Prota 3: Dyes and tannins/Colorants et tanins
Ann. Sci. Nat., Bot., ser. 2, 13: 271 (1840).
Origin and geographic distribution
Acridocarpus excelsus is endemic to Madagascar, where it is widespread.
The bark of Acridocarpus excelsus is collected from the wild, pounded fresh or dried and boiled for 2–3 hours. The decoction can be used to dye fibres deep red by simple immersion. The fibres can also be mordanted afterwards by steeping them in a solution of tamarind (Tamarindus indica L.) ash, which produces a fast red-brown. A decoction of the bark is used against diarrhoea and dysentery.
The bark of Acridocarpus excelsus is rich in tannin and has astringent properties. The wood is red and hard.
Deciduous shrub or small tree up to 15 m tall, with thick, grey, roughly fissured bark. Leaves opposite or alternate, grouped at the end of branches, simple and entire; stipules absent; petiole up to 1.5 cm long; blade lanceolate to obovate or elliptical, up to 8 cm × 3.5 cm, leathery, often silky pubescent below, pinnately veined with lateral veins in 7–12 pairs. Inflorescence a terminal raceme 2–7 cm long, 8–15-flowered. Flowers bisexual, zygomorphic, 5-merous; pedicel 1–2 cm long; sepals ovate-elliptical, up to 3.5 mm × 2 mm; petals unequal, elliptical, 6–11 mm × 5–7 mm, clawed, more or less curled and concave, margins fimbriate, yellow; stamens 10, unequal, filaments up to 2.5 mm long; ovary superior, globose, 3-celled, styles 2, up to 5 mm long. Fruit a samara up to 3 cm × 1.5 cm.
Acridocarpus comprises about 30 species, distributed in mainland Africa (23 species), Madagascar (4 species), the Arabian Peninsula, India and New Caledonia (each 1 species). Mainly based on differences in fruit and leaf characters, Acridocarpus excelsus has been subdivided into 4 subspecies, some with several varieties. It has the habit of an olive tree and is somewhat fire resistant. Most Acridocarpus species with a thick and tannin-rich bark are used against diarrhoea.
Acridocarpus excelsus occurs from humid littoral forest to dry deciduous forest and thickets. It is usually found on dry, rocky and sandy soils, from sea-level up to 1250 m altitude.
Genetic resources and breeding
Acridocarpus excelsus is widespread in Madagascar and does not seem to be in danger of genetic erosion.
Acridocarpus excelsus as a source of red dye will remain only of some importance locally. However, the use of natural dyes in Madagascar is being revived to produce traditional textiles for the international market.
• Arènes, J., 1950. Malpighiacées (Malpighiaceae). Flore de Madagascar et des Comores (plantes vasculaires), famille 108. Firmin-Didot et cie., Paris, France. 183 pp.
• Decary, R., 1946. Plantes et animaux utiles de Madagascar. Annales du Musée Colonial de Marseille, 54e année, 6e série, 4e volume, 1er et dernier fascicule. 234 pp.
• Etheve, A.-M., 2005. Teintures naturelles à Madagascar. CITE, Antananarivo, Madagascar. 40 pp.
• Schatz, G.E., 2001. Generic tree flora of Madagascar. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 477 pp.
Correct citation of this article:
Jansen, P.C.M., 2005. Acridocarpus excelsus A.Juss. In: Jansen, P.C.M. & Cardon, D. (Editors). PROTA 3: Dyes and tannins/Colorants et tanins. [CD-Rom]. PROTA, Wageningen, Netherlands.