Legume

A legume is a plant in the family Fabaceae (or Leguminosae), or a fruit of these plants. A legume fruit is a simple dry fruit which 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 pod is also applied to a few other fruit types. Well-known legumes include alfalfa, clover, peas, beans, lentils, lupins and peanuts. A peanut is not a nut in the botanical sense; a peanut is an indehiscent legume, that is, one whose pod does not split open on its own.

The history of legumes is tied in closely with that of human civilization, appearing early in Asia, the Americas (the common bean, several varieties) and Europe (broad beans) by 6,000 BC, where they became a staple, essential for supplementing protein where there was not enough meat.

Legume plants are noteworthy for their ability to fix atmospheric nitrogen, an accomplishment attributable to a symbiotic relationship with certain bacteria known as rhizobia found in root nodules of these plants. The ability to form this symbiosis reduces fertilizer costs for farmers and gardeners who grow legumes, and means that legumes can be used in a crop rotation to replenish soil that has been depleted of nitrogen.

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

Farmed legumes can belong to numerous classes including forage, grain, blooms, pharmaceutical/industrial, fallow/green manure and timber species, with most commercially farmed species filling two or more roles simultaneously.

The term is derived from the French word "légume" which, however, has a wider meaning and refers to any kind of vegetable; the English word legume being translated in French by the word légumineuse.

Legumes are a good source of iron and fiber. citation needed]