English: Common Mazegill fungus (Cerioporus mollis) This fruiting body (apparently two, fused together) was found growing on a fallen log, on what would originally have been the underside (in this item, I will write as if the fungus is still growing on the underside, but the log shown here had in fact been turned over at some point, exposing the Common Mazegill to view). The fallen log was located at the edge of some woods, only a few metres from a footpath.
The pores in this species are fairly large, spaced almost 1 mm apart. The fungus shown here measured about 8 cm from left to right (a much larger patch was present on the same log; shown on the same scale, it would more than fill the image). As is usual with poroid fungi, the pores develop strictly vertically, regardless of the slope of the surface on which the fungus is growing.
In general, fungi cannot simply be identified by comparison with photographs; in some cases, an examination of microscopic features is required. However, this species has some distinctive features that allow identification to be made without use of a microscope (I made an examination of a very small fruiting body located near the ones shown in the photo); for example, a cross-section revealed one very helpful aid to identification: there is a distinctive thin black line (visible through a hand-lens) between the creamy flesh and the dark brown upper surface.
This is a common species, found all year round on dead wood (almost always of deciduous trees); it causes white soft-rots. [For identification, and details of habitat, I largely relied on "Fungi of Switzerland (Volume 2: Non-gilled fungi)", by Breitenbach & Kräntzlin].