Turkey tail is the thin, leathery, fan-shaped bracket of Trametes versicolor, one of the commonest wood-rotting fungi in the world — instantly known by its concentric bands of brown, rust, grey and blue that fan out like a wild turkey's tail. Far too tough to chew, it is dried and simmered into a mild, woody-earthy tea or milled to powder, and it is the source of the well-studied polysaccharide extracts PSK and PSP.