1. Family: Fabaceae Lindl.
    1. Genus: Vigna Savi
      1. Vigna unguiculata (L.) Walp.

        Vigna unguiculata is a leguminous crop plant belonging to the same genus as bambara groundnut. It was first domesticated in West Africa 5,000-6,000 years ago and today is grown commercially in over 33 countries. It is a hardy crop which thrives in sandy soils and is relatively tolerant of drought. It is considered the most important pulse crop in the savannahs of West and Central Africa where it is also cultivated as a vegetable and to feed livestock.


    Kew Species Profiles

    General Description

    Vigna unguiculata is a leguminous crop plant belonging to the same genus as bambara groundnut. It was first domesticated in West Africa 5,000-6,000 years ago and today is grown commercially in over 33 countries. It is a hardy crop which thrives in sandy soils and is relatively tolerant of drought. It is considered the most important pulse crop in the savannahs of West and Central Africa where it is also cultivated as a vegetable and to feed livestock.

    Species Profile
    Geography and distribution

    Cowpea originated in Africa and today the greatest diversity of cowpea can be found in West Africa in the savanna regions of Burkino Faso, Ghana, Togo, Benin, Niger, Nigeria, and Cameroon. Cowpea was introduced to Europe, probably around 300 BC and to India 200 BC. The Spanish introduced cowpea to tropical America in the 17th century and the crop is grown widely in the United States, the Caribbean region and Brazil.

    As a result of human selection, cowpea has diversified into two cultivar groups: 

    Sesquipedalis - has long pods and is used as a vegetableBiflora - is cultivated for its pods, dry seeds and for fodder Description

    Overview: Vigna unguiculata can be either an annual (completing its lifecycle in one year) or a perennial (living for several years) herb. Some types are erect and trailing and other are climbing herbs up to 4 metres long. The plant has a well-developed taproot with many lateral roots extending from it. 

    Leaves:  Positioned alternately along the stem and composed of three leaflets. The petiole, the appendage which holds the leaf is up to 15 cm long, and in some cases 25 cm long, grooved above and swollen at the base. 

    Flowers: The flowers which are pink to purple (sometimes white within the var. unguiculata cultivar group Melanophthalmus) are clustered towards the top of an unbranched axis (known as a raceme). The flowers are papilionaceous, typical of species belonging to the subfamily Papilionoideae, and resemble, for example, the pea flower. Each flower has 10 stamens (male reproductive organs), nine of which are fused together and one free. The ovary (female reproductive organ) is 1.5 cm long. 

    Fruit: A cylindrical seed pod 8-30 cm long (in some cases 120 cm long), is pale brown when ripe and bears 8-30 seeds. The seeds are oblong to globose (spherical) 0.5-1 cm long and can be black, brown, pink or white. The hilium (the scar left on the seed from its attachment point to the placenta) is oblong, covered with a white tissue with a blackish rim. 


    Cowpea is a crop cultivated mainly for its seeds, which can be cooked and eaten alone or mixed in with other vegetables and spices to produce a nutritious bean soup. 

    Cowpea is eaten in large parts of Africa and in many areas it is the preferred pulse. In West Africa, cowpea seeds are ground into flour and mixed with onions and spices to make cakes which are either deep dried (‘akara balls’) or steamed (‘moin moin’) for a delicious snack. Cowpea flour can also be processed into crackers and baby foods, as is the case in Senegal, Ghana and Benin. In the United States, green seeds are sometimes roasted like peanuts.

    Besides the seeds, the leaves and pods of cowpea are eaten as vegetables which can be served boiled or fried. Many people dry the leaves in the sun to preserve them so that they can be eaten during the dry season when food is scarce. The best leaves to use are those picked towards the end of the season, because these tend to grow under conditions of stress and are generally tastier. 

    Cooked cowpea pods are more typical of Asian cuisine than African cuisine. In some parts of Africa, such as Ethiopia and Sudan, the roots are occasionally eaten. 

    The high protein content of cowpea makes it an excellent fodder crop. Cowpea is cultivated for fodder in West Africa, Asia, and Australia; it is used for grazing or mixed in with dry cereals for animal feed.

    In Nigeria some varieties of cowpea are cultivated for their strong fibre which is used to make fishing gear as well as to produce good quality paper. In the United States cowpea is grown for green manure. The dry seeds also make a good alternative to coffee.

