Native N American crops
Max Withers (Thu, 18 Mar 2010 19:55:01 PDT)

The only "major" crop plant native north of the Rio Grande is commonly
reckoned to be sunflower, Helianthus annuus. One could add Jerusalem
artichoke (Helianthus tuberosus), wild rice (Zizania spp.), and various
berries, but the list is not long.

Maize is not thought to have been introduced to the Mississippi valley until
c. 600 CE, despite having been domesticated some 8000 years previously; the
difficulty was selecting for day-length appropriate taxa for the move away
from the equator. (Conversely, Eurasian crops easily moved many times that
distance, but remained within the same latitudes).

For this reason, I think Jim's maintenance of a Mesoamerican bioregion makes
sense here.

This post is not off topic because it mentions H. tuberosus,
Max
Oakland CA