Euphorbiaceae
Hevea brasiliensis • Seringueira
The following quotes are from: Hobhouse, H (2003) Seeds of Wealth; Four Plants That Made Men Rich. Macmillian 255 p.

“Around 1770, the latex-producing tree was found at a low density of 3-4 every hectare, growing at random and being 'tapped' by local Indians who knew which trees yielded well and which were of greater or lesser value on that account. In Amazonia at that time, latex was used to waterproof cloaks and hoods, canvas tents and other objects to help people survive in the great rain forest. It was also used instead of candles, as there are no fat-bearing animals for tallow in the rain forest (equatorial animals do not suffer from cold and therefore carry little fat). One of the qualities of rubber is of course inherent in bows and arrows.”