Some are delicately growing out of the sides of living or dead trees.
Some come in pretty strange textures and colors. Scuttlebut is that the red ones are poisonous but I don't eat any of them just to be on the safe side. I like my mushrooms to come from a bin in the supermarket.
I like the ones that have the delicate flutes on the underside, although I have also been warned that that is another sign of their being poisonous. I think if they are growing in the ground, they are either poisonous or endangered and in either case, I probably should leave them alone.
If red ones are posionous, what about the rust colored?