1. Family: Fabaceae Lindl.
    1. Genus: Cajanus Adans.
      1. Cajanus cajan (L.) Huth

        Cajanus cajan, more commonly known as pigeon pea, is a drought-resistant crop important for small scale farmers in semi-arid areas where rainfall is low. Pigeon pea contains high levels of protein and important B vitamins and is therefore especially important for people living on subsistence diets. In India, pigeon pea seeds come in a huge variety of flavours and colours, ranging from bitter to sweet and from black to creamy white.

    [KSP]

    Kew Species Profiles

    General Description

    Cajanus cajan, more commonly known as pigeon pea, is a drought-resistant crop important for small scale farmers in semi-arid areas where rainfall is low. Pigeon pea contains high levels of protein and important B vitamins and is therefore especially important for people living on subsistence diets. In India, pigeon pea seeds come in a huge variety of flavours and colours, ranging from bitter to sweet and from black to creamy white.

    Species Profile
    Geography and distribution

    Pigeon pea was first domesticated in India where it has been growing for thousands of years. Around 2,000 BC, a second centre of pigeon pea diversity was developed in East Africa and from there, probably as a result of the slave trade, the crop was brought to the Americas. Today pigeon pea is grown throughout tropical and subtropical regions of the world; the largest producer is India, followed by East Africa and Central America. 

    Description

    Overview: Cajanus cajan is an erect shrub up to 4 metres tall, with roots that extend up to 2 metres into the soil. Its main stem is erect, ribbed and the plant has many secondary branches. 

    Leaves: The leaves are alternate along the stems and are composed of three leaflets (tri-foliolate) and they are positioned alternately along the stem. The petiole (the stalk which connects the leaf to the stem) is 1-8 cm long and grooved above. The leaflets are elliptical (like a stretched circle when flat) to lance-shaped (lanceolate) and are 2.5-13.5 cm long to 1-5.5 cm wide. The leaflets are green above and a silvery grey-green beneath and are covered on their lower surfaces in small yellow glands. 

    Flowers: The stalked flowers are arranged along an unbranched axis (a raceme). The racemes are axillary (arising from the point between the main stem and a leaf). The flowers are yellow and are papilionaceous, typical of species belonging to the Leguminosae subfamily Papilionoideae, and resemble, for example, the pea ( Pisum sativum ) flower. Each flower has 10 stamens, 9 of which are fused into a partial tube, with the tenth stamen free. The ovary is positioned above the sepals, petals and stamens. The style is curved. 

    Fruit: The fruit is a straight or sickle-shaped pod 2-13 cm long x 0.5-1.5 cm wide containing up to 9 seeds. The seeds are 4-9 mm x 3-8 mm and can be white, brown, purplish, black or mottled. 

    Threats and conservation

    Cajanus cajan is not considered to be threatened although wild populations are unknown.

    Uses

    Pigeon pea is cultivated mainly for its edible seeds, which are rich in protein and add a nutty flavour to many food preparations.

    In India, pigeon pea is most commonly used in 'dhal' (soaked dried, hulled, and split seeds) and in many other parts of Asia the seeds are used instead of soya bean to make tempeh or tofu.In Africa, the dried seeds are typically used in sauces to accompany staple food preparations such as rice, yam and cassava. The immature seeds and pods of pigeon pea can be eaten fresh as a vegetable in soups and sauces and when ripe, the seeds are often soaked first before frying or boiling them into porridge.In Central America pigeon pea seeds are canned and frozen so that they can be stored and eaten when the crop is no longer in season.

    Besides being an excellent food source for humans, the seed pods and the leaves of pigeon pea are used to feed livestock and the plants themselves make a useful living fence, windbreaker, shade cover crop and support for vanilla.

    Pigeon pea has the ability to fix atmospheric nitrogen through bacteria housed in root nodules, making it a good fertiliser for the soil.

    The stems and branches are used for basketry, thatching, fencing and as fuel. It also serves as a host for silkworm and the lac insect.

