This collection of Allen was the first made in Colombian 
territory. The astuteness of Allen and his native informants in 
recognizing this as a different species is extraordinary. Later 
collections have shown that is is not a rare species in the north- 
west Amazon of Brazil and Colombia. 
Micrandra Rossiana has been known from Brazil, Colombia 
and Venezuela. Intensive studies of Micrandra have indicated 
that the distribution of M. Rossiana is much wider and more 
abundant in the Colombian Vaupés—especially in the Rio Apa- 
poris and its affluents—than in any other area of the northwest 
Amazon. 
Micrandra siphonioides Bentham in Hooker, Bot. Journ. 6 
(1854) 371. 
COLOMBIA: Comisaria del Vaupeés, Rio Papuri, Macu-Parana. Alt. c. 200 m. 
“Trees averaging 25 m. in manchas but with numerous isolated specimens 
measuring 35 m. when felled. Average diameter about 75 cm above the 
often prominently developed buttresses, which in large specimens often 
extend upward for 3-4 m. from the ground. Flowers greenish yellow, on 
axillary new growth. Bark reddish brown, of varying thickness, that on the 
trunk often 2-3 cm. while on the buttresses it seldom exceeds | cm. Latex 
pale yellow, seldom flowing freely, usually coagulating in the cuts in the 
manner reminiscent of some species of Castilloa [sic], being removed after 
an interval of about three days as scrap, which is wound into balls. Tensile 
strength excellent, being considerably better than Acre Fine Hevea. Known 
locally as arara siringa or buhawakpuh (Tucano).” August 11, 1943. P. H. 
Allen 3050.—Same locality. “Tall trees, averaging 25 m. tall in manchas on 
margins of low sandy caatinga, but with numerous isolated specimens on 
clay ridges reaching 35 m. Average diameter about 75 cm. above the often 
prominently developed buttresses, which in old specimens often extend 
upward for 3-4 m. from the ground. Flowers greenish yellow, on axillary 
new growth. Bark reddish brown, of varying thickness, that on the trunk 
often 2-3 cm., while on the plank buttresses it seldom exceeds | cm. Latex 
pale yellow, seldom flowing freely, usually coagulating in the cuts in a 
manner reminiscent of Castilla. This scrap can be removed after an interval 
of about three days, usually being wound into balls. Tensile strength 
excellent, considerably better than weak fine Hevea. Some resin content. 
Known locally as arara-siringa (Geral) and bu-ha-wak-puh (Tucano). See 
pickled fruits, which resemble those of Hevea.” August 15, 1943. Allen 
3061. 
Micrandra siphonioides is a very abundant species in the 
northwest Amazon. Seldom, however, have such detailed field 
notes been appended to voucher specimens. For this reason, it 
105 
