He ‘castill6a” is a tree of large ‘proportions, reaching to 
a «height of from 12 to 18 metres; its trunk with a diametre of 
from 060 to 0™90, is of an ashy gray color, smooth and spar- 
ingly branched. The leaves are large, greater, indeed, on the 
new plants than on the full grown trees and its fruit is of an 
oily’ nature. 
“These trees grow in considerable quantities at the sources 
or head-waters of the affluents of the Amazon on the latter’s 
right bank, such ds the Jurua, the Purts, the Madeira, the 
Tapajoz and the Xingu, and on its left bank in the valleys of 
the Japura, the Ica, the Rio Negro and the Trombetas Rivers. 
Abundant “cauchaes” or forests of cautchou trees exist also in 
the region of the River Tocantins and of the Araguaya. 
The ‘‘castilloa” is found therefore in the same regions as 
those in which the “seringueiras” flourish; it exacts a warm 
climate, a clayey or clayey-silicious soil, but does not thrive in 
swampy ground or such ‘as is easily inundated during the 
rainy season. 
The latex is found as much in the bark as in the alburno 
and each tree felled produces on afi average about 50 litres of 
latex or say from 18 to 20 kilos of rubber. 
_ “Ceara” is the mundial denomination of another quality of 
Brazilian rubber, the rubber of the Manicoba tree. The mani- 
coba manihot glaziovii i is a handsome tree 10 to 15 metres high, 
and a native of the Northeastern region of Brazil. -1t$ trunk 
presents a diarhetre of from 20 to 50 centimetres and it possesses 
few branches; its wood-fibres are weak and light. The cortex, 
which possesses lactiferous vessels in abundance, is protected 
by ‘a silicose layer, easily removable. It is a plant of rapid 
‘gtowth. 
~~" According to a essing made by Dr. Ule, there are 
“four species of manioh, the m. glaziovii, the m. piauhyensis, the 
m. dichotoma and the m, heptaphylla, the which exist almost 
throughout all Central Brazil, being specially abundant in 
Ceara, Piauhy and Bahia. 
. Little exigent, it thrives in regions where the temperature 
oscillates between 22° and 36°, on low-lying ground and it 
develops itself well in lands of great altitude, in which the 
thermometric average temperature is about 1B’, resisting even 
the hoar-frost. , 
‘It is indifferent to this tree whether the climate be damp or 
dry, as long as the soil is dry. 
The species most appreciated are those from Piauhy and » 
the Jequié (“sertdo or back-woods of Bahia). Those of Piauhy 
present two varieties: the white and the black species, the white 
being the most renowned. They are of small size, with abundant 
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