Erect knotweed entered the Eastern Agricultural Complex by 1000 BCE, with pits in dry rockshelters in eastern Kentucky used to store this relative of Old World buckwheat, along with other Eastern Agricultural Complex crops (Mueller 2017). Paleofecal assemblages from Salts Cave, Kentucky, provide direct evidence for consumption of knotweed by cavers between 800 and 300 BCE, although the earliest specimens showing effects of domestication date only to c. 1 BCE (Mueller 2017). In the case of knotweed, selection was in favor of larger seeds with a high proportion of smooth and thin pericarps, a process that continued throughout the first millennium CE and into the second.
Maygrass (Phalaris caroliniana) (Figure 1.2D) joined the complex during the early first millennium BCE (Fritz 2014). This early season grass, ubiquitous in human paleofeces and storage pits, occurs at many archaeological sites far north of its natural range and always associated with known cultigens including thin-testa chenopod, large sunflower, and large sumpweed seeds. Flotation at sites across the Midwest and Upland South dating to the Middle and Late Woodland periods (300 BCE to CE 900) reflects increasingly high levels of maygrass production, with large concentrations of charred seeds found in the Illinois and Ohio river valleys. By 1050 CE, farmers had carried maygrass as far north as southern Wisconsin.
Little barley (Hordeum pusillum) (Figure 1.2B), the last member of the Eastern Agricultural Complex, becomes highly visible in deposits dating to the early first millennium CE. This relative of Old World barley added early season insurance, along with maygrass, to the diets of food producers whose middens include the entire suite of these crops in greater numbers throughout the first millennium CE. Little barley’s natural range includes the whole Midwest-riverine area, so a range extension argument does not work for it as it does for maygrass, but morphological signs of domestication include naked grains no longer covered by tightly adhering glumes and wrinkled, asymmetrical grains possibly reflecting selection for three fertile florets per spikelet rather than the single floret borne by wild plants (Hunter 1992). Little barley is ubiquitous in flotation-recovered samples from Middle and Late Woodland sites in Illinois, Missouri, and Arkansas, constituting up to 40 percent of total seed assemblages (Asch and Asch 1985).
Increased commitment to the food production sector of the economy is correlated with dramatic Hopewellian earthwork building and long-distance exchange networking between 200 BCE and 400 CE, and with post-Hopewellian advances in ceramic technology. Thinner-walled pottery vessels manufactured in the Midwest after 400 CE could better withstand long-term, direct exposure to heat during the cooking of gruels and other seed-based foods (Braun 1983 ). Population growth in the region is indicated by higher site densities and either longer-term or more frequent occupations of favorable locations. Together with the archaeobotanical record for heavy dependence on native starchy and oily seed crops, Late Woodland societies (400–900 CE) are sometimes called “farmers” (Johannessen 1993; Fritz 2019). Classification schemes that relegate food producers in the North American heartland to categories below the level of farming by applying such terms as “gardening” or “horticultural” fail to appreciate the settlement patterns, demographic trends, material culture, and especially the archaeobotanical subsistence remains from sites occupied during the first millennium CE.
TOBACCO
Tobacco is not strictly a member of the Eastern Agricultural Complex because no species in the genus Nicotiana is native to this region. I mention it here, however, because tobacco was cultivated along with the native crops centuries before maize became important. Native Americans grew tobacco (Nicotiana rustica and possibly N. quadrivalvis) in eastern North America no later than 2000 years ago. Smoking pipes date to centuries earlier, but native wild plants may have been smoked before tobacco was acquired (Wagner 2000). Tobacco seeds have been recovered from three sites in Illinois dating between 100 BCE and 400 CE (Asch and Asch 1985; Simon and Parker 2006), and residues on a possibly earlier pipe from Ohio tested positively for nicotine (Rafferty 2002).
MAIZE, CUSHAW SQUASHES, AND BEANS
Many questions surround the initial acquisition—or more likely, multiple early acquisitions—of maize by Eastern Woodlands societies. Groups in the core Midwest-riverine zone were already producing pre-maize crops, whereas others incorporated maize into hunting-gathering-fishing economies that lacked earlier domesticates except bottle gourds or native pepo squash/gourds. The earliest evidence for maize is currently in the form of microbotanical remains: starch grains and phytoliths (opaline silica bodies) preserved in residues on pots dating to c. 300 BCE to 100 CE (Hart and Lovis 2012; Raviele 2011; Albert et al. 2018). These early reports come from Michigan and New York, unexpectedly far north and east for a crop that spread into eastern North America from the Southwest. Maize-like fragments from a handful of sites were believed to date to the early or middle first millennium CE, but several of these finds have been reexamined and redated: most were either not really maize or were centuries younger than expected (Adair and Drass 2011; Simon 2017). Stable carbon isotope evidence for increased maize consumption postdates 900 CE (Emerson et al. 2020).
Archaeologists have offered diverse explanations for why maize was available but did not become a staple food for so many centuries after its initial introduction (Scarry 1993; Hart and Lovis 2012; Simon 2014, 2017; Gremillion 2018). These include lack of adaptation to the new environment, lack of storability, use restricted to rituals, and farmer conservatism. What seems certain is that maize was not quickly embraced as a substantial source of carbohydrates, at least not at a scale visible in the isotopic or archaeobotanical records.
A dramatic shift occurred shortly before or after 900 CE, as reflected by high frequencies of cob and kernel fragments after that date (Simon and Parker 2006; Simon 2014, 2017). Intensification of maize did not, however, result in the abandonment of Eastern Agricultural Complex crops, particularly not in the American Bottom region of southwestern Illinois where Cahokia—the largest center north of Mesoamerica—arose quickly and dramatically after 1000 CE. With more than 100 mounds and multiple plazas in the central precinct alone and dozens more in the larger vicinity, Cahokia was an urban complex whose core area and surrounding countryside were inhabited by tens of thousands of people attracted by the rich resources of the floodplain and adjacent upland zones (Pauketat 2004, 2009; Iseminger 2010).
Massive amounts of flotation and archaeobotanical analyses in the greater American Bottom leave no doubt that Eastern Agricultural Complex crops were produced along with maize in greater quantities during the tenth, eleventh, and twelfth centuries CE (Lopinot 1994; Simon and Parker 2006; Fritz and Lopinot 2007; Fritz 2019). This strategy combined the seasonal staggering of early-season and late-season species with risk-reducing mechanisms including high agrobiodiversity and the scattering of fields across alluvial and upland landforms that vary in degree of soil moisture content and drainage capacity (Fritz 2019). Maize was a key staple at early Cahokia and became more dominant throughout the centuries of Cahokia’s occupation, but chenopod, erect knotweed, maygrass, eastern pepo squash, sunflower, and sumpweed did not disappear until after depopulation of the region at 1350–1400 CE. A new squash—the cushaw (Cucurbita argyrosperma ssp. argyrosperma), domesticated in Mesoamerica—had spread into eastern North America by 1000 CE, appearing at Cahokia both in the archaeobotanical record and on a stone figurine depicting an Earth Mother deity hoeing the body of a feline-headed serpent (Fritz 1994b).
Common beans (Phaseolus vulgaris), also domesticated in Mesoamerica and thought to have spread across the Plains via the Southwest, were latecomers to Cahokia, appearing after 1250 CE, when thousands of people had already moved away (Pauketat and Lopinot