Legumes

Basic Information

This site tells the story of the history of the universe. Click Earlier and Later to follow the story. Note: Many facts have been simplified to make them easier to understand.

A legume is the pod of a plant such as peas, beans or vetches, which all belong to the same family of plants (Leguminosae, or Fabaceae). Legumes provide an vital source of food for humans and their animals. They are high in protein and contain many of the essential amino acids. People get protein from peas, beans, peanuts and soybeans while their animals get it from alfalfa (lucerne) and clovers, which is then passed on to the humans when they eat their animals.

Legumes get the nitrogen they need to make these amino acids from symbiotic Rhizobium bacteria which live in nodules on their roots. These bacteria are able to fix nitrogen, transforming atmospheric nitrogen into nitrates and other compounds, some of which are passed on the the legume. In return the legume gives protection and food to the bacteria. These compounds are also available to other plants after decayed roots (and other plant parts) of the legume have released these nitrogen products into the soil. Animals get nitrogen compounds by eating plants.

We also extract edible oils, fibers, and raw material for plastics from them.

There are about 18,000 species, common ones include

broad bean or fava bean (Vicia faba) is native in northern Africa and southwest Asia. It was the major bean of antiquity and is still used for cover, green manure, and forage
mesquite (Prosopis) in southwestern United States
honey locust (Gleditsia triacanthos) in eastern North America
Kentucky coffee tree (Gymnocladus dioica) in eastern North America
wattle (Acacia) in Australia
the herb Neptunia oleracea grown underwater in India
there are about 1,200 species of Acacia found in deserts and savannas of subtropical regions
around 400 species of Mimosa in the same areas
among the most exotic trees and shrubs in the tropics are the 500 or so species of Cassia in eastern North America, northeast Africa, and India. The leaves of some are laxative and are cultivated for medicinal use while others are grown as ornamental plants or for their timber or firewood
peanuts or groundnuts (Arachis hypogaea) support the economies of many nations in temperate and tropical regions
as too do soybeans (Glycine max)
alfalfa provide animal fodder
as do red clover (Trifolium) and white clover (Melilotus)
also vetches (Vicia species)
and cowpeas (Vigna species).
kidney beans (Phaseolus vulgaris) originated in Central America, as too did
snap beans
green beans
pinto beans
sieva bean (Phaseolus lunatus)
lima bean (Phaseolus limensis)
scarlet runner bean (Phaseolus coccineus)
locoweed are some species of Astragalus poisonous to livestock on the prairies of the central United States

Seeds of the Phaseolus beans and other legumes produce phytohemagglutinin, a protein that clots certain human blood types and has other medical applications.

Like this web site? Buy the book!

Biological Environment > Legumes

Basic Information