(approaching, in some respects, P. amazonica) or a re- 
lated apocynaceous genus. 
In 1922, the Belgian horticulturist-explorer Claes (1,2 
studied yaje amongst the Koregwahe Indians of the Co- 
misaria del Caqueta in Colombia. He learned that the 
yaje, hitherto usually described as a ‘‘small bush’’ was 
an enormous forest liana, and he argued quite justifiably 
that those who had described it as a small bush had seen 
only young, cultivated individuals and not the vine in its 
wild state. Claes did not offer a botanical determination 
of yaje. He mentioned, however, that the Belgian bota- 
nist De Wildeman believed that it ‘‘might be’? Pres- 
tonia amazonica. This would be most unusual, since, so 
far as we know, Prestonia amazonica does not become an 
enormous jungle liana. No voucher specimens were lo- 
cated in the Rijksplantentuin in Brussels, and Claes him- 
self stated that he had not obtained material for identify- 
ing yaje. With this statement, we must assume that De 
W ildeman was voicing an opinion which he based on the 
information he was able to glean in the literature through 
the use of the vernacular name. 
The pharmacologists Michiels and Clinquart (17) 
worked on the stems which Claes had collected. In 
1926, they suggested—whether from their own observa- 
tions or from the opinions of De Wildeman we do not 
know—that the stems appeared to belong to Prestonia 
amazonica. The same year saw the French pharmacolo- 
gist Rouhier dismiss as ‘‘doubtful’’ the possibility that 
yaje could be referable to Prestonia amazonica. 
In 1980, the French botanist Gagnepain (7) tried 
rather unsuccessfully to put some order into the chaos. 
He pointed out that 1) according to Reinberg, ayahuasca 
was ‘‘probably”’ Banisteriopsis Caapi but that yaje could 
not be referred to this species ; 2) yaje seemed to approach 
Prestonia amazonica; 8) fragments received as yaje by 
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