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Raphia hookeri G.Mann & H.Wendl.

Protologue
Trans. Linn. Soc. 24: 438 (1864).
Family
Arecaceae (Palmae)
Chromosome number
2n = 28
Synonyms
Raphia gigantea A.Chev. (1932), Raphia sassandrensis A.Chev. (1932).
Vernacular names
Raphia palm, wine palm, Ivory Coast raphia palm (En). Raphia (Fr). Réfia (Po). Mwale (Sw).
Origin and geographic distribution
Raphia hookeri is found from Gambia through the Guinea forest zone of West Africa to Cameroon, Gabon and Congo and possibly to Angola. It is occasionally cultivated, e.g. in Nigeria. Outside Africa it is grown in India, Peninsular Malaysia and Singapore.
Uses
Raphia hookeri yields two valuable types of fibre: piassava or bass, and raffia. The very strong piassava fibre is obtained from the petiole and leaf sheath and is used locally to make weather-resistant coarse ropes, belts for climbing oil-palms and brushes. It is exported for the production of hard brooms and brushes. Piassava fibre is used to make exceptionally strong paper. It can also be used to produce very fine-textured charcoal, much favoured for the manufacture of home-made gunpowder. The soft but strong raffia fibre has also been considered a potential source of pulp for paper production. It is obtained by pulling off ribbon-like strips from the upper surface of the leaflets of young unfolding leaves and is used to make mats, hats, baskets, bags, ropes, hammocks, ceremonial costumes, etc. It may be woven into cloth. In Europe it is used as tying material for horticulture and handicrafts. The leaves of Raphia hookeri, often split lengthwise, are used for thatching, though they last only 1 year. They are also used to make mats, baskets and other articles of wickerwork, and are used for hut-walls and fences. The midribs and petioles of the leaves (‘raffia bamboo’ or ‘bamboo’) are used for poles, rafters, ladders, furniture and cross-bearers in canoes. Split lengthwise they are used to make screens.
Sap tapped from the stem when the tree nears the flowering stage ferments rapidly into palm wine (‘mimbo’), a very popular drink throughout West Africa. In Nigeria it is bottled for commercial purposes, although there is a risk that bottles can explode due to continuing fermentation. The wine is distilled into a strong alcoholic liquor and can also be used as bakers' yeast. The young terminal bud or ‘palm cabbage’ is eaten as a vegetable.
The raw fruit is poisonous and is crushed for use as fish poison. Boiled fruits are eaten in Nigeria. The oily mesocarp is used in traditional medicine for its laxative and stomachic properties and as a liniment for pains. Boiled or roasted kernels are sometimes eaten. Larvae of the rhinoceros beetle (Oryctes sp.), found in rotting stems, are collected and eaten.
Production and international trade
Raphia hookeri is the main piassava yielding Raphia species. Its piassava has been exported to temperate countries (mainly Europe) for the production of brooms and brushes since the end of the 19th Century, when the supply of South American piassava (from Attalea funifera Mart. and Leopoldinia piassaba Wallace), used in Europe for brooms since the middle of the 19th Century, could no longer meet demand. The trade reached its peak in the 1950s and 1960s (7000 t exported from Sierra Leone, the main exporting country, in 1964; 5300 t from Nigeria in 1966; there was also trade from Guinea), after which it declined with the advent of plastic brooms. The particular qualities of African piassava for broom-making are such that it still enters the international market. The main types of African piassava fibre in trade are ‘Sherbro’, ‘Sulima’ and ‘Calabar’ (‘Opobo’). Sherbro and Sulima are obtained from the petiole, the former from Raphia hookeri and the latter from Raphia palma-pinus (Gaertn.) Hutch., often with an admixture of Raphia hookeri fibres, whereas Calabar is extracted from the leaf sheath of Raphia hookeri. The leaf sheaths of Raphia palma-pinus are rather short and do not yield high quality fibre. Most of the raffia of commerce is produced in Madagascar from Raphia farinifera (Gaertn.) Hyl.
Although palm wine is the main product of Raphia hookeri in several regions, no production data are available. The wine is mainly used and traded locally. Distilled palm wine is also mainly traded locally although there is some trade between neighbouring countries.
