Turkey tail is a fungus that grows on dead or dying trees, often oak trees.
It was given this name because it looks like the tail of a turkey in the way it fans out, and because its colors are often similar to the bird's feather colors.
Unlike mushrooms (another fungus), turkey tail has no stalk. Most of it is growing inside the bark of the tree. The part you see on the outside is sort of like its flower, except it doesn't make seeds, it makes tiny spores like a mushroom does.
Turkey tail grows in rings, often one ring every year. It can be brown, grey, or white, and sometimes even orange.
The turkey tail fungus helps break down the dead tree. Then the nutrients from the tree can return to the soil and be used again by a younger tree.
Turkey tail is not edible by people. They are too hard and tough. But other animals like squirrels, turtles, and some bugs eat them.