Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Electron micrograph of a burned sweet potato (Ipomoea batatas). Characteristically in sweet potato roots, the tissue organization is disrupted by the formation of radially oriented cavities (as seen in this image) when carbonized (16). This sample from Middle Preclassic Tikal represents the first evidence for sweet potato in the ancient Maya Lowlands. It was accelerator mass spectrometry radiocarbon dated to cal 640 ± 30 B.C. (SD).
