Speaking of medicinal plants, a remarkable study in Peru traces the traditional use of plants for all kinds of curative purposes from colonial times to the present. There’s an article on the work on SciDev.Net here but it is in Spanish. Although many plants used in colonial times have disappeared from the area of the study, traditional healers have replaced them with other species and have thus maintained their pharmacopeia. This is very much a living, evolvingĂ‚Â tradition.