Properties
Piassava fibre is water resistant, hard-wearing, and has the right balance between stiffness and elasticity to give a firm stroke to a broom and sufficient spring action to make the broom self-cleaning. The best piassava fibre is cylindrical with a firm wall and a soft core and a diameter of 1–1.5 mm. It is obtained from the sides (‘wings’) of the petiole, whereas fibre from the upper and lower surfaces is of only reasonable quality. Fibres near the central flattened ridge are woody and brittle. The central core of the petiole gives a soft fibre (‘straw’ or ‘piassava tow’) which may be used as a substitute for coir from coconut. The best quality Calabar fibre is obtained from the sides of the leaf sheath, i.e. not near the suture and not near the midrib. Fibre obtained from the midrib of the leaf sheath is softer and more pliable making it suitable for plaiting ropes. Calabar piassava is stiffer than Sherbro and Sulima and tends to be black, whereas Sherbro and Sulima are pale at harvest, turning darker during retting. Mature leaves yield higher quality piassava fibre than younger leaves. Raphia hookeri yields good quality raffia with high tenacity.
Both the stem and the petiole of Raphia hookeri are suitable as raw material for the paper industry. Stem fibres are mostly thick walled and, on average, 2.4 mm long and 30 µm wide. The width is rather variable, ranging from 17–46 µm. The fibres of the petioles are on average 1.7 mm long and 18 µm (10–27 µm) wide. Many fibres have scalloped walls. The pitted vessel elements of the stem are few in number but very large, up to 5 mm long and 350 µm wide, whereas those of the petioles are generally smaller. Pulp from Raphia hookeri also contains rounded, thick-walled parenchyma cells and spherical silica bodies. Dry stems consist of about 74% fibre, 25% parenchyma, and 1% vessel elements.
Palm wine obtained from Raphia hookeri is attractively milky-white in colour, but is weaker and less sought after than that from oil palm. When fresh, the sap tastes like ginger beer. The alcohol content of the sap increases from less than 2% to about 5% during the first 8 days of tapping, remaining constant thereafter. Leuconostoc and Lactobacillus bacteria are present in the early stages of fermentation, while the yeast Saccharomyces cerevisiae is mainly responsible for the alcohol fermentation.
The major fatty acids in mesocarp oil and seed oil are linoleic acid, palmitic acid and oleic acid. Mesocarp oil from Raphia hookeri resembles that from oil palm in colour, taste, odour and chemical composition, except that it contains more linoleic acid, giving it a higher unsaturated acid content. The fruit also contains toxic and antinutritional factors, such as hydrocyanic acid, tannins, oxalate and phytic acid. Cooking reduces the levels of these. The kernel contains per 100 g : moisture 11 g, protein 8 g, fat 1 g, carbohydrates 63 g, fibre 8 g and ash 9 g.
Adulterations and substitutes
Raphia species used for similar purposes as Raphia hookeri include Raphia africana Otedoh, Raphia farinifera, Raphia mambillensis Otedoh, Raphia palma-pinus, Raphia regalis Becc., Raphia sudanica A.Chev. and Raphia vinifera. The original sources of piassava fibre are Attalea funifera (‘Bahia piassava’ or ‘Bahia bass’) and Leopoldinia piassaba (‘Para piassava’ or ‘Monkey bass’), both from Brazil.
