Then there arose, primarily from uncritical interpretation of 
Spruce’s field notes, an extraordinary presumption that gained 
very wide acceptance in the literature: it presumed that, al- 
though ayahuasca and caapi were derived from Banisteriopsis, 
yajé referred to the apocynaceous Prestonia amazonica 
(Benth.) Macbr. Although this suggestion has been thoroughly 
discredited (Schultes and Raffauf, 1960), it persists in the popu- 
lar and, unfortunately, even in the technical literature. It is 
responsible for much of the confusion in chemical and phar- 
macological studies. Spruce, in his field notes, suggested that 
the Indians of the Vaupés sometimes added a plant, which he 
felt might have been what the Indians called caapi-pinima 
(‘painted caapi’’): he noted that it looked like the apocynace- 
ous plant that he had collected earlier in the central Amazon 
and which was described as a new species: Haemadictyon 
amazonicum Benth. ex Muell.-Arg., now known as Prestonia 
amazonica (Spruce, 1908). This tentative observation was later 
uncritically interpreted by a French researcher who had never 
been in the field as a flat assertion and was so published 
(Reinberg, 1921). Prestonia amazonica, collected but once in 
over 125 years, is known only froma locality nearly 1500 miles 
from the Uaupés; with all of the now known admixtures used 
with the drink, there is no question that the local additive to 
which Spruce referred could not have been Prestonia amazon- 
ica, especially since so many botanists and ethnologists have 
worked in the region where Spruce collected and have not 
found a species of Prestonia employed for this hallucinogenic 
purpose. 
It is now definitely known that the major constituents of 
ayahuasca, caapi and yajé are species of Banisteriopsis. There 
remains, however, the colossal task of elucidating the many 
additives which Amazonian Indians put with the hallucinogen 
(Schultes, 1972). These additives or admixtures may be very 
localized — even to a single medicine man — or they may be 
widely utilized. There is, in many instances, good reason to 
assume that they drastically alter or strengthen the effects of B. 
Caapi or B. inebrians alone. 
The Siona of Colombia add what is probably Brugmansia 
suaveolens (H. et B. ex Willd.) Bercht. et Presl., in itself an 
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