campanulate, 4–8 mm long, white to yellowish or pinkish white, lobes about as long as tube, often reflexed; stamens inserted at corolla, exserted; ovary superior, ovoid, c. 1 mm long, 2- or 4-celled, style 1–4 mm long, 2-branched at apex. Fruit an ovoid to globose drupe 2–6 mm long, orange to red and eventually turning black, splitting into 4 pyrenes, each 1-seeded.
Some varieties have been distinguished within Ehretia cymosa, based on flower size and hairiness of the inflorescence, but there is some disagreement about the usefulness of this division.
Ehretia cymosa grows rapidly. The flowers are commonly visited by bees, which collect nectar and pollen and may serve as pollinator. In Côte d’Ivoire trees flower from January to June. In East and southern Africa fruits mature in October–December. The fruits are eaten by birds, which may disperse the seeds.
Ehretia comprises about 35 species, most of them in tropical Asia (about 20), about 10 in mainland Africa, 7 in Comoros and Madagascar (5 endemic) and 3 in tropical America. The wood of several Ehretia spp. is used in tropical Africa in similar ways as that of Ehretia cymosa.
Ehretia amoena Klotzsch is a shrub or small tree up to 8 m tall, found from Kenya south to South Africa. It has been much confused with Ehretia obtusifolia A.DC., and care is needed to interpret the literature. Its wood is used for implements and kitchen tools, e.g. pestles. Root decoctions are used in traditional medicine to treat pain, bleedings, swellings, pneumonia, tuberculosis, gonorrhoea, epilepsy, vomiting, diarrhoea, hookworm infections and menstruation problems. Bark powder is administered to skin diseases. Leaf pulp is applied to wounds.
Ehretia rigida (Thunb.) Druce is a shrub or small tree up to 6(–12) m tall, occurring in savanna woodland from Zimbabwe and Mozambique to South Africa. It closely resembles Ehretia amoena and Ehretia obtusifolia. Its tough and flexible wood is probably used in the same way as that of the 2 latter species. Root powder is externally applied to wounds and burns, and to treat pain. Root decoctions are taken to treat menstruation problems and infertility. Ehretia rigida is commonly browsed by livestock.
Ehretia trachyphylla C.H.Wright is a small to medium-sized tree up to 20 m tall and bole up to 30 cm in diameter, occurring in evergreen and riverine forest in Côte d’Ivoire and Ghana. Its speckled wood is used for tool handles. Bark decoctions are used in traditional medicine in the same way as those of Ehretia cymosa, to treat menstruation problems and skin diseases.
Ehretia cymosa has a wide ecological range, occurring in the understorey or at edges of evergreen forest and in riverine forest, forest patches, bushland and wooded savanna, up to 2400 m altitude. It is classified as a pioneer and often found in secondary forest.
One kg contains 20,000–30,000 seeds. Whole infructescences are usually harvested when about 80% of the fruits have become ripe. Seeds are extracted and usually sown directly into the field. Pre-treatment of the seed is unnecessary. Seeds may start germinating already after 3 days, but germination may continue for 5 weeks. The seeds can be stored for some time.
Locally Ehretia cymosa is quite common, e.g. in forest on Mount Elgon in Kenya an average density of 15 boles with a diameter of more than 15 cm per ha has been recorded. Trees can be managed by pruning, pollarding, lopping and coppicing.
Genetic resources and breeding
Ehretia cymosa is not threatened, being very widely distributed and adapted to a wide variety of habitats. Locally it seems to be threatened by over-exploitation, e.g. in northern Tanzania.
Ehretia cymosa is highly valued as a multipurpose tree, yielding timber, firewood and forage, whereas it is considered important for traditional medicine and mulch, and as ornamental and bee plant. It is certainly of great value for agroforestry systems, and more research on propagation techniques and planting is justified, as well as on phytochemistry and pharmacological activities. The often poor shape of the bole is a serious drawback for increased commercial exploitation of the timber.
• Bekele-Tesemma, A., 2007. Useful trees and shrubs for Ethiopia: identification, propagation and management for 17 agroclimatic zones. Technical Manual No 6. RELMA in ICRAF Project, Nairobi, Kenya. 552 pp.
• Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 960 pp.
• Lewis, W.H. & Avioli, L.V., 1991. Leaves of Ehretia cymosa (Boraginaceae) used to heal fractures in Ghana increase bone remodeling. Economic Botany 45(2): 281–282.
• Maundu, P. & Tengnäs, B. (Editors), 2005. Useful trees and shrubs for Kenya. World Agroforestry Centre - East and Central Africa Regional Programme (ICRAF-ECA), Technical Handbook 35, Nairobi, Kenya. 484 pp.
• Verdcourt, B., 1991. Boraginaceae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 125 pp.
• Beentje, H.J., 1994. Kenya trees, shrubs and lianas. National Museums of Kenya, Nairobi, Kenya. 722 pp.
• Coates Palgrave, K., 1983. Trees of southern Africa. 2nd Edition. Struik Publishers, Cape Town, South Africa. 959 pp.
• Latham, P., 2007. Plants visited by bees and other useful plants of Umalila, southern Tanzania. Third edition. P.Latham, DFID, United Kingdom. 216 pp.
• Mamo, Y., 1997. Current role and the potential of three indigenous tree species of Ethiopia: Ehretia cymosa, Vernonia amygdalina and Faidherbia albida, as feed for livestock under traditional agroforestry practices. MSc thesis, Swedish University of Agricultural Sciences, Uppsala, Sweden. 53 pp.
• Martins, E.S. & Brummitt, R.K., 1990. Boraginaceae. In: Launert, E. & Pope, G.V. (Editors). Flora Zambesiaca. Volume 7, part 4. Flora Zambesiaca Managing Committee, London, United Kingdom. pp. 59–110.
• Maundu, P., Berger, D., Saitabau, C., Nasieku, J., Kipelian, M., Mathenge, S., Morimoto, Y. & Höft, R., 2001. Ethnobotany of the Loita Maasai. Towards community management of the forest of the Lost Child. Experiences from the Loita Ethnobotany Project. UNESCO People and Plants Working Paper 8, Paris, France. 34 pp.
• Miller, J.S., 2002. A revision of Ehretia (Boraginaceae) for Madagascar and the Comoro Islands. Adansonia 24(2): 137–157.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Retief, E. & van Wyk, A.E., 2001. The genus Ehretia (Boraginaceae: Ehretioideae) in southern Africa. Bothalia 31(1): 9–23.
• Wondimu, T., Asfaw, Z. & Kelbessa, E., 2007. Ethnobotanical study of medicinal plants around ‘Dheeraa’ town, Arsi Zone, Ethiopia. Journal of Ethnopharmacology 112: 152–161.
Correct citation of this article:
Lemmens, R.H.M.J., 2009. Ehretia cymosa Thonn. 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.