Description
Monoecious tree, trunk up to 10 m tall and 30 cm in diameter, occasionally with 1–4 suckers; upper part of trunk with blackish fibres (marcescent leaf-bases). Leaves arranged spirally, pinnate, up to 12 m long, erect, dark green and shining above, waxy and glaucous below; sheath 3–4 m long, unarmed, splitting opposite the petiole; petiole 3–4 m long; leaflets 1–1.5 m × 4–5 cm, about 200 on each side of the rachis, terminal segments gradually narrowing to a fine point and having spines on upper side of midrib and on margins. Inflorescence axillary, pendulous, 2.5 m or more long, branched to 2 orders, compressed-cylindrical, with crowded branches; branches bearing many curved ultimate branchlets in 4 rows but mostly compressed into one plane; branchlets 15–23 cm long, rigid; branches and branchlets with short-tubular, truncate bracts at base. Flowers unisexual; male flowers at apex of inflorescence branchlets, female flowers at base, 3-merous; male flowers 1.5–2.5 cm long, with 1 bracteole slightly longer than thick calyx with blunt lobes, corolla much longer than calyx, curved, with segments thickened near the tip, stamens (15–)18–22(–24), with erect, linear anthers; female flowers larger than male, with 2 bracteoles, calyx as in male, corolla about as long as calyx, with acuminate segments thickened near tip, staminodes 12–15, ovary superior, 3-celled, stigma sessile, recurved, subulate. Fruit a 1-seeded berry, inversely conical or ellipsoid, 6–12 cm × 4–5 cm, with stout beak 1–1.5 cm long, more or less obliquely tipped, covered with scales in (11–)12(–15) vertical rows; scales convex, slightly less broad than long, narrowly furrowed, reddish-brown or pale yellowish-brown with darker point, obtuse at the base, almost entire. Seed 6–7.5 cm × 3–3.5 cm, oblong, irregularly grooved; albumen narrowly ruminate. Seedling with hypogeal germination, with tap root and some adventitious roots; first 3–4 leaves strongly reduced and irregularly incised, subsequent leaf 50–100 cm long and with about 12 leaflets at each side of the rachis.
Other botanical information
Raphia comprises 28 species, mostly African, predominantly found in swampy areas. One species, Raphia taedigera (Mart.) Mart., is found in tropical America.
Three varieties of Raphia hookeri have been distinguished: Raphia hookeri var. hookeri, Raphia hookeri var. planifolia Otedoh and Raphia hookeri var. rubrifolia Otedoh. Locally, different forms of Raphia hookeri are recognized.
Anatomy
The hypodermis of Raphia hookeri leaflets consists of thick fibres arranged in a continuous ribbon-like layer with no discontinuities. In Raphia vinifera and Raphia sudanica the fibres are not arranged in a ribbon-like layer, but are discontinuous, resulting in less tenacity.
In both the stem and petiole the vascular system consists of bundles which are scattered throughout the ground tissue and the cortex is very narrow or non-existent. The peripheral vascular bundles of the central cylinder are congested and have a well-developed fibrous sheath. The vascular bundles are separated by parenchyma. In the inner part of the central cylinder, the vascular bundles are more diffuse than in the periphery. Stem fibres are more numerous than in the petiole, partly because the vascular bundles are closer and partly because the fibrous bundle sheaths are thicker in the central parts.
Growth and development
Raphia hookeri develops in accordance with Tomlinson's growth model. When young the main stem forms a few basal suckers. Raphia species have monocarpic stems, i.e. they flower and fruit only once, followed by death. Inflorescences are produced more or less simultaneously in the axils of the most distal leaves. Tapping for wine may damage the developing inflorescence, making flowering impossible and accelerating death. The time from planting to flowering in Raphia hookeri is 3–7 years. In Nigeria, Raphia hookeri flowers in May. The pericarp reaches maturity at 24–30 months, the seed matures in about 30–33 months. Lipid accumulation in the pericarp mainly occurs between 30–36 months after pollination. Ground squirrels, bats and birds feed on the mesocarp.
Ecology
Raphia hookeri occurs in freshwater swamps and on river banks in the Guinean Zone of West and Central Africa. It generally does not tolerate saline conditions; near the Guinea coast it is replaced by Raphia palma-pinus. In some places (e.g. southern Benin and south-eastern Nigeria) human activity (cutting of dicotyledonous trees, planting hookeri is the dominant species. The soils of Nigerian freshwater swamps are light textured and generally acidic.
Propagation and planting
Managed stands of Raphia hookeri are mostly left to rejuvenate naturally by seed. In Nigeria, selected trees are left untapped for this purpose. Occasionally, Raphia hookeri is propagated from seed. The germination period may range from 1–24 months, and the germination rate from 30–60%. Young plants are easily transplanted. In nurseries, a spacing of 30 cm × 30 cm is recommended. It has been claimed that seeds should be sown ventral side upwards, because the embryo is located on this side, but research has shown that seed orientation does not influence germination or seedling growth.
