i 
BOTANICAL MUSEUM LEAFLETS 
HARVARD UNIVERSITY 
VoL. 10, No. 1 
CamsBripGr, Massacuusetts, Ocroper 30, 1942 
PLANTAE COLOMBIANAE II 
BY 
Ricuarp Evans SCHULTES 
YOCO: A STIMULANT OF SOUTHERN COLOMBIA 
THE NUMBER OF SPECIES used as narcotics and stimu- 
lants by the Indians of Middle and South America is 
comparatively small. Nevertheless, the botanical source 
of several, until recently, has remained doubtful or un- 
known. During the last twenty-five years, extensive re- 
search in the identification of narcotics and stimulants has 
been carried out. Asa result, at the present time, nearly 
all of the species which are used have been identified. 
One of the few important exceptions is the remarkable 
yoco Which has long been employed as a stimulant by the 
Indians of a small part of southern Colombia and the 
adjacent regions of Ecuador and Peru. 
During the course of ethnobotanical studies in the 
Putumayo, Colombia,’ in 1941 and 1942, I found that 
the most important non-alimentary plant in the economy 
of the natives of the tropical areas is yoco. The flowering 
of the yoco plant—an extensively climbing liana—is ap- 
parently sporadic and capricious, and it was possible to 
collect fertile material only after months of search. Infre- 
quency of flowering is probably one of the reasons for the 
neglect by botanists of this important economic plant. 
‘*Plantae Colombianae I’’ was published in Caldasia 1 (1942) 19-24. 
1Carried out under the auspices of the National Research Council, 
Washington, D.C. 
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