Tinder fungus is a dark-grey to dark-brown 20 cm tall hoof-shaped fungus.
This fungus grows on dead and half-dead trees, with a preference for birch. Tinder fungus was once used as tinder for starting fires and was a standard part of a tinderbox. A tuft could be lit by striking two pieces of flint together. The smouldering tinder could then be used to light a wood fire. Rare beetles and wasps live in and lay their eggs in or on the tinder fungus. Because it is slow-growing and can become decades old, its removal would endanger the insects that live within it.