restate the pertinent historical facts and present as com- 
plete a synonymy as possible. 
In 1800, Humboldt collected material of Hevea along 
the Rio Tuamini near Javita and also along the Rio 
Orinoco at San Fernando de Atabapo, both localities in 
the upper Orinoco basin of southern Venezuela. ‘These 
collections were described by Kunth in 1825 under the 
name Siphonia brasiliensis. This has been taken almost 
unanimously as the first valid publication of the binomial. 
In the first decade of the nineteenth century, Count 
Hoffmannsegg received, presumably from the traveller- 
collector F. G. Sieber, who worked in Para from 1801 
to 1807, specimens of Hevea which he turned over to 
Willdenow for study. There is strong reason to believe 
that this material came from the lowermost course of the 
Rio Amazonas. Willdenow annotated the material with 
the name ‘‘Siphonia brasiliensis Willd.’’ and deposited it 
in his herbarium which was preserved at Berlin-Dahlem. 
These specimens represent the concept which we have 
come to know as Hevea brasiliensis. 
When Kunth published the name Siphonia brasiliensis, 
he described the two Venezuelan collections and cited 
them as the only basis for the description. He did not 
cite the Brazilian material of Sieber, but he did include 
in synonymy “‘Stphonia brasiliensis Willd. herb.”’ with 
the following footnote: ‘‘In specimine brasiliensi a 
Willdenoicum cel. Beauvois communicato (inque Museo 
Lessertiano asservato) foliola multo minora, subtus pal- 
lide viridia (nec albida).*” Also in synonymy, he included 
‘*Siphoniae species brasiliensis Adr. de Juss. Kuphorb. 
p. 40°° and ‘‘S. foliolis oblongis, acuminatis. Willd. 
mss.’’ Willdenow had the habit of making such abbre- 
viated descriptions on herbarium sheets or on envelopes 
containing specimens, and it is entirely probable that 
Kunth, who visited the Willdenow herbarium in Berlin, 
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