    The leaves of pigeon pea are used in traditional medicine to treat diarrhoea, gonorrhoea, measles, burns, eye infections, earache, sore throat, sore gums, toothache, anaemia, intestinal worms, dizziness and epilepsy. Remedies prepared from the root of the plant are taken to treat cough, stomach problems and syphilis. The roots are chewed to relieve toothache and in Madagascar the leaves are used to clean the teeth. 

    Crop wild relatives of pigeon pea

    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 pigeon pea, 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 Kew’s Millennium Seed Bank vault.

    Description of seeds: Average weight of 1,000 seeds = 98.5 g

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

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

    Germination testing: Successful

    This species at Kew

    Pressed and dried specimens of pigeon pea 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.

    Distribution
    India
    Ecology
    Pigeon pea grows in tropical and subtropical regions. The crop thrives when annual rainfall is 600–1000 mm, but it is tolerant of drought and can be grown in areas with less than 600mm rainfall. Pigeon pea can grow on a wide range of soil types.
    Conservation
    Widespread in cultivation. It is not known in the wild, but often occurs naturalized as an escape from cultivation.
    [KSP]
    Use
    Food, fodder, medicine, living fence, basketry, fuel.

    Images

    Distribution

    Found In:

    Assam, India, West Himalaya

    Introduced Into:

    Afghanistan, Andaman Is., Angola, Bahamas, Bangladesh, Benin, Bermuda, Bismarck Archipelago, Bolivia, Brazil Northeast, Brazil South, Burkina, Burundi, Cambodia, Cameroon, Cape Verde, Cayman Is., Central African Repu, Chad, China South-Central, China Southeast, Colombia, Comoros, Congo, Cook Is., Cuba, Djibouti, Dominican Republic, East Himalaya, Ecuador, Egypt, Eritrea, Ethiopia, Florida, French Guiana, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Gulf of Guinea Is., Guyana, Hainan, Haiti, Honduras, Ivory Coast, Jamaica, Jawa, Kenya, KwaZulu-Natal, Laccadive Is., Laos, Leeward Is., Lesser Sunda Is., Liberia, Madagascar, Malawi, Malaya, Mali, Mauritius, Mexico Southwest, Mozambique, Myanmar, Namibia, Nepal, New Caledonia, New Guinea, New South Wales, Nicobar Is., Niger, Nigeria, Northern Provinces, Pakistan, Paraguay, Peru, Philippines, Puerto Rico, Queensland, Rwanda, Réunion, Saudi Arabia, Senegal, Seychelles, Sierra Leone, Society Is., Somalia, Southwest Caribbean, Sri Lanka, Sudan, Sulawesi, Sumatera, Suriname, Swaziland, Tadzhikistan, Taiwan, Tanzania, Thailand, Togo, Transcaucasus, Trinidad-Tobago, Turkmenistan, Uganda, Uzbekistan, Venezuela, Vietnam, Windward Is., Yemen, Zambia, Zaïre, Zimbabwe

    Common Names

    English
    Pigeon pea

    Cajanus cajan (L.) Huth appears in other Kew resources:

    First published in Helios 11: 133 (1893)

    Accepted in:

