Throughtout the literature concerning native narcotic plants of South America may be found the statement that Prestonia amazonica (Haemadyction amazonicum), an apocynaceous vine, is the basic ingredient in the hallucinogen known as yaje. But many specialists, including most field investigators, have attributed yaje to sundry species of the malpighiaceous genus Banisteriopsis. They have been in essential agreement that yaje (of the westernmost Amazon of Colombia, Ecuador and a part of Peru, especially along the eastern slope of the Andes), ayahuasca (of Peru, Bolivia and part of Ecuador) and caapi (of the northwestern Amazon of Brazil and adjacent parts of Colombia) seem to be identical narcotics prepared from malpighiaceous plants.