Charred, non-maize seed concentrations in the American bottom area: Examples from the Westpark site (11-MO-96), Monroe County, Illinois

Midcontinental Journal of Archaeology, Spring 2000 by Powell, Gina S

ABSTRACT

Analysis of charred seed concentrations from the Westpark site (11-MO-96), in the American Bottom, Illinois, contributes to the understanding of the domesticated status and deposition patterns of sunflower (Helianthus annuus var. macrocarpus) and chenopod (Chenopodium berlandieri var. jonesianum) during the Late Woodland Patrick phase and of erect knotweed (Polygonum erectum) during the Emergent Mississippian Dohack phase. For the Patrick phase, the sunflower seeds are the expected size, but the large sample reveals the unreliability of the standard achene size correction formula. One or possibly two types of domesticated chenopod were used at the site during the Patrick phase. The placement of a later seed concentration in the center of an Emergent Mississippian Dohack phase community at the site suggests a public or ceremonial component to seed deposition. In addition, seed concentrations from other sites and time periods in the American Bottom area show that seed concentration deposits seem to be segregated by taxon or by season of harvest.

Quantification of paleoethnobotanical data has helped archaeologists recognize plant-use strategies by prehistoric people in the American Bottom region of Illinois (Johannessen 1984a; Parker 1991). Statistics such as seed-to-nut and seedper-liter ratios have led to the recognition of patterns regarding the decline of nut use during the Late Archaic period and the increase in the consumption of starchy seeds during the Late Woodland period. However, seed concentrations usually are not included in tabulations because they are thought to skew the quantified trends derived from soil samples.

Although not used in standard quantifications, data from seed concentrations can provide useful information for addressing issues such as intrapopulation variability and harvesting, preparation, and storage techniques. Such information, plus evidence for the timing of native plant domestication, has been derived from concentrations in dry caves in the Ozarks, Kentucky, and Tennessee (e.g., Fritz 1984, 1986, 1994, 1997; Smith 1984, 1985), but can be considerably more difficult to obtain from charred seeds from open sites. Yet charred seed concentrations are fairly common. Charring resulting in seed concentrations at open sites could conceivably occur during one of several stages of processing, storage, or disposal:

1. while parching seeds to dry them and prevent germination,

2. during storage due to accidental exposure to fire or spontaneous combustion,

3. purposeful burning to dispose of spoiled stores and to clean a pit for possible subsequent use, or

4. use of an old storage pit containing leftover seeds as an earth oven or as a dump where coals or hot ashes are disposed.

In this article, data from two Late Woodland and four Emergent Mississippian charred seed concentrations from the Westpark site, Illinois, will be presented to document the morphological characteristics of domestication, intrapopulation variability, and the possible depositional contexts of the concentrations. Descriptions and measurements of botanical remains in the concentrations are presented, and seed concentrations from nearby sites are discussed in order to try to define possible patterns in seed deposition.

The Westpark Site

The Westpark site (11-MO-96) is a multicomponent site in the uplands of the American Bottom area (Figures 1-3). It is located approximately 30 km southeast of St. Louis on the western city limits of Columbia, Illinois. When construction projects threatened the site, it was salvaged by volunteers and the Central Mississippi Valley Archaeological Research Institute under the direction of John Kelly in 1986 and 1989. Mechanical scrapers removed the plowzone, exposing prehistoric features. Of the estimated 3,000 features originally present, over 200 were mapped and excavated (Lopinot et al. 1991). This article focuses on the six features that contained seed concentrations, two from the Late Woodland Patrick phase (A.D. 600-800, uncalibrated; Powell 1993), and four from the Emergent Mississippian Dohack phase (A.D. 800-850, uncalibrated; Lopinot et al. 1991). Patrick phase Features 166 and 167, containing thousands of chenopod and hundreds of sunflower remains, were located on a bluff spur south of the Dohack phase community (Figure 4; Table 1). Feature 326 was one of four pits situated in the center courtyard of the Dohack phase community, and the other analyzed Dohack phase features (300, 597, and 631) were scattered over the site. Each of these Dohack phase features contained thousands of erect knotweed (Polygonum erectum) seeds.

Feature 166 was bell shaped (Figure 5), approximately 1.3 m wide at its base and about 55 cm deep from the surface after the plowzone was removed. It might have served as a storage pit and subsequently as a trash pit. A zone of burned botanical material, where the seed concentration was found, occurred at the base of the feature, possibly the result of a single storage or parching accident. Feature 167 (Figure 6) was located on the west edge of the bluff, adjacent to Feature 166, and was partially eroded. This feature might represent the base of an earth oven about 1 m wide and comparable in size and depth to Feature 166. In the plan map, excavators noted a zone of burned thatch, heavy concentrations of charcoal, and a concentration of sunflower seeds, from which the flotation sample probably was taken. Like Feature 166, Feature 167 might have been dug initially as a storage pit, then used as an earth oven, and then as a trash receptacle, with the seeds found at the bottom resulting from a single storage or parching accident.