Amadou

Tinder Fungus, also know as Ice Man Fungus, is a species of fungus which grows on the side of various species of tree and is widely used as a fire as a fire starter.
Amadou is produced from the flesh of this fungus, and is soaked in water before being cut into strips, and then beaten and stretched, separating the fibres. The resulting material is referred to as “red amadou”. The flesh was further used to produce clothing, including caps, gloves and breeches. Amadou was also used medicinally by dentists, who used it to dry teeth, and by surgeons, who used it as a styptic. It is still used today in fly-fishing for drying the flies. Other items of clothing and even picture frames and ornaments have been made from the fungus in Europe. The Amadou fungus was used as early as 3000 BCE, because when found, the 5,000-year-old Ötzi the Iceman was carrying four pieces of it, and chemical tests led to the conclusion that he carried it for use as tinder.
Mycologist Paul Stamets wears a cap made from amadou.
To read more: https://en.wikipedia.org/wiki/Fomes_fomentarius