This small tree grows along roadsides close to the bank of the Colo river west of Sydney.
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has fruits containing nuts.The internal structure of the fruit looks something like a mangosteen, but the thin pulp has an astringent flavour.
Inside the the thin shell is a pure white nut. It tastes pleasantly mealy, but not delicious. I spat it out in case it is poisonous.
I don't think it is a native Australian species and there are a lot of garden escapes in this area.
What species is it?