The term Eastern Agricultural Complex refers to the group of plants that originally formed the basis of agriculture in the eastern regions of North America north of Mexico. These plants included squash (Cucurbita pepo) as well as the lesser-known little barley (Hordeum pusillum), goosefoot or lambsquarter (Chenopodium berlandieri), erect knotweed (Polygonum erectum), maygrass (Phalaris caroliniana) sumpweed or marshelder (Iva annua), and sunflower (Helianthus annuus). Note that erect knotweed is a distinct species from the Japanese knotweed (Polygonum cuspidatum) that is considered an invasive species in the eastern United States today.
Of these plants, sunflower and sumpweed have edible seeds rich in oil, erect knotweed has starchy seeds, maygrass and little barley are grasses that yield grains that may be ground to make flour, and goosefoot is a leafy vegetable related to spinach. The squash that was originally part of the complex was raised for edible seeds and to produce small containers (as with gourds), not for the thick flesh that is associated with modern varieties of squash.
The agricultural record suggests humans were collecting these plants from the wild by 4000 BC, then gradually modifiying them by selective collection and cultivation over a period of centuries.
Ultimately, the societies that cultivated these plants switched over to an agriculture based on the more productive plants developed in Mexico: maize, beans and additional varieties of squash. The spread of these crops and the techniques for tending them was a slow process that took many centuries, however, as the seeds and necessary knowledge had to cross inhospitable deserts and mountains, and new varieties of plants had to be developed to suit the cooler climates and shorter growing seasons of the northern regions of the continent. So, although Mexican cultivation of maize may date back as far as 10,000 years before the present, the penetration of maize into regions dominated by the Eastern Agricultural Complex might be placed at roughly the first millennium BC, with highly productive adapted strains coming into wide use around 900 AD. It seems that maize was adopted first as a supplement to existing agricultural plants, but gradually came to predominate as its yields increased.
Displacement of most of the Eastern Agricultural Complex plants by maize-based agriculture, though a slow process, was ultimately so thorough that most of these plants are no longer under cultivation at all. Indeed, a number of them (such as little barley) are regarded as pests by modern farmers.
References
- Diamond, Jarred M. (1998). Guns, Germs, and Steel: The Fates of Human Societies. New York: W.W. Norton & Co. ISBN 0-393-31755-2
- Mann, Charles C. (2005). 1491: New Revelations of the Americas Before Columbus. New York: Random House. ISBN 1-4000-4006-X.