
1) Latex source
Found on
https://www.crosswordclues.com/clue/rubber-tree

(Ficus) House Plants - There are a wide variety of Ficus plants. There are evergreen or leaf losing trees, shrubs and climbing plants. Some are large trees found wild in tropical forests, and several are good for outdoor cultivation in southern Florida and southern California. A milky sap (latex), which soon coagulates, seeps from different kinds o...
Found on
http://www.encyclo.co.uk/local/10004

any tree that yields latex from which rubber is produced, esp. Hevea brasiliensis, of the spurge family, native to South America, the chief commercial source of rubber.
Found on
https://www.infoplease.com/dictionary/rubber-tree
No exact match found.