Phaseolus lunatus is a legume. It is grown for its seed, which is eaten as a vegetable. It is commonly known as the lima bean or butter bean.
Phaseolus lunatus is of Andean

Andes

The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...

 and Mesoamerica

Mesoamerica

Mesoamerica is a region and culture area in the Americas, extending approximately from central Mexico to Belize, Guatemala, El Salvador, Honduras, Nicaragua, and Costa Rica, within which a number of pre-Columbian societies flourished before the Spanish colonization of the Americas in the 15th and...

n origin. Two separate domestication

Domestication

Domestication or taming is the process whereby a population of animals or plants, through a process of selection, becomes accustomed to human provision and control. In the Convention on Biological Diversity a domesticated species is defined as a 'species in which the evolutionary process has been...

 events are believed to have occurred. The first, taking place in the Andes around 2000 BC, produced a large-seeded variety (Lima type), while the second, taking place in Mesoamerica around AD 800, produced a small-seeded variety (Sieva type).