I was offered some "krolyiang" the other day. The whole bag pictured costs just 500riels or USD0.125 cents. It's a kind of furry berry which is rather tasteless. The fur feels weird on your tongue. It is very small, and has a hard seed. It looks like the wolfberry/枸杞(gou qi) but I'm not sure. I tried to google to find the English name but had no luck.
I did find this interesting site listing tropical fruits by scientific name. Many of the links have photos so I had an interesting browse. Click on Morus Nigra or Black Mulberry - it looks like a stubby caterpillar!
Anyway, the tree must be common enough. There is even a market here in Siem Reap, Psar dum krolyiang, which is named after the fruit tree.
A friend of mine told me "My guess based on the name and her pictures is Dialium cochinchinense, a forest tree. The fruits are edible, the bark can be used to make a brown dye and the wood is good for things pillars and short joists (as in rice mills or carts). Anyone has any other ideas?