Does rubber come exclusively from rubber trees?
Natural rubber, latex, is derived from the sap of the rubber tree. A great deal of what is called rubber these days is one of several different synthetic rubbers.
Rubber Trees grow mostly in Brazil. But they can also grow in other places. the first place that the rubber tree was grown outside of Brazil was in the botanical gardens in England. Indonesia and Thailand, but they originated in Brazil, hence the name Para rubber. Joseph Priestley noticed that it would erase - rub out - pencil marks - hence the name rubber. The rubber trees are most likely found in Thailand.
Rubber came from India. It is made from the tree sap in some trees. People first "tap" the tree, meaning cutting it in a horizontal and vertical direction. The name "Rubber" came from when a Staitioner accidentally figured out that it could erase pencil marks, so it came from India, and rubbed, it got named "Indian Rubber"