ACROSS UNKNOWN SOUTH AMERICA 
heavy that none floated. Hence the ever-clean surface 
of all the streams. 
We were then in a region of truly beautiful forest, 
with figueira (Ficus of various kinds), trees of immense 
size, and numerous large cambard. The bark of the latter, 
reddish in colour, when stewed in boiling water, gave a 
refreshing decoction not unlike tea and quite good to 
drink. 
Most interesting of all the trees was, however, the 
seringueira ( Siphonia elastica), which was extraordi¬ 
narily plentiful in belts or zones along the courses of 
rivers in that region. As is well known, the seringueira, 
which grows wild in the forest there, is one of the most 
valuable lactiferous plants in the world. Its latex, 
properly coagulated, forms the best quality of rubber 
known. 
There are, of course, many latex-giving plants of the 
Euphorbice , Artocarpce and Lobelice families, but no 
others are perhaps such abundant givers of latex as the 
Brazilian seringueira (of the Euphorbice family), a tree 
plentiful not only in Matto Grosso on all the head-waters 
and courses of the rivers flowing into the Amazon, but 
also abundant in the provinces of Para and the Amazon. 
In less quantities the seringueira is also to be found in 
Ceara, Rio Grande do Norte, and Maranhao. 
The seringueira prevailed chiefly near the water, in 
swampy places, or in places inundated when the river was 
high. Never was the tree to be found at a distance away 
from water. 
Its height varies from twenty-five to fifty feet. Its 
diameter is seldom more than thirty-five inches. Its 
leaf is composed of three elongated leaflets, smooth-edged 
and complete in themselves. The seed is smooth-skinned, 
and of a reddish tone. The fruit consists of a well- 
rounded, wooden capsule enclosing three cells which con¬ 
tain white, oily almonds not disagreeable to eat. From 
4 