    • [1] (2016) Flore du Gabon 49: 1-407. Muséum National d'Histoire Naturelle, Paris
    • [2] Sykes, W.R. (2016) Flora of the Cook Islands . National Tropical Botanical Garden, Hawaii
    • [3] Darbyshire, I., Kordofani, M., Farag, I., Candiga, R. & Pickering, H. (eds.) (2015) The Plants of Sudan and South Sudan . Kew publishing, Royal Botanic Gardens, Kew
    • [4] (2014) Australian Plant Census (APC) . Council of Heads of Australian Herbaria. http://www.anbg.gov.au/chah/apc/index.html
    • [5] (2014) Phytotaxa 171: 1-78
    • [6] (2013) Monographs in Systematic Botany from the Missouri Botanical Garden 127: 1-1741. Missouri Botanical Garden
    • [7] (2012) Indian Journal of Forestry 35: 79-84
    • [8] (2012) Korean Journal of Plant Taxonomy 42: 222-246
    • [9] (2012) Nelumbo 54: 39-91
    • [10] (2012) Smithsonian Contributions to Botany 98: 1-1192
    • [11] Garcia-Mendoza, A.J. & Meave, J.A. (eds.) (2012) Diversidad florística de Oaxaca: de musgos a angiospermas (colecciones y listas de especies) , ed. 2: 1-351. Instituto de Biología, Universidad Nacional Autónoma de México
    • [12] (2010) Folia Geobotanica 45: 1-57
    • [13] (2010) Taxonomania 30: 1-307
    • [15] Flora of China Editorial Committee (2010) Flora of China 10: 1-642. Science Press (Beijing) & Missouri Botanical Garden Press (St. Louis)
    • [16] (2009) Scripta Botanica Belgica 41: 1-517
    • [17] (2008) Journal of Economic and Taxonomic Botany 32: 403-500
    • [18] (2008) Monographs in Systematic Botany from the Missouri Botanical Garden 107: 1-3348. Missouri Botanical Garden
    • [19] (2008) Strelitzia 22: 1-279. National Botanical Institute, Pretoria
    • [20] Hokche, O., Berry, P.E. & Huber, O. (eds.) (2008) Nuevo Catálogo de la Flora Vascular de Venezuela . Fundación Instituto Botánico de Venezuela
    • [22] Nelson Sutherland, C.H. (2008) Catálogo de las plantes vasculares de Honduras. Espermatofitas . SERNA/Guaymuras, Tegucigalpa, Honduras
    • [24] Akoègninou, A., van der Burg, W.J. & van der Maesen, L.J.G. (eds.) (2006) Flore Analytique du Bénin . Backhuys Publishers
    • [26] Catarino, L., Sampaio Martins, E., Pinto-Basto, M.F. & Diniz, M.A. (2006) Plantas Vasculares e Briófitos da Guiné-Bissau . Instituto de investigação científica tropical, Instituto Português de apoio ao desenvolvimento
    • [27] Sita, P. & Moutsambote, J.-M. (2005) Catalogue des plantes vasculaires du Congo , ed. sept. 2005: 1-158. ORSTOM, Centre de Brazzaville
    • [28] Lock, J.M. & Ford, C.S. (2004) Legumes of Malesia a Check-List . Royal Botanic Gardens, Kew
    • [29] (2003) Strelitzia 14: 1-1231. National Botanical Institute, Pretoria
    • [30] Kumar, S. & Sane, P.V. (2003) Legumes of South Asia. A Checklist . Royal Botanic Gardens, Kew
    • [31] Du Puy, D.J., Labat, N.-N., Rabevohitra, R., Villiers, J.-F., Bosser, J. & Moat, J. (2002) The Leguminosae of Madagascar . Royal Botanic Gardens, Kew
    • [32] (2001) Flora Zambesiaca 3(5): 1-261. Royal Botanic Gardens, Kew
    • [33] Dy Phon, P. (2000) Dictionnaire des plantes utilisées au Cambodge . chez l'auteur, Phnom Penh, Cambodia
    • [34] Govaerts, R. (1999) World Checklist of Seed Plants 3(1, 2a & 2b): 1-1532. MIM, Deurne
    • [35] Jørgensen, P.M. & León-Yánes, S. (eds.) (1999) Catalogue of the Vascular Plants of Ecuador . Missouri Botanical Garden Press, St. Louis
    • [36] Isely, D. (1998) Native and Naturalized Leguminosae (Fabaceae) of the United States . Monte L. Bean Life Science Museum. Brigham Young University, Provo, Utah
    • [37] Boggan, J. Funck, V. & Kelloff, C. (1997) Checklist of the Plants of the Guianas (Guyana, Surinam, Franch Guiana) ed. 2: 1-238. University of Guyana, Georgetown
    • [38] Wood, J.R.I. (1997) A handbook of the Yemen Flora . Royal Botanic Gardens, Kew
    • [42] Lock, J.M. & Heald, J. (1994) Legumes of Indo-China a checck-list . Royal Botanic Gardens, Kew
    • [43] MacKee, H.S. (1994) Catalogue des plantes introduites et cultivées en Nouvelle-Calédonie , ed. 2: 1-164. Museum national d'histoire naturelle, Paris
    • [44] (1993) Monographs in Systematic Botany from the Missouri Botanical Garden 45: i-xl, 1-1286. Missouri Botanical Garden
    • [45] Thulin, M. (ed.) (1993) Flora of Somalia 1: 1-493. The Royal Botanic Gardens, Kew
    • [46] Jones, M. (1991) A checklist of Gambian plants . Michael Jones, The Gambia College
    • [47] Lebrun, J.p., Toutain, B., Gaston, A. & Boudet, G. (1991) Catalogue des Plantes Vasculaires du Burkina Faso . Institut d' Elevage et de Médecine Vétérinaire des Pays Tropicaux, Maisons Alfort
    • [48] (1989 publ. 1990) Flora of Ethiopia and Eritrea 3: 1-659. The National Herbarium, Addis Ababa University, Ethiopia & The Department of Systematic Botany, Upps
    • [49] Lock, J.M. (1989) Legumes of Africa a check-list . Royal Botanic Gardens, Kew
    • [50] Milgahid, A.M. (1989) Flora of Saudi Arabia , ed. 3, 2: 1-282. University Libraries, King Saud University, Riyadh, Saudi Arabia
    • [51] (1984) Flora Iranica 157: 1-499. Naturhistorisches Museums Wien
    • [52] Brunel, J.F., Hiepo, P. & Scholz, H. (eds.) (1984) Flore Analytique du Togo Phanérogames: 1-751. GTZ, Eschborn
    • [54] Boulvert, Y. (1977) Catalogue de la Flore de Centrafrique 2(1): 1-85. ORSTROM, Bangui
    • [55] Berhaut, J. (1976) Flore illustrée du Sénégal 5: 1-658. Gouvernement du Sénégal, Ministère du développement rural direction des eaux et forêta, Dakar
    • [56] Peyre de Fabregues, B. & Lebrun, J.-P. (1976) Catalogue des Plantes Vascularies du Niger . Institut d' Elevage et de Médecine Vétérinaire des Pays Tropicaux, Maisons Alfort
    • [57] Lebrun, J.-P., Audru, J., Gaston, A. & Mosnier, M. (1972) Catalogue des Plantes Vasculaires du Tchad Méridional . Institut d' Elevage et de Médecine Vétérinaire des Pays Tropicaux, Maisons Alfort