    Various parts of the cowpea are used medicinally. The leaves and seeds are applied to skin infections as a poultice, the leaves are chewed to relieve toothache and powdered carbonized seeds are applied to insect stings. The roots are used as treatment for epilepsy, chest pain, constipation and as an antidote to snakebites.

    Its ability to fix nitrogen from the air makes cowpea a good fertiliser for the soil. In rice farming, farmers grow cowpea either before or after the rice crop, as this is found to increase the food production from the land area.

    In folklore, cowpea is used in sacrifices by the Hausa and Yoruba tribes to drive away evil and to pacify the spirits of sickly children. 

    Crop wild relatives of cowpea

    The Millennium Seed Bank and the Global Crop Diversity Trust are engaged in a ten-year project, called 'Adapting Agriculture to Climate Change'. The project aims to protect, collect and prepare the wild relatives of 29 key food crops, including cowpea, so that they are available to pre-breeders for the development of new varieties that are more resilient to the effects of climate change.

    Millennium Seed Bank: Seed storage

    The Millennium Seed Bank Partnership aims to save plants worldwide, focusing on those plants which are under threat and those which are of most use in the future. Once seeds have been collected they are dried, packaged and stored at -20°C in our seed bank vault.

    Description of seeds: Average 1,000 seed weight = 103 g

    Number of seed collections stored in the Millennium Seed Bank: Five

    Seed storage behaviour: Orthodox (the seeds of this plant can be dried to low moisture contents without significantly reducing their viability. This means they are suitable for long-term frozen storage such as at the MSB)

    Germination testing: Successful

    This species at Kew

    Pressed and dried specimens of cowpea are held in Kew's Herbarium, where they are available to researchers by appointment. Details and images of some of these specimens can be seen online in Kew's Herbarium Catalogue. 

    Brazil, Burkina Faso, Cameroon, Niger, USA
    Wild types grow well in savannah vegetation, in disturbed localities or as a weed at up to 1,500m altitude. It can also be found in sandy areas, coastlines, woodland, forest edges or swampy areas.
    Widespread in cultivation.

    Leguminosae, B. Mackinder, R. Pasquet, R. Polhill and B. Verdcourt. Flora Zambesiaca 3:5. 2001

    Annual or perennial erect trailing or climbing herb, 0.5–3 m long.
    Stem striate, glabrous, scabrous, pubescent or hairy.
    Leaflets 3, 1.5–16.5 × 1–12.5 cm, ovate, rhombic or lanceolate to linear, the laterals oblique, all entire or terminal leaflets subhastate to deeply 3-lobed at the base and laterals lobed on the outer margin, shortly acuminate or subacute and mucronulate, acute to rounded at the base, glabrous to pubescent on both surfaces; petiole 1.5–13 cm long; rhachis 0.6–2.5 cm long; stipules submedifixed, constricted at the point of attachment, multinerved, upper part lanceolate, 6–20 mm long, spur narrower, 2–6 mm long.
    Peduncle 2–36 cm long.
    Flower pink to purple, rarely white (mainly within var. unguiculata cultivar-group Melanophthalmus), 15–33 mm long; pedicel 1–3 mm long, not expanding as the pod matures; bracteoles 3–6 mm long, spathulate or lanceolate, 1–3-nerved.
    Calyx glabrous or pubescent; tube 2–5.5 mm long; lobes subequal, ciliolate, the upper pair joined for about half their length to form a broad lobe bifid at the apex or only at the base.
    Standard with 2 parallel widely spaced appendages.
    Pod 8–10 × 2.5–5 mm (except within cultivated races), linear-cylindrical, glabrous, scabrous, or pubescent.
    Seed 4–6.5 × 2–4.5 mm (except within cultivated races); hilum one third to half the longest dimension, excentric; rim aril slightly developed.

    Papilionaceae, Hutchinson and Dalziel. Flora of West Tropical Africa 1:2. 1958

    Stems annual but often stout, subglabrous, twining
    On trees, etc.
    Flowers white and mauve-tinged or pink or yellow.

