tween the fingers to asticky mass of little elasticity. The 
tree is never tapped by the natives, not even for adult- 
erating the latex of Hevea Benthamiana, because, accord- 
ing to the rubber workers, the latex of the *‘seringueira 
tambaqui”’ (HZ. microphylla) often acts as an anti-coagu- 
lant when mixed with that of HZ. Benthamiana. 
In view of this, one result of Mr. MceMullan’s analysis 
is extremely interesting. The bark of Schu/tes & Lopez 
9593 gave the following analysis: ‘‘Resin (acetone ex- 
tract) 1.789%; Rubber hydrocarbon (benzene extract) 
0.97%. Good rubber in comparison with brasilensis.”’ 
The leaves, when studied, gave the following analysis: 
‘‘Resin (acetone extract) 6.83% ; Rubber hydrocarbon 
(benzene extract) 0.819%. Typical leaf rubber, soft, tacky 
and weak.’’ It would appear from this study that the 
composition of the latex from different parts of one indi- 
vidual of Hevea microphylla can vary rather appreciably. 
Hevea nitida Martius ex Mueller-Argoviensis in 
Martius FI. Bras. 11, pt. 2 (1874) 301. 
Brazit: Estado do Amazonas, Rio Negro, Serrinha, opposite mouth 
of Rio Issana. Caatinga. January 7, 1948, Richard Evans Schultes & 
Francisco Lopez 9586. 
In several caatingas in the upper Rio Negro basin, I 
saw evidence that, in the rubber boom of the past war, 
Hevea nitida was cut for a few days or weeks and was 
then abandoned. ‘Trees at the confluence of the Rio Negro 
with the Rio Uaupés and at Serrinha had from three to 
ten incisions. It is probable that natives, many of whom 
at the start of the rubber boom were unfamiliar with 
Hevea nitida, were attracted by the great density of this 
species in the caatinga formation and began to gather 
latex from it. Since the latex of Hevea nitida (formerly 
known as Hf. viridis Huber) has the reputation, not only 
of giving a worthless rubber, but also of ‘‘poisoning”’ the 
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