by field technicians of the Rubber Development Corpo- 
ration, a United States government agency, determined 
the identity of the various rubber sources and disclosed 
that the local methods of production then in use were so 
well developed that only slight changes and improve- 
ments were necessary to extract the maximum amount 
of rubber from the available trees. 
The various sources of rubber in Ceara and the methods 
of rubber production will be discussed in detail in this 
paper. 
The surveys showed that in Ceara only two genera 
were important, Hancornia and Manihot, occurring wild 
with the exception of some small plantings of Manihot 
in northern Ceara made during the last rubber boom. 
A few isolated trees of Castilla (eaucho) and two small 
colonies of Hevea were planted in damp mountains near 
Baturité, the Hevea seed coming from the territory of 
Acre. While extremely variable in yield, most of the 
few Hevea trees are of good quality and are now being 
tapped by the method used on most Eastern and African 
plantations (Plate XX XVIII, A) whichis by means of 
a panel carefully cut with a jebong knife (KMlippert 1942). 
For several months in 1944 smoked sheets of Hevea 
rubber comprised the larger part of Ceara rubber ex- 
ports. These were Far Eastern plantation sheets (Plate 
XXXVIII, B) produced under Japanese control and 
were being transported in German ships which were sunk 
near the coast by American planes and boats. Many fish- 
ermen earned more money during these months by sal- 
vaging the floating rubber than they had ever earned by 
fishing. 
HaANCORNIA 
This genus occurs from Paraguay and Bolivia through 
the states of Mato Groso, Sio Paulo, Goiaz and Minas 
Gerais to Ceara, Piauf, Maranhio and Para in Brazil 
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