Getting to the roots of tubers

摘要

Starch, derived from the roots of tuberous plants, is the staple dietary energy resource for the peoples of many tropical countries. These plants, such as manioc (or cassava, Manihot esculenta, Fig. 1) and sweet potato (Ipomoea batatas), are widely used, yet little is known about their origins. Undoubtedly they evolved in Central and South America, but beyond that there is little evidence of where or when they were first brought into cultivation. The main problem for archaeologists is the lack of fossils — unlike the grasses, tuberous plants have no persistent parts that survive in sites of former cultivation or food preparation. But an approach that may open up new opportunities for tracing the roots of Neotropical agriculture is now reported in the Journal of Archaeology. Dolores Piperno and Irene Hoist show that starch grains belonging to some of the plants in question have survived on the surfaces of prehistoric stone tools.