The upas tree is a real tree, but not as poisonous as the legend would have us believe. The Kamus Besar Bahasa Indonesia entry for upas says:

upas n. 1. vegetable poison 2. a poisonous tree:Antiaris Toxicaria


Apparently its sap was (and for all I know may still be) used for poison darts.

See http://bpi.da.gov.ph/websitemedicinal/all/i/ipo.htm


Bingley


Bingley