Birch Polypore - Piptoporus betulinus
See also: Razor Strop Fungus
This is one of the most easily identified and common fungus found throughout northern temperate climes such as Europe and North America. It is an excellent fungus to teach children to recognise as it is neither poisonous nor rare, very distinctive, and can be found anywhere where there are dead birch trees.
Piptoporus betulinus can be found growing on dead birch trees be they in woodland, in your garden, in somebody else's garden or in a habitat or firewood pile. The fruiting bodies, or rather the bit of the fungus you can see, only appears on dead birch, but the mycelium, the unseen, living part of the fungus, can colonise old or unhealthy trees for several years before the fruiting body appears.
Birch polypore is in the family Fomitopsidaceae and is known as a bracket fungus, a fungus which grows horizontally out of the side of trees like a miniature shelf. Birch polypore are semi-circular and very smooth and rounded in appearance. There is no stem, the fungus growing straight out of the tree, the top being beige to dark brown in colour and the underside a beautiful pure white with slightly scalloped edge. The spores are produced on the underside and are white in colour.
If broken open when young the flesh will be firm and white with a pleasant earthy smell, but as the fungus ages it becomes tough and discoloured. The fruiting body is produced annually, and you can often find several growing together on one trunk. After the first year the fungus doesn't produce spores, but the fruiting body remains on the tree, providing a micro-habitat for all sorts of flies and beetles to lay their eggs in. Try breaking them open in the spring and you are bound to find something creeping about inside.
Can I eat it?
Not really recommended. The fungus is not poisonous, but goes hard and leathery pretty quickly which doesn't help its edibility. If caught young then it probably wouldn't hurt you, but there are lots more tasty and exciting fungus to hunt for and eat.
Additional Piptoporus Trivia
Birch polypore developed its other name, Razor Strop Fungus, as strips of the upper surface flesh used to be torn off and used as a strop for sharpening razors on by poor Victorian families. Another clue as to why its not really very good for eating!
Before the invention of polystyrene, Piptoporus was used to stuff packing cases by entymologists to keep their specimens safe. The polypore are extremely light and also readily available.
Famously Otzi the Iceman, a body found in a crevasse in the Alps of a prehistoric mountaineer in 1991, was carrying Piptoporus betulinus. He was carrying two pieces of dried Piptoporus on a thong around his neck, and it is thought that it was then used medicinally to stave off various flukes and internal worms as it contains antibiotic oils which attack mycobacteria. It could also have been used as tinder for starting fires.
Mushrooms and other fungi of Great Britain and Europe - Roger Philips
The Encyclopedia of Fungi of Britain and Europe - Michael Jordan
See: http://www.uksafari.com/birchbracket.htm for a picture