from The Century Dictionary.
- noun A name of two Australian trees and their fruits: Rancooria acidula (Owenia acidula of F. von Mueller), belonging to the mahogany family, with fruits the size of a small peach, which are eaten by the colonists and aboriginals.
- noun Same as
Sorry, no etymologies found.
The Australian Encyclopaedia (the older and fuller 1956 edition) is probably the source of the entry for quinine-tree in the first edition of my dictionary; it also identifies Petalostigma quadriloculare as quinine-tree but adds the names crab-tree, native quince, and emu-apple, mentioning that all these names are shared by other plants.
The Macquarie agrees with it about emu-apple but doesn't have crab-tree either.
The Australian Pocket Oxford Dictionary already has an entry for emu-apple but calls it Owenia acidula (also called native nectarine or native peach).