At European contact, Native American agriculturalists in both eastern North America and Middle America (Mexico and Central
America) relied primarily on a group of three crops: maize, squash, and beans. The widespread geographical occurrence of this
agrarian triad in historical times would seem to suggest its considerable antiquity in the New World. While archaeological
investigation indicates that each of the crops was domesticated in the Americas thousands of years ago, it also indicates
that times of domestication and times of diffusion were substantially different for each (Smith 2001). This study presents
linguistic evidence bearing on the prehistoric chronology of one of these crops, the common bean (Phaseolus vulgaris L.).
The common bean (hereafter bean) was domesticated in two New World regions, Mesoamerica and the Andes (Gepts 1998). The earliest
date for cultivated beans in the Americas is around 4400 years BP (before present) (Kaplan and Lynch 1999:269). This date
was determined through use of accelerator mass spectrometry (AMS) applied to an archaeological bean specimen recovered from
Guitarrero Cave in Andean Peru.
AMS has produced a definitive bean chronology for at least one area of the New World. It is now decisively determined that
in the northern Eastern Woodlands of North America beans became a significant part of the Amerindian diet beginning around
700 years BP (Hart and Scarry 1999, Hart et al. 2002). For various reasons, definitive bean chronologies are yet to be determined
for other New World regions.