The generic name Phaseolus was introduced by Linnaeus in 1753, borrowed from the Latinphaseolus a combination of phas?lus and the diminutive suffix-olus, in turn borrowed from Greek ? 'cowpea'. This term is often incorrectly glossed as 'kidney bean', a New World crop, but the word's ultimate origin of is unknown.
Previous classifications placed a number of other well-known legume species in this genus, but they were subsequently reassigned to the genus Vigna, sometimes necessitating a change of species name. For example, older literature refers to the mung bean as Phaseolus aureus, whereas more modern sources classify it as Vigna radiata. Similarly, the snail bean Vigna caracalla was discovered in 1753 and in 1970 moved from Phaseolus to Vigna. The modern understanding of Phaseolus indicates a genus endemic only to the New World.
Species have been organized into eight groups based on phylogenetic clades:
^Rosales-Serna, R.; Hernández-Delgado, S.; González-Paz, M.; Acosta-Gallegos, J. A.; Mayek-Pérez, N. (2005). "Genetic Relationships and Diversity Revealed by AFLP Markers in Mexican Common Bean Bred Cultivars". Crop Science. 45 (5): 1951. doi:10.2135/cropsci2004.0582.