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Pterolobium stellatum (Forssk.) Brenan

Protologue
Mem. New York Bot. Gard. 8: 425 (1954).
Family
Caesalpiniaceae (Leguminosae - Caesalpinioideae)
Vernacular names
Kantuffa, redwing (En). Mutanda (Sw).
Origin and geographic distribution
Pterolobium stellatum is widespread in Africa, where it is found from Sudan and Eritrea southwards throughout Central, East and southern Africa to South Africa, but not in Angola, Namibia and Botswana. It also occurs in Yemen.
Uses
In Ethiopia, since historical times, the infusion of the pounded bark of Pterolobium stellatum, has been a major ingredient for tanning Morocco leather at the same time giving it a bright red colour. It is already mentioned by European travellers in the 19th century. The crushed leaves also yield a dark red dye for leather; ground and boiled in water to which a little oil or butter has been added to help fix the colour, they are also used to dye clothes for mourning, for dark colours in basketry and to colour mats made from doum palm (Hyphaene thebaica (L.) Mart.) leaves. Formerly the leaves were one of the main ingredients for making black ink, based on the chemical reaction of the tannins of the plant with iron slag or iron filings from the blacksmith. This ink is water resistant and was used by the famous plant collector G.W. Schimper around 1840 to write the labels of his Ethiopian plants. Leather is dyed black by treatment with a mixture of dried leaves and iron filings (iron-oxide) in water.
Pterolobium stellatum is also used for firewood and fodder, and as live fence and ornamental. Because of the sharp, recurved prickles, branches are used to make rat traps. Pterolobium stellatum is sometimes planted to combat the weedy cactus Opuntia. In traditional medicine in East Africa, fresh leaves are chewed or a decoction is drunk to treat tuberculosis and related respiratory diseases. In Kenya a root decoction is used by the Maasai against stomach-ache. Juice of the roots is swallowed to treat snakebites. In Malawi a root infusion is drunk by women against infertility.
Properties
The leaves of Pterolobium stellatum contain approximately 20% tannin. Neither the tannins of bark and leaves nor their dye content appear to have been investigated and characterized.
Botany
Climbing or straggling shrub, with stems up to 15 m long, armed with recurved prickles. Leaves alternate, with small, early caducous stipules, bipinnately compound with 5–13 pairs of pinnae; rachis armed with paired recurved prickles and often also solitary straight ones; leaflets 7–16 pairs per pinna, oblong or elliptical-oblong, 4–12 mm × 2–5 mm, pubescent to glabrous. Inflorescence a dense raceme 5–18 cm long, aggregated into extensive terminal panicles up to 35 cm × 20 cm. Flowers bisexual, slightly zygomorphic, 5-merous, small, sweetly scented, pale yellow or whitish; pedicel 3–6 mm long; sepals 2–3 mm long, unequal, the lower one hood-shaped and embracing the others, pale green; petals almost equal, oblanceolate-oblong, c. 3 mm × 1.5 mm, pubescent towards base; stamens 10, filaments alternately longer and shorter, 4–5 mm long, pubescent below; ovary superior, 1-celled, style gradually enlarged near apex, stigma transverse. Fruit a brick-red to scarlet, ultimately brown, winged pod, with a stalked, 1-seeded basal portion 3–6 cm long and a much prolonged upper suture broadly winged on its lower side; wing 2–4.5 cm × 1–1.5 cm. Seed ovoid-ellipsoid, c. 11 mm × 6.5 mm, olive-green.
Pterolobium belongs to the tribe Caesalpinieae and comprises about 10 species, 9 occurring in Asia and only a single one in Africa.
Ecology
Pterolobium stellatum is a common shrub, forming thickets in margins and clearings of upland dry evergreen forest, Acacia woodland and riparian formations, mainly at 500–2500 m altitude.
Management
The leaves are mostly collected from the wild, but Pterolobium stellatum is also cultivated and then propagated by seed, cuttings or wildlings. The seeds germinate better when they are scarified mechanically or chemically. They are sensitive to high temperatures, so hot water treatment before germination is not recommended. The seeds can be easily stored in airtight containers for more than a year without loss of viability. Hedges of Pterolobium stellatum plants are impenetrable because of the sharp prickles and can be pruned to a desired height and width.
