Schizophyllum commune.
Basidiomycota > Class Agaricomycetes > Family Schizophyllaceae.
A very common mushroom, up to about 4 cm wide with a lateral or no stem.
It is fan shaped on the sides of a log, more irregular on horizonal surfaces.
The edge is often lobed.
Adjacent ones may fuse to form irregular shapes.
Occasionally found on living wood but usually on dead where it causes white rot.
The upper surface is densely covered with small, white, grey or brown hairs.
The pore surface is pale cream, white or pink but grey as it ages.
It appears to have gills but these are thick folds in the hymenium.
The folds can split or double when it dries out then reform when it rehydrates.
J.F.