Man's symbiosis with plants is the most fundamental material fact of human life on the earth. Geographers, as well as botanists, anthropologists and other scientists, have long been interested in this aspect of the man-nature theme. In American geography, CARL O. SAUER emphasized a temporal as well as spatial perspective in the cultural understanding of man's relationship to biological phe­ nomena. His researches and those of his associates in the 'Berkeley school' showed that the most fruitful possibilities for implementing this approach are in non­ industrial societies which have direct and pervasive links between plants and man (GADE, 1975). The study that follows is a geography of plant resources in an important Andean valley having great environmental diversity and a cultural con­ stant, in so far as a non-literate, Quechua-speaking peasantry dominates through­ out the zone. My basic objective has been to understand the present use of plants, cultivated and wild, as they have varied from place to place and through time. Primary and secondary documents and local informants were important sources of historical information. Most of the contemporary data in this study were derived from over 20 months of empirical observations of the day-to-day existence of farming folk in their fields, homes and markets. The great natural beauty of the Vilcanota depression is matched only by the stark poverty which has been the lot of the majority of people who live there.