Which mushroom did Ötzi the Iceman carry and is also known as the birch polypore?

The mushroom Ötzi the Iceman carried that is also known as the birch polypore is Fomitopsis betulina.

Ötzi, a Copper Age man whose naturally mummified body was found in the Alps in 1991, carried fragments of this tough bracket fungus. He lived roughly 5,300 years ago. The fungus grows mainly on birch trees, usually as a saprobe that causes brown rot in dead or weakened wood.

Fomitopsis betulina was formerly called Piptoporus betulinus, a name still common in older books and databases. It is also known as birch bracket or razor-strop fungus because its leathery fruiting body was historically used for sharpening razors.

A common mix-up is Fomes fomentarius, the hoof or tinder fungus, which Ötzi also carried. That species is not the birch polypore. The purpose of Ötzi’s birch polypore remains uncertain, although proposed uses include medicine or carrying material for practical purposes.