Flowers are irregular, bilaterally symmetrical, usually 10 stamens, one pistil of two carpels. No endosperm at maturity. D. Nitrogen fixation was discovered in legumes, due to symbiotic association of Rhizobium species of bacteria that inhabit nodules on roots. Today, strains of Rhizobium are sold to enhance agricultural productivity and is the subject of considerable research . In fact, some cultivars have been developed with the bacterium as a requirement.
Common beans are native to Mexico and the Andes .
Beans are not the only food that causes flatulence . Garden pea is native to Near East. Rich in protein, carbohydrate. Immature pod also eaten, as snow peas or sugar snap peas. Peas were subject of Mendel's investigations of genetics.