Common bean
Family Leguminosae: Papilionaceae (or Fabaceae)
Phaseolus vulgaris, the common bean (P. vulgaris 1), is an erect or twining annual herb, showing considerable variation in habit, vegetative characters, and size, shape and colour of pods and seeds.
A usual division is into dwarf or bush forms (Phaseolus vulgaris var. nanus) (P. vulgaris 2), and climbing or pole forms (Phaseolus vulgaris var. vulgaris) (P. vulgaris 3). The first group being 20-60 cm high, the second 2-3 m high. The leaves are always alternate, trifoliate; the flowers, borne in axillary clusters, are white, yellowish, pink or purple. The pods are 8-12 cm long, usually with 4-6 seeds, straight or slightly curved. The seeds are very variable in size, shape and colour: white, yellow, green, pink, red, purple, brown and black; plain, mottled or blotched. In the temperate regions common beans are cultivated in the open and in greenhouses (P. vulgaris 4).
Distribution
The common bean is of New World origin and was known to the Aztecs. It was taken to Europe in the 16th century and is now widely cultivated in many parts of the tropics, subtropics and temperate regions. Common beans are grown for the edible pods and the dry ripe seeds. In Latin America they provide a large part of the protein food, of which they contain an average of 22%. In Europe and the US common beans are a very important vegetable and are also canned and frozen in large quantities. They are little grown in India.
Use
The many varieties of common beans can be divided into the following main groups:
1. Dry-shell or field beans, which are grown for the dry ripe seeds (P. vulgaris 5). They include pea or navy beans, red kidney beans and marrow beans.
2. Snap beans grown for their pods, which are harvested before they are fully ripe (P. vulgaris 6). As fresh vegetables, flat or oval pods are preferred; for canning more forms with rounder pods are used. For slicing French beans with flat pods are used (P. vulgaris 7).