Comment by nkurz

Coincidentally, a friend recently showed me his "mushroom hat", which is made from "amadou": https://en.wikipedia.org/wiki/Amadou. It's a wonderful lightweight texture, somewhere between leather and felt. A description of the manufacturing process (and the mushroom which it comes from) is here: http://frimminjimbits.blogspot.com/2012/08/mushroom-cap.html