Chenopodium berlandieri Moq. ssp. jonesianum

Chenopod (goosefoot; lambsquarter)

Chenopodiaceae
       This small, nutritious seed (properly called a fruit because the pericarp--the thin papery fruit coat--is present) is common in many archaeobotanical samples. Chenopod is part of the pre-maize quartet of starchy crop seeds, including maygrass, little barley, and erect knotweed. Other chenopod species can be represented in samples, but I will touch only on the domesticated sub-species and its closest relatives.

Description
       Chenopod seeds are relatively easy to identify. Their embryos wrap around the seed and overlap, causing each seed to have a little "beak" (Figure 1). However, the embryo is often missing in charred archaeological specimens because the heat during charring may cause the seed to pop. A popped chenopod seed looks like a tiny hamburger, with the puffed-up perisperm pushing the halves of the seed coat testa away from each other (Figures 4 and 5). 

       Charring may also cause the loss of the pericarp. The retention of this reticulated (net-like) covering is important if one is to identify a charred, formerly black chenopod (Figure 4) from a charred, formerly pale chenopod (Figure 5). The testa of the former is stiff enough so that it can stand away from the perisperm on its own, while the latter's cannot. Measurements of the testa thickness of the thin black morph (shape variant) range from 10 to 22 µm.  Studies regarding the thickness of the pale morph testa have not been performed. Seed sizes average about 1.4 or 1.5 mm in diameter.
       Chenopod seeds can be confused with amaranth (pigweed--Amaranthus sp.) seeds, because they also have embryos that wrap around to form little "beaks." Often, an analyst creates a category called "cheno-am" to deal with ambiguous specimens. Chenopod has also been confused with pokeweed (Phytolacca americana) in the past (Asch and Asch 1977). Careful study of size and testa texture is required in these cases.

Archaeological Distribution
       Archaeological C. berlandieri has been found throughout the Midwest and Southeast, including Missouri, Illinois, Kentucky, Tennessee, Ohio, Arkansas, and Alabama (Fritz 1990).
       It is hypothesized that the wild type of chenopod, C. berlandieri, was being cultivated as early as 4000 BP (Asch and Asch 1985). With cultivation came morphological changes in the seed itself. The cultivated morph has a thin, black testa and is called C. berlandieri ssp. jonesianum. It is found after 3500-3000 BP, especially in rockshelters, under desiccated conditions (Smith and Cowan 1987). A pale testa variety of C. berlandieri ssp. jonesianum has been found in contexts dating to after 2500 BP (Fritz 1990; Wilson 1981).

The Modern Plant and Its Distribution
       Chenopod plants are annuals with slender branches. The plant can attain variable heights: from waist level to over one's head (when growing in the most favorable conditions). The leaves are 2-4 cm long, and lance-shaped. Flowers and fruits are concentrated at the ends of the branches. 
       Most modern chenopod plants found in weedy places, such as empty lots, railroads, and roadsides, are either C. missouriensis, C. album (an introduced species), or possibly C. belandieri. C. berlandieri (Figure 6) can occasionally be found in disturbed fields and well-drained floodplains (Smith 1992a), along with other disturbance-loving annuals, such as sumpweed, knotweed, giant ragweed, and sunflower. C. berlandieri is found all over the Southeast, and north to Missouri, Indiana, Illinois, Michigan, and Pennsylvania.

Taxonomic Problems
       Chenopodium album is a very common modern weed, but the plants have seeds without reticulated (net-like) pericarps as most well-preserved archaeological specimens do.  C. missouriensis is a native chenopod common in the middle Mississippi River Valley, but its seeds do not have reticulated pericarps either. C. bushianum is a native species whose seeds are slightly larger than those of C. berlandieri. C. bushianum and C. berlandieri live in similar habitats, their populations grade into each other, and their hybrids are fertile. Both of these species have seeds with reticulated pericarps.  Paleoethnobotanists use the name C. berlandieri to describe archaeological chenopod, subsuming both C. berlandieri and C. bushianum (D. Asch and N. Asch 1985). The thin-testa morph was formally designated C. berlandieri ssp. jonesianum by Smith and Funk (1985).

Discussion
       The question of the location of chenopod domestication is an interesting topic in the literature. The range of possibilities is discussed by Smith (1992b). It should also be noted that chenopod genera are also used medicinally and as potherbs.

References
Asch, D. L., and N. B. Asch
    1977   Chenopod as Cultigen: A Re-evaluation of Some Prehistoric Collections from Eastern North
            America. Midcontinental Journal of Archaeology 2:3-45.
    1985   Prehistoric Plant Cultivation in West-Central Illinois. In Prehistoric Food Production in North
            America, edited by R. I. Ford, pp. 149-203. Anthropological Papers No.75. Museum of
            Anthropology, University of Michigan, Ann Arbor.
Fritz, G. J.
    1990   Multiple Pathways to Farming in Precontact Eastern North America. Journal of World
            Prehistory 4:387-435.
Kindscher, K.
    1987   Edible Wild Plants of the Prairie. University Press of Kansas, Lawrence.

Smith, B. D.
    1992a  The Economic Potential of Chenopodium berlandieri in Prehistoric Eastern North America. In
            Rivers of Change: Essays on Early Agriculture in Eastern North America, edited by B. D. Smith,
            pp. 163-183.  Smithsonian Institution Press, Washington, D.C.
    1992b  The Role of Chenopodium as a Domesticate in Premaize Garden Systems of the Eastern
            United States. In Rivers of Change: Essays on Early Agriculture in Eastern North America,
            edited by B. D. Smith, pp. 103-131. Smithsonian Institution Press, Washington, D.C.
Smith B. D., and C. W. Cowan
    1987   Domesticated Chenopodium in Prehistoric Eastern North America: New Accelerator Dates
            from Eastern Kentucky. American Antiquity 52:355-357.
Smith, B. D., and V. A. Funk
    1985   A Newly Described Subfossil Cultivar of Chenopodium (Chenopodiaceae). Phytologia
            57:584-587.
Wilson, H. D.
    1981   Domesticated Chenopodium of the Ozark Bluff Dwellers. Economic Botany 35:233-239.

Written by: Gina S. Powell