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Persicaria decipiens (R.Br.) K.L.Wilson

Telopea 3: 178 (1988).
Polygonum salicifolium Brouss. ex Willd. (1809), Polygonum decipiens R.Br. (1810), Polygonum serrulatum Lag. (1816), Persicaria salicifolia (Brouss. ex Willd.) Assenov (1966) non S.F.Gray.
Vernacular names
Willow weed, slender knotweed, snake root (En). Renouée à feuilles de saule (Fr).
Origin and geographic distribution
Persicaria decipiens is widespread from the Mediterranean region to southern Africa, also in South-East Asia and Australia. It has become widely naturalized elsewhere (e.g. in Madagascar).
In Africa and elsewhere, the leaves of Persicaria decipiens are locally eaten as a cooked vegetable, but usually considered a famine food. In DR Congo the plant is burnt to obtain vegetable salt. In Tanzania the leaves are used medicinally as a purgative, in Guinea they are applied to syphilitic sores; in southern Africa a leaf paste is applied to sores.
Leaves of Persicaria decipiens contain per 100 g: water 80.0 g, energy 268 kJ (64 kcal), protein 3.6 g, fat 0.3 g, carbohydrate 14.7 g, fibre 3.5 g, Ca 150 mg, P 46 mg (Leung, W.-T.W., Busson, F. & Jardin, C., 1968). Cooked leaves are slimy, coarse and not very popular.
Erect or basally decumbent, slender annual herb up to 1 m tall, with simple or branched, glabrous stem, rooting at lower nodes. Leaves alternate, simple, subsessile; ocrea cylindrical, up to 2 cm long, thinly covered with bristly hairs and terminally fringed with stiff bristles up to 2.5 cm long; blade lanceolate-elliptical, 8–15 cm × 1–2 cm, base attenuate, apex acute, margins ciliate. Inflorescence a slender, spike-like raceme 2–9 cm long, often 2–7 together to appear somewhat digitate and zigzag when young; bracts red-brown, with a terminal fringe of rigid bristles. Flowers bisexual, heterostylous; perianth 2–3 mm long, 5-lobed with broadly ovate lobes, pink or white; stamens 7–8; ovary superior, 1-celled, styles 3, united in lower half, stigmas orange. Fruit a trigonous or lens-shaped nut up to 2.5 mm long, shiny black.
The taxonomy of Persicaria has not yet stabilized, at present comprising about 150 species. Most species have been described in the genus Polygonum, from which Persicaria is a segregate.
Persicaria decipiens grows in damp localities, often in water, from sea-level up to 2400 m altitude. Locally it may be troublesome because of its invasive nature.
Persicaria decipiens is only collected from the wild and not cultivated.
Genetic resources and breeding
Persicaria decipiens is widespread and not in danger of genetic erosion.
Persicaria decipiens will remain locally a famine food always available from the wild. Its medicinal properties need more research.
Major references
• Burkill, H.M., 1997. The useful plants of West Tropical Africa. 2nd Edition. Volume 4, Families M–R. Royal Botanic Gardens, Kew, United Kingdom. 969 pp.
• Katende, A.B., Ssegawa, P. & Birnie, A., 1999. Wild food plants and mushrooms of Uganda. Technical Handbook No 19. Regional Land Management Unit/SIDA, Nairobi, Kenya. 490 pp.
• Kokwaro, J.O., 1993. Medicinal plants of East Africa. 2nd Edition. Kenya Literature Bureau, Nairobi, Kenya. 401 pp.
• Ruffo, C.K., Birnie, A. & Tengnäs, B., 2002. Edible wild plants of Tanzania. Technical Handbook No 27. Regional Land Management Unit/ SIDA, Nairobi, Kenya. 766 pp.
• Tredgold, M.H., 1986. Food plants of Zimbabwe. Mambo Press, Gweru, Zimbabwe.153 pp.
Other references
• Cavaco, A., 1953. Polygonacées (Polygonaceae). Flore de Madagascar et des Comores (plantes vasculaires), famille 65. Firmin-Didot et cie., Paris, France. 22 pp.
• Graham, R.A., 1958. Polygonaceae. In: Turrill, W.B. & Milne-Redhead, E. (Editors). Flora of Tropical East Africa. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. 40 pp.
• Hedberg, O., 2000. Polygonaceae. In: Edwards, S., Mesfin Tadesse, Demissew Sebsebe & Hedberg, I. (Editors). Flora of Ethiopia and Eritrea. Volume 2, part 1. Magnoliaceae to Flacourtiaceae. The National Herbarium, Addis Ababa University, Addis Ababa, Ethiopia and Department of Systematic Botany, Uppsala University, Uppsala, Sweden. pp. 336–347.
• Leung, W.-T.W., Busson, F. & Jardin, C., 1968. Food composition table for use in Africa. FAO, Rome, Italy. 306 pp.
• Nguyen Thi Do, 2001. Persicaria Miller. In: van Valkenburg, J.L.C.H. & Bunyapraphatsara, N. (Editors). Plant Resources of South-East Asia No 12(2): Medicinal and poisonous plants 2. Backhuys Publishers, Leiden, Netherlands. pp. 412–415.
• Petit, E., 1958. Polygonaceae. In: Extrait de Flore du Congo, du Ruanda et du Burundi. Spermatophytes. Volume 7. Jardin botanique national de Belgique, Brussels, Belgium. pp. 238–286.
• Thulin, M., 1993. Polygonaceae. In: Thulin, M. (Editor). Flora of Somalia. Volume 1. Pteridophyta; Gymnospermae; Angiospermae (Annonaceae-Fabaceae). Royal Botanic Gardens, Kew, United Kingdom. pp. 175–179.
• van den Bergh, M.H., 1993. Minor vegetables. In: Siemonsma, J.S. & Kasem Piluek (Editors). Plant Resources of South-East Asia No 8. Vegetables. Pudoc Scientific Publishers, Wageningen, Netherlands. pp. 280–310.
• Williamson, J., 1955. Useful plants of Nyasaland. The Government Printer, Zomba, Nyasaland. 168 pp. (Reprint: Williamson, J., 1975. Useful plants of Malawi. University of Malawi, Zomba, Malawi).
• Wilson, K.L., 1990. Some widespread species of Persicaria (Polygonaceae) and their allies. Kew Bulletin 45(4): 621–636.
P.C.M. Jansen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

G.J.H. Grubben
Prins Hendriklaan 24, 1401 AT Bussum, Netherlands
O.A. Denton
National Horticultural Research Institute, P.M.B. 5432, Idi-Ishin, Ibadan, Nigeria
Associate Editors
C.-M. Messiaen
Bat. B 3, Résidence La Guirlande, 75, rue de Fontcarrade, 34070 Montpellier, France
R.R. Schippers
De Boeier 7, 3742 GD Baarn, Netherlands
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., 2004. Persicaria decipiens (R.Br.) K.L.Wilson In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.