Fomitopsis betulina (previously Piptoporus betulinus) commonly known as the birch polypore, birch bracket, or razor strop
A common parasite on birch trees, which continues to grow on dead wood.
White, smooth and rounded when young, later developing a convex, kidney or semi-circular shape. It is thickest at the point of attachment, which is stem like. The upper side ages to brown or grey and may become cracked.
It grows throughout the year.
It is inedible.
The white underside can be cut, to be used in bush-crafting as a temporary plaster on cuts and abrasions, the compounds within the fungi helping to staunch bleeding.
Magically, due to it use as a plaster, I would use this fungus for health and healing; as it grows on birch, also for rebirth, new beginnings and transformation.