SEM micrographs of seeds from four tobaccos historically cultivated by aboriginal groups in the eastern woodlands and adjacent Great Plains of North America are presented. The tobaccos considered are <i>Nicotiana rustica</i>, <i>N. attenuata</i> Torr., <i>N. bigelovii</i> var. <i>quadrivalvis</i> (Pursh) East, and <i>N. bigelovii</i> var. <i>multivalvis</i> (Lindley) East. Micrographs of seeds from herbarium collections are compared with micrographs of carbonized tobacco seeds from the extended Middle Missouri component at the Travis I site, and tobacco is reported from the Dirt Lodge Village site, both in South Dakota. The archaeological specimens compare most favorably with <i>N. bigelovii</i> var. <i>quadrivalvis</i> (Pursh) East, the tobacco historically cultivated by the Arikara, Mandan, and Hidatsa. These results strengthen the evidence for trade contacts and cultural interaction by Middle Missouri tradition populations with groups to the west and provide new data on the temporal perspective for the cultivation of <i>N bigelovii</i> var. <i>quadrivalvis</i> (Pursh) East in the Middle Missouri subarea.