Phaseolus is a genus of about 50 species in the Faboideae (syn. Papilionoideae) subfamily of the Fabaceae (syn. Leguminosae) family native to the Americas. Some of the species are cultivated for food (beans).
Phaseolus coccineus, commonly known in English as runner bean, differs from the common bean (Phaseolus vulgaris) in that the cotyledons stay in the ground during germination and the plant is perennial with tuberous roots (though it is usually treated as an annual). The pods can be eaten when young and the seeds can be used fresh or as dried beans. The starchy roots are still eaten by Central American Indians. And it is commonly grown for its red and/or white flowers. It is native to Mexico and Guatemala. Photographed by David Pilling. In the picture of the root, the nitrogen fixing nodules characteristic of Fabaceae can be seen at the top; these are home to symbiotic bacteria Rhizobia.