At the end of the article there is a brief description of the global history of stories of the sharing of crops with humans by gods. It is by a different author. In the list it includes Mexico. I was under the impression that the history of corn is fundamentally different than the main crops of the 6 pristine civilizations in that it was not as ready for consumption when first encountered by humans and that it required more coaxing from a smaller form to what it became. Is this a myth? Or were wheat and rice more readily available as nutrition from the time of human discovery?