Ah ok, I understand. They both grow wild in Sweden, all over the place. I was aware of the difference but I didn't realise that there was actually a difference in species. The bilberry bushes have lighter leaves and blue/lavender berries and the and the "real" blueberries are almost black and the bushes are a bit smaller with darker leaves. I have noticed that, but I thought it had to do with how much light they got or something like that.
But I am no botanist.
I would guess you have both kinds in Russia too?