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 > Message: 13 > Date: Thu, 18 Mar 2010 21:41:06 -0400 > From: "Jim McKenney" <jimmckenney@jimmckenney.com> > Subject: Re: [pbs] Native N American crops > To: "'Pacific Bulb Society'" <pbs@lists.ibiblio.org> > Message-ID: <6FCE6BF68FB44DDD81C5574016E506A8@Library> > Content-Type: text/plain; charset="iso-8859-1" > > Well Leo and Alberto, I think the answer to this one depends on how you > divide up the Americas! > >