Aboriginal specialty-plant propagation: Illinois prehistory and an eastern North American post-contact perspective.

Abstract

The west-central Illinois archaeological record detailed in this dissertation provides evidence for prehistoric propagation of 3 or 4 specialty plants (i.e., plants used primarily for nonfood purposes or, if foods, eaten primarily for reasons other than a contribution to caloric requirements). One, a gourd form of Cucurbita pepo, probably was the first plant grown there--at least 7000 years ago. Others are bottle gourd (Lagenaria siceraria), tobacco (Nicotiana sp.), and possibly common sunflower (Helianthus annuus). Morphological evidence of domestication is lacking for the oldest records; assertions that the remains reflect agricultural activity is controversial. According to some current hypotheses, these plants grew in Illinois prehistorically as indigenous wild species or weedy campfollowers. However, phytogeographic and other botanical evidence best support an interpretation that they were nonpersistent exotics whose presence therefore is ipso facto evidence that they were grown. Were these exotics just the readily recognizable members of a larger group of specialty plants grown in the past--largely invisible because it consisted of indigenous species that lacked morphological signs of domestication, that are poorly preserved, or that were grown and used sparingly? Aboriginal specialty-plant propagation in eastern North America during historic times provides a useful perspective for thinking about what is missing in the prehistoric record. Planting of 22 species was documented in a comprehensive and critical review of historic records. In general, decisions to grow them were expedient; there was no consistent pattern to their propagation across eastern United States. All but one are perennial, and they were primarily medicinal. Considered in relation to these historic specialty plants, the distinctiveness of gourds, tobacco, and sunflower clearly is not just due to ease of recognition as having been propagated. The latter belong to a small set of plants whose remarkable potential cultural uses and biological characteristics made it possible for them easily to cross cultural and ecological boundaries as intentionally propagated species--even before significant domesticatory modification occurred. Specialty-plant agriculture arose and developed in prehistoric Illinois largely through external contacts, not by autochthonous development of indigenous species.