Tinder fungus is a species of fungal plant pathogen found in Europe, Asia, Africa and North America. It is inedible, and has been used primarily as tinder. The 5,000-year-old Ötzi the Iceman carried four pieces of Tinder Fungus, to be for use as tinder.
Tinder Fungus also refers to a number of species of fungi that catch and hold coals very well for an extended period of time, so as to not have to go through the effort of restarting a fire. Simply pry off a chunk of the smoldering Tinder Fungus and use it to light some tinder and remake your fire.