The paper summerizes what is currently known about the cultivation, preparation, and effects of psychotropic beverrages based on Banisteriopsis. The number of classes of Yagé recognized by the Siona, a Western Tukanoan group living along the Putumayo river where it divides Colombia from Ecuador, exceeds the few plant species identified by western botanists. The discriminating features used in native identification are more complex than those of scientific botany and more dependent upon context. The native classes of yagé are based on a conjunction of botanical features, preparation, visionary effects, and the history of the vine used. This paper points to an important area of research that warrants further investigations, the effects of culture in hallucinogenic visions and the role of visions in native plant classification.