Phlebia rufa possibly

 

Phlebia rufa possibly on a really wet well decayed fallen birch branch. The colour is supposed to be very variable indeed, with brown, yellow or pinkish tones being seen in different images. However it may be worth noting that Phlebia acerina, if recognised in Europe, is similar but tends to be lighter coloured and yellower. The two taxa used to be regarded as conspecific (and still are in Europe) but are now claimed to be two separate species, confirmed by DNA studies in America.  

There are other ways to tell the two apart. A test worth carrying out is KOH, as Phlebia rufa should darken upon application, whereas Phlebia acerina should not. Generally, basidiomata of Phlebia rufa are thinner and less robust than those of Phlebia acerina. The margins of Phlebia acerina are usually entire and often detach from the substrate, whereas those of Phlebia rufa are fibrillose and closely appressed - I didn't see finrillose margins. In addition. the hymenial surface is interrupted by white, felty to woolly mycelia in many specimens of Phlebia acerina.

It is rather a moot point, because even in the American text, Phlebia acerina is not recorded in Western Europe.

One way to separate Phlebia rufa and Phlebia radiata is in the arrangement of the "polyps" which are never circular in Phlebia rufa and do tend to be radially arranged in Phlebia radiata. Ph;ebia radiata is also geerally more brightly coloured, sometimes quite a bright orange.