In Nigeria, Raphia hookeri sometimes serves as support for yams. In Benin, tomatoes, cassava, sugar cane, red pepper and other crops are sometimes grown on earth ridges in Raphia hookeri swamps.
Management
In West Africa, Raphia hookeri is exploited from natural stands, but it is also planted and tended on upland farms. Suckers are often removed by farmers to promote growth of the main stem.
Diseases and pests
Raphia hookeri in Nigeria is affected by seedling blight, caused by Glomerella cingulata. Symptoms are transparent yellow circular spots appearing on the youngest fully expanded leaves, later becoming necrotic and coalescing. The infection spreads from the tip to the base of the leaflet and may lead to leaflet shedding. Severely infected seedlings may die. Fruit rot, caused by Thielaviopsis paradoxa (synonym: Chalara paradoxa), also occurs in Nigeria, causing dark brown rot of the mesocarp. It is a weak pathogen entering fruit via wounds, sometimes killing the embryo, and leading to loss of planting material. The aphid Cerataphis palmae may cause considerable damage, e.g. in Nigeria.
Harvesting
Because palm wine from Raphia hookeri is highly prized, cultivators are reluctant to diminish plant vigour by cutting leaves for their fibre. However, dying leaves can be harvested for piassava with little effect on wine yields. Removing the leaf sheaths requires considerable leverage, and is usually a team effort. Stout poles, flattened at the end, are inserted into the suture of the lowest leaf sheath and the stem, and the sheath is levered away, while additional weight is applied to the petiole. As it is easier to remove the leaf sheaths from a fallen trunk, palms are often felled after tapping and before fibre harvesting. In Nigeria, external fibres covering the trunk are sometimes set on fire, after which the tree is felled with an axe, the leaves and lower trunk are cut off with a cutlass, and the leaf stalks are cut and removed from the base to the crown successively.
Tapping for palm wine begins when the first small leaf (2–3 m long) subtending an inflorescence appears. A cavity is cut in the stem just below the growing point and the resulting sap is collected in a calabash. When sap flow diminishes, the hole is enlarged until it is about 50 cm × 20 cm. Raphia can usually be tapped for 18–25 days before the tree dies. Unlike oil palm, Raphia palms are rarely felled before tapping. For maximum oil yields, the fruits should be harvested 36–42 months after pollination.
Yield
No data on fibre yield are available. Palm wine yields of 870 l have been recorded from a single tree in a 2-month period from cutting to death, but average yields are about 100 l per palm.
Handling after harvest
Piassava fibre extraction is different for leaf sheaths and petioles. The tissue of older leaf sheaths is already moribund and has started to soften, and the outer thicker and more brittle fibres can be stripped off or, in some areas, are removed by burning the trunk. Starting from the outer ‘wings’, the useful fibres are sequentially stripped by hand. When removal of the fibres is difficult, usually in younger leaf sheaths, the tissue is beaten with a stick or the trunk is left exposed to the elements until the tissue has softened. The traditional practice of fibre extraction from the petiole, with its more solid tissue and hard epidermis, is to split the petiole along the longitudinal axis into 3 or 4 splits, which are tied into bundles and immersed in water. The retting period varies from a few weeks to 2–3 months. After retting, the fibres can be stripped off relatively easily. Retting influences the appearance of the fibres. Sherbro and Sulima piassava, somewhat pale coloured at harvest, turn brownish on retting. Material retted in fresh running water tends to be pale brown, whereas material retted in stagnant swamp pools develops a reddish-brown tinge, which is attractive and leads to higher prices. The extracted fibres still have a coating of decomposing background tissue which has to be removed. In the case of Calabar piassava this coating is stripped by drawing the fibre through a cleft cut into a stick or palm petiole. In the case of Sherbro and Sulima, the retted strips are usually flogged over and drawn through a comb of pointed sticks. Fibres may also be separated and cleaned by hand. The cleanliness of the fibre has a large impact on quality and market value. Cleaned fibres may be spread out to dry in the sun for a few days. Further drying may occur under the eaves of houses or above fireplaces. Fibres which are not properly dried become mouldy and brittle and can be a fire hazard in warehouses and ships.
