Old World plants in Andean healing, and the colonial survey that lets it be measured

The plant traffic between Spain and the Andes ran both ways. Surveys of the medicinal plants sold and used today in northern Peru and southern Ecuador find 17% of them to be Old World introductions, many carried in during the colonial centuries, and a bishop's eighteenth-century inventory is still the baseline against which two hundred years of change is counted. The same surveys record the cost: healers persecuted, and traditional medicine illegal in Ecuador until 1998.