Evidence for variability among squash seeds from the Hoxie site (11CK4), Illinois

Uncarbonized Cucurbita pepo L. (squash) seed coats were recovered from the base of a fortification ditch in water-saturated contexts at the Hoxie Farm site (11CK4) in northeastern Illinois. A direct date on one specimen indicated association with the Huber phase occupation, or about 1600 A.D. Sizes were highly variable, suggesting the presence of two or more squash varieties. To explore that possibility, length and width measurements were obtained for 21 specimens. A simple hierarchical cluster analysis revealed the presence of three distinct seed size groups. The two smaller conform to sizes displayed by modern varieties of subspecies ovifera which is the type domesticated in North America. Sizes for the third group of large seeds fall outside the range of any modern subspecies ovifera and within the range for the Mexican domesticate subspecies pepo. Similar large sized seeds first appear in the archaeological record from the Midwest during the Late Mississippian times. The potential for long-term prehistoric cultivation of two distinct lineages in the Midwest, and problems inherent in the scenario are discussed.

► Provides a numerical analysis of Cucurbita pepo seeds recovered from an archaeological site in northern Illinois, USA.
► Defines three groups based on seed sizes.
► Compares seed size groups to sizes from modern varieties and archaeological collections.
► Discusses implications in terms of introduced Mesoamerican cultivated subspecies and native cultivated subspecies.
► Addressed questions of hybridization and speciation in Eastern North America.