Bracket fungi

Description:

Interesting fungi, and I still don't know what to think of them - at first I thought these were Turkey tail fungi, with those well defined and spectacular concentric bandes of colours above and tiny pores underneath (pic N° 5 and 6), and that shelf-like growth (pic N°4). But now, I'm not that convinced anymore... The surface feels velvety on touch, but their flesh felt corky, and slightly thicker and fleshier than what I would expect of Turkey tail. Those in pic N°4, on the lower side of that tree are bigger, between 7 and 10 cm across; while all those in other pics are much smaller, between 0,5 and 4 cm.

Habitat:

Found on a stump of the tree on a river bank. The river in question is one of the cleanest ones in Jura range, and here flowing through a mixed lowland forest.