Phaseolus vulgaris, the common bean, is a herbaceous annual plant domesticated in the ancient Andes, and now grown worldwide for its edible bean, popular both dry and as a green bean. The leaf is occasionally used as a leaf vegetable, and the straw is used for fodder. Beans, squash and maize constituted the "Three Sisters" that provided the foundation of Native American agriculture.
Botanically, the common bean is classified as a dicotyledon. Beans are legumes, so acquire their nitrogen through an association with rhizobia, species of nitrogen-fixing bacteria. 18.3 million tonnes of dry common beans and 6.6 million tonnes of green beans were grown worldwide in 2007.
The other major type of bean is the broad bean (Vicia faba), of which 3.7 million tonnes were grown in 2007. The commercial production of beans is well-distributed worldwide, with countries in Asia, Africa, Europe, Oceania, South and North America all among the top bean growers. Brazil and India are the largest producers of dry beans while China produces, by far, the largest quantity of green beans, almost as much as the rest of the top ten growers combined.