Genetic resources and breeding
Pterolobium stellatum is widespread and common in many regions, and not in danger of genetic erosion. Germplasm collections are not known to exist, although some companies offer seeds for sale.
Prospects
Pterolobium stellatum being a widespread multipurpose plant, interesting both as ornamental bush and as impenetrable live fence, could represent a good renewable source of red dye that does not need a mordanting process due to the associated action of tannins. Its medicinal properties are in need of investigation.
Major references
• Bein, E., Habte, B., Jaber, A., Birnie, A. & Tengnäs, B., 1996. Useful trees and shrubs in Eritrea: identification, propagation and management for agricultural and pastoral communities. Technical Handbook No 12. Regional Soil Conservation Unit, Nairobi, Kenya. 422 pp.
• Brenan, J.P.M., 1967. Leguminosae, subfamily Caesalpinioideae. In: Milne-Redhead, E. & Polhill, R.M. (Editors). Flora of Tropical East Africa. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. 230 pp.
• Gelfand, M., Mavi, S., Drummond, R.B. & Ndemera, B., 1985. The traditional medical practitioner in Zimbabwe: his principles of practice and pharmacopoeia. Mambo Press, Gweru, Zimbabwe. 411 pp.
• Roti-Michelozzi, G., 1957. Adumbratio florae Aethiopicae 6. Caesalpiniaceae (excl. gen. Cassia). Webbia 13: 133–228.
• Tournerie, P.J.M., 1986. Colour and dye recipes of Ethiopia. Published by the author, Exeter, United Kingdom. 152 pp.
Other references
• Beentje, H.J., 1994. Kenya trees, shrubs and lianas. National Museums of Kenya, Nairobi, Kenya. 722 pp.
• Getahun, A., 1976. Some common medicinal and poisonous plants used in Ethiopian folk medecine. Faculty of Science, Addis Abeba University, Addis Abeba, Ethiopia. 63 pp.
• Jansen, P.C.M., 1981. Spices, condiments and medicinal plants in Ethiopia, their taxonomy and agricultural significance. Agricultural Research Reports 906. Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands. 327 pp.
• Kokwaro, J.O., 1993. Medicinal plants of East Africa. 2nd Edition. Kenya Literature Bureau, Nairobi, Kenya. 401 pp.
• Teketay, D., 1998. Germination of Acacia origena, A. pilispina and Pterolobium stellatum in response to different pre-sowing seed treatments, temperature and light. Journal of Arid Environments 38(4): 551–560.
• Thulin, M., 1989. Fabaceae (Leguminosae). In: Hedberg, I. & Edwards, S. (Editors). Flora of Ethiopia. Volume 3. Pittosporaceae to Araliaceae. The National Herbarium, Addis Ababa University, Addis Ababa, Ethiopia and Department of Systematic Botany, Uppsala University, Uppsala, Sweden. pp. 49–251.
• Vidal, J.E. & Hul Thol, S., 1974. Révision de genre Pterolobium (Caesalpiniaceae). Bulletin du Muséum National d’Histoire Naturelle, 3e série, 227, Botanique 15: 1 –29.
• Wilczek, R., Léonard, J., Hauman, L., Hoyle, A.C., Steyaert, R., Gilbert, G. & Boutique, R., 1952. Caesalpiniaceae. In: Robyns, W., Staner, P., Demaret, F., Germain, R., Gilbert, G., Hauman, L., Homès, M., Jurion, F., Lebrun, J., Vanden Abeele, M. & Boutique, R. (Editors). Flore du Congo belge et du Ruanda-Urundi. Spermatophytes. Volume 3. Institut National pour l’Étude Agronomique du Congo belge, Brussels, Belgium. pp. 234–554.
Author(s)
P.C.M. Jansen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands


Editors
P.C.M. Jansen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
D. Cardon
CNRS, CIHAM-UMR 5648, 18, quai Claude-Bernard, 69365 Lyon, Cedex 07, France
General editors
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article:
Jansen, P.C.M., 2005. Pterolobium stellatum (Forssk.) Brenan In: Jansen, P.C.M. & Cardon, D. (Editors). PROTA 3: Dyes and tannins/Colorants et tanins. [CD-Rom]. PROTA, Wageningen, Netherlands.