Submitted by Sammy Smith (firstname.lastname@example.org)
After abandonment, the remains that people leave behind that are out in the open and exposed to weather are strongly affected by that exposure. Rain and sun, for example, promote decomposition of organic remains. This means that food remains tend to degrade and disappear. One type of food remains that does more commonly survive under special conditions are charred seeds, nutshells, wood, and the like.
However, chemical indications of foodstuffs may survive.
Archaeologists working in Mesoamerica have been testing pottery for evidence of food with cacao—the fruit of Theobroma cacao trees, which we use today to make chocolate. Scientists can identify the presence of cacao residue because it has distinctive chemistry, including theobromine.
Early Euro-American travelers in Southeastern North America noted that some Native peoples used a special tea, commonly called Black Drink or cassina today, in purification rituals.
Black drink is made from an evergreen shrub with the scientific name Ilex vomitoria, and referred to as yaupon holly. Consuming copious amounts of or strongly brewed black drink induced vomiting, hence the scientific name given to the shrub.
Realizing that yaupon holly, like cacao, has distinctive biomarkers—including methylxanthines such as theobromine, caffeine, and ursolic acid—researchers working with ceramics from Cahokia tested the chemical makeup of deposits on the interior of small mugs or cups (which archaeologists often call beakers). Cahokia is a famous Mississippian-period civic-ceremonial and residential site (that was settled in Late Woodland times) with hundreds of mounds and numerous plazas across the Mississippi River from present-day St. Louis, Missouri.
The chemical profiles researchers Patricia L. Crown, Thomas E. Emerson, Jiyan Gu, W. Jeffrey Hurst, Timothy R. Pauketat, and Timothy Ward identified matched those of Ilex vomitoria and a related species of holly, Ilex cassine or Dahoon holly.
So, the research has confirmed that Ilex was used by Native peoples as far back as the Lohmann phase, AD 1050–1100, at Cahokia.
There’s an additional implication of this research.
These two species of Ilex do not grow near Cahokia, and did not in Mississippian times. While Native peoples may have transplanted specimens to Cahokia, Crown et al. argue that the Ilex was instead traded over established trade routes from areas along the Gulf Coast where it is a native plant. The authors note:
It appears then that when Cahokians imbibed Black Drink, it was an imported luxury. If Black Drink were as intimately interwoven into the spiritual and political life of Cahokians as it was among historic natives in the Southeast, they would have required large amounts of Ilex. Such an exchange network would have connected Cahokians to groups who had access to holly, such as their Caddoan neighbors in the Arkansas River valley or groups near the mouth of the Mississippi River.
Points to consider: How important must the Ilex tea have been to Cahokians to trade for it from sources some 250 miles—or more—distant? Compare the trade in Ilex for tea-making to trade in khat, which has leaves that are chewed for their stimulant effects by peoples native to northeast Africa, and by expatriates from those regions.