Fibre length is an important attribute as long fibres provide more opportunities for further processing. It is also important that bundles consist of fibres of uniform length. High quality Sherbro and Sulima fibres show little variation in length and are about 1.5 m long. Although shorter fibres are acceptable, they should not be shorter than 25–30 cm. The Sherbro and Sulima fibres are normally packed in bundles of 25 kg. Calabar fibres are more variable in length and require sorting into bundles of uniform length - a tedious and time-consuming task. Traditionally, bundles of fibres of differing lengths are transported to local markets, where they are weighed and priced. The buyer then mixes fibres from different sources before trimming and tying them into uniform bundles of 70–100 cm diameter.
Palm wine from Raphia hookeri is mostly consumed fresh, but can be distilled to make a strong alcoholic liquor.
Genetic resources
No germplasm collections of Raphia hookeri are known. Raphia hookeri is not threatened with extinction as it occurs over a very large area and is widely protected by farmers.
Prospects
Locally, Raphia hookeri will remain an important multipurpose palm, yielding various types of fibres, highly valued palm wine and a range of other products. Its importance in international trade as a source of African piassava fibre has declined sharply following the advent of plastic substitutes, but there is still demand for natural brush-fibres. This demand may even increase in the future as environmentally friendly, traditional products gain popularity.
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.
• Edem, D.O., Eka, O.U. & Ifon, E.T., 1984. Chemical evaluation of the nutritive value of the Raffia palm fruit (Raphia hookeri). Food Chemistry 15(1): 9–17.
• Faparusi, S.I., 1981. Sugars identified in Raphia palm wine. Food Chemistry 7(2): 81–86.
• Ilvessalo-Pfäffli, M.-S., 1995. Fiber atlas. Identification of papermaking fibers. Springer Verlag, Berlin, Germany. 400 pp.
• Opute, F.I., 1978. Mesocarp, seed and pollen lipids of Raphia palms. Journal of the Science of Food and Agriculture 29: 115–120.
• Otedoh, M.O., 1973. The production of piassava in Nigeria. Nigerian Agricultural Journal 10(2): 260–264.
• Profizi, J.P., 1986. Biologie et mode de gestion des marécages à Raphia hookeri Mann & Wendland au sud-est du Bénin. Journal d’Agriculture Traditionnelle et de Botanique Appliquée 33: 49–58.
• Russell, T.A., 1965. The Raphia palms of West Africa. Kew Bulletin 19(2): 173–196.
• Russell, T.A., 1968. Palmae. In: Hutchinson, J., Dalziel, J.M. & Hepper, F. (Editors). Flora of West Tropical Africa. 2nd edition. Volume 3, part 1. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. (pp. 159–169).
• Tuley, P., 1994. African bass/piassava – a historical perspective. Principes 38(1): 36–46.
Other references
• de Koning, J., 1983. La forêt de Banco. Part 2: La Flore. Mededelingen Landbouwhogeschool 83-01. Thesis Landbouwhogeschool Wageningen, the Netherlands. 921 pp.
• de Souza, S., 1982. Remarques anatomiques sur trois espèces de Raphia du Bénin: Raphia hookeri Mann & Wendl., R. vinifera P. Beauv. et R. sudanica A. Chev. Bulletin de l’Institut Français d’Afrique Noire, Série A 44(3–4): 280–294.
• Dransfield, J., 1986. Palmae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, the Netherlands. 55 pp.
• Enobakhare, D.A., 1994. Occurrence and distribution of Cerataphis palmae (Ghesquierei) (Homoptera: Pemphigidae) on Raphia palms in southern Nigeria. Insect Science and its Application 15(1): 101–104.
• Iremiren, G.O. & Onwubuya, I.I., 1985. Growth of Raphia nursery seedlings as affected by spacing, embryo orientation at sowing, shading and irrigation. Journal of the Nigerian Institute for Oil Palm Research 7(1): 76–85.
