PITCH-YIELDING TREES OF THE 
COLOMBIAN AMAZONIA 
BY 
RicuHarp Evans ScHULTES 
WHILE in the northwest Amazon, I was repeatedly im- 
pressed by the important role which various resinous 
pitches play in the daily lives of the Indians of the area. 
A study of some of the trees which are most commonly 
used as sources of pitch has not only yielded interesting 
ethnobotanical data but has also brought to light several 
apparently hitherto undescribed specific and varietal 
concepts. 
Sundry resiniferous plants are used by the Indians of 
the northwest Amazon for domestic purposes. Impor- 
tant amongst these plants are Couwma macrocarpa Barb.- 
Rodr. of the Apocynaceae (the resin of which is exten- 
sively employed in caulking canoes), Protium heptaphyl- 
lum L.. of the Proteaceae (the brittle and aromatic resin 
of which is sometimes added to clay for making pots) 
and several species of Manilkara and Eeclinusa of the 
Sapotaceae. 
Notwithstanding the utilization of these and other 
plants, attention in this paper will be directed principally 
to three closely allied genera of the tribe Moronobeae of 
the Guttiferae: Moronobea, Platonia and Symphonia. 
Field studies have indicated that trees of these genera 
are, for most domestic uses, preferred by the natives of 
the northwest Amazon over all other species which yield 
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