It’s not the nut of this tree that one eats, it’s the fleshy “acorn cup” behind the nut. You can see some ripe ones (orange) as well as some dark green unripe ones. You need to be careful harvesting these: although the eatable bit is tasty and nutritious, the nut is very seriously irritant. Get a bit of its oil on your skin, and you’ll have a painful sore that won’t heal for weeks or even possibly months.
My hand for scale.
©Clive K Semmens 2000