• Irvine, F.R., 1961. Woody plants of Ghana, with special reference to their uses. Oxford University Press, London, United Kingdom. 868 pp.
• Kirby, R.H., 1963. Vegetable fibres: botany, cultivation, and utilization. Leonard Hill, London, United Kingdom & Interscience Publishers, New York, United States. 464 pp.
• Letouzey, R., 1978. Notes phytogéographiques sur les palmiers du Cameroun. Adansonia 18(3): 293–325.
• Mansfeld, R., 1986. Verzeichnis landwirtschaftlicher und gärtnerischer Kulturpflanzen (ohne Zierpflanzen). 2nd edition, revised by J. Schultze-Motel. 4 volumes. Springer Verlag, Berlin, Germany. 1998 pp.
• Ndon, B.A., 1985. Some morphological and chemical characteristics of developing fruits of Raphia hookeri. Journal of Experimental Botany 36(172): 1817–1830.
• Okolo, E.C., 1988. Chromosome counts on Nigerian species of the genus Raphia. Principes 32(4): 156–159.
• Oruade-Dimaro, E.A., 1987. The occurrence of brown fruit rot of Raphia species in Nigeria. Nigerian Journal of Palms and Oil Seeds 8(1): 41–49.
• Oruade-Dimaro, E.A. & Ekundayo, C.A., 1992. Seedling blight disease of Raphia hookeri caused by Glomerella cingulata in Nigeria. Principes 36(1): 41–44.
• Otedoh, M.O., 1974. Raphia oil: its extraction, properties and utilization. Journal of the Nigerian Institute for Oil Palm Research 5(19): 45–49.
• Profizi, J.-P., 1988. Swampy area transformations by exploitation of Raphia hookeri (Arecaceae) in southern Benin (West Africa). Human Ecology 16(1): 87–94.
• Purseglove, J.W., 1972. Tropical crops. Monocotyledons. Volume 2. Longman, London, United Kingdom. 273 pp.
• Pyykkö, M., 1985. Anatomy of the stem and petiole of Raphia hookeri (Palmae). Annales Botanici Fennici 22: 129–138.
• Rehm, S., 1994. Multilingual dictionary of agronomic plants. Kluwer Academic Publishers, Dordrecht, the Netherlands. 286 pp.
• Steinkraus, K.H. (Editor), 1996. Handbook of indigenous fermented foods. 2nd edition. Marcel Dekker, New York. 776 pp.
• Wright, C.H., 1902. Palmae. In: Thiselton-Dyer, W.T. (Editor). Flora of Tropical Africa. Volume 8. Lovell Reeve & Co, London, United Kingdom. (pp. 104-107).
Sources of illustration
• de Kerchove de Denterghem, O., 1878. Les palmiers, histoire iconographique. J. Rothschild, Paris, France. (p. 37).
• Hawthorne, W., 1990. Field guide to the forest trees of Ghana. Natural Resources Institute, for the Overseas Development Administration, London, United Kingdom. (p. 224)
• Russell, T.A., 1965. The Raphia palms of West Africa. Kew Bulletin 19(2): 173–196.
Author(s)
M. Brink
PROSEA Publication Office, Wageningen University, P.O. Box 341, 6700 AH Wageningen, the Netherlands


Editors
L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, the Netherlands
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, the Netherlands
Associate Editors
S.D. Davis
Centre for Economic Botany, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE, United Kingdom
M. Chauvet
INRA Communication, 2 Place Viala, 34060 Montpellier, Cedex 1, France
J.S. Siemonsma
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, the Netherlands
Illustrator
W. Wessel-Brand
Biosystematics Group, Wageningen University, Generaal Foulkesweg 37, 6703 AH Wageningen, the Netherlands

Correct citation of this article:
Brink, M., 2002. Raphia hookeri G.Mann & H.Wendl.. Record from Protabase. Oyen, L.P.A. & Lemmens, R.H.M.J. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, the Netherlands.
Distribution Map Raphia hookeri – wild


1, plant habit; 2, leaflet; 3, inflorescence; 4, fruit
Redrawn and adapted by W. Wessel-Brand