Varieties of soybean seeds, a popular legume

A legume /ˈlɛɡʲuːm/ in botanical writing is a plant in the family Fabaceae (or Leguminosae), or a fruit of these specific plants. A legume fruit is a simple dry fruit that develops from a simple carpel and usually dehisces (opens along a seam) on two sides. A common name for this type of fruit is a pod, although the term "pod" is also applied to a few other fruit types, such as vanilla and radish. Well-known legumes include alfalfa, clover, peas, beans, lentils, lupins, mesquite, carob, soy, and peanuts. Locust trees (Gleditsia or Robinia), wisteria, and the Kentucky coffeetree (Gymnocladus dioicus) are also legumes.^[1] They are referred in India as Kathod or pulses ^[2]

History[link]

This unreferenced section requires citations to ensure verifiability.

Plantation of "yardlong beans" locally called "sitaw" (Vigna unguiculata subsp. sesquipedalis), San Ildefonso, Bulacan.

Pea pods

The term legume is derived from the Latin word legumen (with the same meaning as the English term), which is believed to come from the verb legere, meaning "to gather." English borrowed the term from the French légume, which in modern language refers to any kind of vegetable. (The English word legume for the plant family translates into French as légumineuse.)

The history of legumes is tied in closely with that of human civilization, appearing early in Asia, the Americas (the common Phaseolus bean in several varieties), and Europe (broad beans), where they became a staple, essential for supplementing protein where meat was less available.

Fixation of nitrogen in the soil[link]

This unreferenced section requires citations to ensure verifiability.

Legume plants are notable for their ability to fix atmospheric nitrogen, thanks to a symbiotic relationship with bacteria (rhizobia) found in root nodules of these plants. The ability to form this mutualism reduces fertilizer costs for farmers and gardeners who grow legumes, and allows legumes to be used in a crop rotation to replenish soil that has been depleted of nitrogen. The nitrogen fixation ability of legumes is enhanced by the availability of calcium in the soil and reduced by the presence of ample nitrogen.

Legume seed and foliage have a comparatively higher protein content than non-legume material, probably due to the additional nitrogen that legumes receive through nitrogen-fixation symbiosis. The high protein content makes them desirable crops in agriculture.

Uses by humans[link]

Freshly dug peanuts (Arachis hypogaea), indehiscent legume fruits

White clover, a forage crop

Farmed legumes can belong to many agricultural classes, including forage, grain, blooms, pharmaceutical/industrial, fallow/green manure, and timber species. Most commercially farmed species fill two or more roles simultaneously, depending upon their degree of maturity when harvested.

Forage legumes are of two broad types. Some, like alfalfa, clover, vetch (Vicia), stylo (Stylosanthes), or Arachis, are sown in pasture and grazed by livestock. Other forage legumes such as Leucaena or Albizia are woody shrub or tree species that are either broken down by livestock or regularly cut by humans to provide livestock feed.

Grain legumes are cultivated for their seeds, and are also called pulses. The seeds are used for human and animal consumption or for the production of oils for industrial uses. Grain legumes include beans, lentils, lupins, peas, and peanuts.^[3]

Legume species grown for their flowers include lupins, which are farmed commercially for their blooms as well as being popular in gardens worldwide.^{[citation needed]} Industrially farmed legumes include Indigofera and Acacia species, which are cultivated for dye and natural gum production, respectively.^{[citation needed]} Fallow/green manure legume species are cultivated to be tilled back into the soil in order to exploit the high levels of captured atmospheric nitrogen found in the roots of most legumes. Numerous legumes farmed for this purpose include Leucaena, Cyamopsis, and Sesbania species. Various legume species are farmed for timber production worldwide, including numerous Acacia species and Castanospermum australe.^{[citation needed]}

Nutritional facts[link]

Legumes contain relatively low quantities of the essential amino acid methionine - however, this should not be a problem if an adequate amount of protein is consumed.

According to the protein combining theory, legumes should be combined with another protein source such as a grain in the same meal, to balance out the amino acid levels. Protein combining has lost favor as theory (with even its original proponent, Frances Moore Lappé, rejecting the need for protein combining in 1981^[4]) - a variety of protein sources is considered healthy, but these do not have to be consumed at the same meal. In any case, vegetarian cultures often serve legumes along with grains, which are low in the essential amino acid lysine, creating a more complete protein than either the beans or the grains on their own.

Common examples of such combinations are dal with rice by Indians, and beans with corn tortillas, tofu with rice, and peanut butter with wheat bread.^[5]

References[link]

External links[link]

Look up legume in Wiktionary, the free dictionary.

Wikisource has the text of the 1920 Encyclopedia Americana article Legume.

Media related to Legumes at Wikimedia Commons

• AEP - European association for grain legume research
• Lupins - Geography, classification, genetic resources and breeding
• ILDIS - International Legume Database & Information Service
• Bioversity International The significance of Vavilov’s scientific expeditions and ideas for development and use of legume genetic resources
• Legume Futures A major research initiative to develop novel uses for legumes in environmentally and economically sustainable cropping.