Prota 3: Dyes and tannins/Colorants et tanins
Prodr. fl. Ind. orient. 1: 242 (1834).
Papilionaceae (Leguminosae - Papilionoideae, Fabaceae)
Flemingia rhodocarpa Baker (1871), Moghania grahamiana (Wight & Arn.) Kuntze (1891), Moghania rhodocarpa (Baker) Hauman (1954).
Origin and geographic distribution
Flemingia grahamiana is widespread in tropical Africa, from Ghana east to Ethiopia and south to South Africa, extending via Arabia to southern India. In Yemen it has been cultivated as a dye and medicinal plant since ancient times. Formerly it was also cultivated in Ethiopia and the dye was exported to Yemen.
Flemingia grahamiana is one of the principal sources of the Arab dye called ‘waras’, ‘wars’ or ‘warus’. Waras is a coarse purple or brilliant orange-brown powder, consisting of single (not grouped) hairs and dark gland globules rubbed from dry fruits. The powder is used in India, the Arab world and in Africa (e.g. in Uganda, Zimbabwe and Malawi), mainly for dyeing silk and cotton a golden-yellow, but also for other purposes such as dyeing bamboo for baskets and making coloured ink. It does not seem to be applied to wool. It is also used as a cosmetic by placing a small portion of the powder in the palm of the hand and moistening it with water; the hands are then rubbed together, producing a lather of a bright gamboge colour, which is applied as required. In DR Congo Flemingia grahamiana is recommended as a cover crop. The tuberous root is said to be edible. In Zimbabwe and Malawi a root decoction is drunk against diarrhoea and dysentery. In India the plant is used in external applications against skin diseases, internally as a purgative and as a medicine for colds.
The fruit powder of Flemingia grahamiana contains a dark red to orange-brown resin, an orange-red crystalline substance and small quantities of a yellow crystalline substance. These are flavonoid colorants belonging to the group of chalcones: flemingins A, B and C, homoflemingin and 5-deoxyhomoflemingin. These principles resemble those of kamala (Mallotus philippinensis (Lam.) Muell.Arg.), which also are complex chalcones, but not identical. The dye of kamala is also produced by the glands on the fruits and in international trade waras and kamala are often traded together. In dye powder of waras, uncoloured long and simple hairs can be found, whereas in dye powder of kamala short uncoloured stellate hairs are found.
Erect herb or subshrub up to 1.8 m tall with deep growing, sometimes tuberous roots. Leaves alternate, 3-foliolate; stipules deciduous; petiole up to 7 cm long; petiolules c. 3 mm long; leaflets elliptical to obovate, 2–15 cm × 1–8 cm, terminal leaflets largest, pubescent to densely velvety, sparsely to densely covered with small dark red glands. Inflorescence an axillary, densely fasciculate raceme; rachis 1–5 cm long, with imbricate bracts. Flowers bisexual, papilionaceous; pedicel c. 2 mm long; calyx tubular, tube c. 1.5 mm long, lobes 5, linear, 3–6 mm long; corolla yellow-white or pink, standard oblong, 7–8 mm long, wings narrow, slightly shorter than standard, keel about as long as wings; stamens 10, 9 fused and upper one free; ovary superior, hairy, 1-celled, style linear, ending in a small dot-like stigma. Fruit an inflated pod 9–12 mm × 6 mm, yellow-pubescent and also covered with glands secreting reddish globules leaving an orange-red stain on touching, 2-seeded. Seeds globose, c. 1.5 mm in diameter, shiny black.
Flemingia is classified in the tribe Phaseoleae and is predominantly an Asiatic genus comprising 30–50 species. From tropical Africa only 2 indigenous species are known. Flemingia grahamiana is very variable and based on degree of pubescence and size of leaflets and inflorescence, several varieties have been distinguished. Flemingia macrophylla (Willd.) Merr. (originating from tropical Asia) much resembles Flemingia grahamiana. It is occasionally cultivated in tropical Africa, e.g. in Côte d’Ivoire, Nigeria and Tanzania. Its fruits can produce the same type of dye (less abundantly), but it is more important as an auxiliary plant grown for shade, cover and mulch.
Flemingia grahamiana is found in open and wooded savanna, sometimes near water in riverine vegetation, on hillsides, termite mounds and along roadsides, in eastern Africa up to 2100 m altitude.
Flemingia grahamiana can be propagated by seed. The first fruits can be harvested after about one year. After picking the fruits, the shrub is cut down at about 15 cm from ground level. It sprouts again after rain and bears fruits a second time after about six months. The cutting back is repeated every second year until the plant dies. Rain destroys the fruits for commercial purposes; therefore they are only gathered in the dry season. The harvested fruits are first dried (some days in the sun), put in a bag, which then is beaten to loosen the tinctorial powder. Alternatively the fruits are rubbed over a sieve. To prepare the dye, the powder is dissolved in the dye bath with an equal weight of sodium carbonate. When the temperature of the bath reaches 40°C the yarns or textiles to be dyed are put into the bath and the whole is slowly heated to boiling point. To make the colour brighter, the fibre can be washed in slightly acidic water, e.g. made with lemon juice. Beautiful deep yellow or orange colours can be obtained, fast to light and acids, less so to alkaline substances. Those colours were used very frequently in combination with indigo blue in the renowned ikat textiles from Yemen.
Genetic resources and breeding
Flemingia grahamiana is widely distributed and not in danger of genetic erosion. Germplasm collections are maintained at the Centro Internacional de Agricultura Tropical (CIAT, Cali, Colombia), the Research Institute for Animal Production (Ciawi, Bogor, Indonesia), Australian Tropical Forage Genetic Resource Centre (ATFGRC, CSIRO, Canberra, Australia), and the International Plant Genetic Resources Institute (IPGRI, Bangkok, Thailand), together with those of Flemingia macrophylla.
As source of the waras dye, Flemingia grahamiana will remain only locally of importance for dyeing textiles golden-orange or colouring wickerwork. In the current light of the reappraisal of European regulations concerning the toxicity of some synthetic colorants used in the food and cosmetic industries, the traditional applications of waras as a cosmetic and against skin diseases could make it a suitable substitute as a yellow to orange colorant. Its value as a cover crop and as a medicine need more investigation.
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Correct citation of this article:
Jansen, P.C.M., 2005. Flemingia grahamiana Wight & Arn. In: Jansen, P.C.M. & Cardon, D. (Editors). PROTA 3: Dyes and tannins/Colorants et tanins. [CD-Rom]. PROTA, Wageningen, Netherlands.