    Leguminosae, J. B. Gillett, R. M. Polhill & B. Verdcourt. Flora of Tropical East Africa. 1971

    Annual or perennial erect trailing or climbing herb, 1–3 m. long.
    Stems striate, glabrous or slightly hairy particularly near the petiole-bases, sometimes with minute stiff hook-like hairs.
    Leaflets 3, ovate, rhomboid or lanceolate, the laterals oblique, 1·5–16·5 cm. long, 1–12·5 cm. wide, all entire or terminal leaflets subhastate to 3-lobed at the base and laterals lobed on the outer margin, shortly acuminate or subacute and mucronulate, acute to rounded at the base, glabrous or sparsely pubescent on both surfaces; petioles 1·5–13 cm. long; rhachis 0·6–2·5 cm. long; petiolules 2–5 mm. long; stipules submedifixed, constricted at the point of attachment, upper part lanceolate, 0·6–2 cm. long, spur narrower, 2–6 mm. long.
    Inflorescences axillary, few-several-flowered; rhachis 0·5–4(–5) cm. long; peduncle 2–36 cm. long, usually minutely uncinulate pubescent towards the apex; pedicels 1–2(–4) mm. long; bracts deciduous, lanceolate, 3–5 mm. long; bracteoles ± persistent, spathulate, 3–5 mm. long.
    Calyx glabrous; tube 3–5·5 mm. long; lobes triangular-lanceolate, 2·5–14 mm. long, acuminate, ciliolate; upper pair joined for about half their length or only at the base.
    Standard white, greenish, yellow or lilac-purple, paler outside, round, 1·2–3·3 cm. long, 1–3·2(–4) cm. wide, rounded or emarginate, glabrous; wings blue to purple; keel usually white or pale, not twisted.
    Pods erect or eventually hanging in cultivated forms, linear-cylindrical, 5·5–10(–90 in some cultivated races) cm. long, 3–11 mm. wide, glabrous or minutely verruculose.
    Seeds white to dark red or black, often mottled with black or brown, oblong or reniform, longest dimension 3·5–5(–12) mm., shorter dimension 2–3·5(–6·5) mm., 2·2(–4·5) mm. thick; hilum one-third to half the longest dimension, eccentric; rim-aril slightly developed.
    Food, fodder, medicine, paper making, fishing material.



    Found In:

    Angola, Benin, Botswana, Cameroon, Cape Provinces, Cape Verde, Caprivi Strip, Central African Repu, Congo, Eritrea, Ethiopia, Gambia, Ghana, Guinea-Bissau, Gulf of Guinea Is., Ivory Coast, Kenya, KwaZulu-Natal, Malawi, Mali, Mauritania, Mozambique, Namibia, Nigeria, Northern Provinces, Rwanda, Senegal, Sierra Leone, Sudan, Swaziland, Tanzania, Togo, Zambia, Zaïre, Zimbabwe

    Introduced Into:

    Alabama, Andaman Is., Arkansas, Assam, Bangladesh, Bismarck Archipelago, Brazil Southeast, Brazil West-Central, Burkina, Cambodia, Chad, Colombia, Cuba, Dominican Republic, East Himalaya, Ecuador, Fiji, Florida, French Guiana, Georgia, Guatemala, Guyana, Haiti, Honduras, Illinois, India, Iraq, Jamaica, Jawa, Kazakhstan, Kirgizstan, Korea, Laccadive Is., Laos, Leeward Is., Louisiana, Madagascar, Mexico Southwest, Mississippi, Myanmar, Nepal, New Caledonia, New Guinea, North Carolina, North Caucasus, Pakistan, Philippines, Puerto Rico, Queensland, Somalia, South Carolina, Sri Lanka, Suriname, Tadzhikistan, Thailand, Transcaucasus, Turkmenistan, Uganda, Ukraine, Uzbekistan, Vietnam, West Himalaya, Windward Is., Yemen

    Common Names


    Vigna unguiculata (L.) Walp. appears in other Kew resources:

    Date Identified Reference Herbarium Specimen Type Status
    Jul 1, 2010 Mackinder, B. [175], Cameroon K000027477
    Jul 1, 2010 Mackinder, B. [196], Cameroon K000027480
    Jan 1, 2007 Gosline, W.G. [146], Cameroon 63777.000
    Royen van [s.n.], India K000117607 Unknown type material
    Meerburgh Herb. [25], India K000117608 Unknown type material

    First published in Repert. Bot. Syst. 1: 779 (1843)

    Accepted in:

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