Birch Polypore

This is the fruiting body of the birch polypore Fomitopsis betulina. It's quite big at around 6" across.

How good it is to be able to make an identification with some certainty, though just to confuse me on some sites it is called by its old name, Piptoporus betulinus.

It's possibly the most common fungus in the local woods at the moment though its season is supposed to be from August to November.

In places it has colonised whole branches but if one looks closely one notices that the ones at the top of the branch.... 

....were probably active a season or two ago and that the fungus has steadily....

.... worked its way down the branch.

It's a useful fungus. One site describes it thus: "It has been used as a tonic for the immune system, as an antiseptic to clean wounds and promote healing, a plaster that is microporous, antifungal and antiseptic, and was probably used by Bronze Age man to get rid of parasitic worms." It adds, "The mushroom has very beneficial effects on the immune system and many people drink a tea made from the fresh or dried fungi and swear by its positive effects." There - a local replacement for rooibos tea? There's more - the site is here.