    Literature

    • [14] Beentje, H. (2010). The Kew Plant Glossary: an Illustrated Dictionary of Plant Terms. Royal Botanic Gardens, Kew.
    • [21] Mabberley, D.J. (2008). Mabberley’s Plant-book: a Portable Dictionary of Plants, their Classification and Uses. Third edition. Cambridge University Press, Cambridge.
    • [23] Royal Botanic Gardens, Kew (2008). Seed Information Database (SID). Version 7.1.
    • [25] Brink, M. & Belay, G. (2006). Cereals and Pulses: Volume 1 of Plant Resources of Tropical Africa. PROTA.
    • [39] Yakovlev, G.P., Sytin, A.K. & Roskov, Y.R. (1996) Legumes of Northern Eurasia. A checklist . Royal Botanic Gardens, Kew
    • [40] Gonzalez, F., Nelson Diaz, J. & Lowry, P. (1995) Flora Illustrada de San Andrés y Providencia . Universidad Nacional de Colombia, Instituto de Ciencias Naturales, Colombia
    • [41] Audru, J., Cesar, J. & Lebrun, J.-P. (1994) Les Plantes Vasculaires de la République de Djibouti. Flore Illustrée 1: 1-336. CIRAD, Départerment d'Elevage et de Médecine vétérinaire, Djibouti
    • [53] Duke, J. A. (1981). Handbook of Legumes of World Economic Importance. New York: Plenum Press.
    • [58] Britton, N. (1918) Flora of Bermuda . Charles Scribner's Sons, New York

    Sources

    Kew Names and Taxonomic Backbone
    The International Plant Names Index and World Checklist of Selected Plant Families (2017). Published on the internet at http://www.ipni.org and http://apps.kew.org/wcsp
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    Kew Species Profiles
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    [D] http://creativecommons.org/licenses/by-nc-sa/3.0

    Legumes of the World Online
    [E] Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by-nc-sa/3.0/

    Kew Science Photographs
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