Article
Legume
Leguminosae, or Fabaceae, is the third-largest family of flowering plants, containing up to 650 genera and 18,000 species. Over 4,000 species are native to North America, most of which are members of the bean subfamily. They occur as scattered, secondary components of native vegetation. Over 2,000 species of milk vetch (genus Astragalus) alone occur worldwide, more than 40 in Canada. Other common native legumes are lupines (Lupinus), vetches (Vicia), locoweed (Oxytropis) and vetchling (Lathyrus). Most legumes, in association with strains of the bacterium Rhizobium,"fix" part of their nitrogen requirement and improve soils as green manure. Legumes are also a staple in the diets of both animals and humans.