Fibroporia vaillantii
Fibroporia vaillantii, also known as mine fungus, white pore fungus, Antrodia vaillantii, Polyporus vaillantii, and various other names is a wood-decaying fungus which can occur on timber in humid conditions. The fungus causes brown rot of pine wood, in which cellulose and hemicellulose are broken down, leading to brown discoloration and shrinkage of wood. Description
The fungus grows on wood from coniferous trees, such as pine wood, under damp conditions, with a wood moisture content of 40 to 50 percent. In humid atmospheres, the white cotton-like mycelium can grow on wood surfaces and cross inert materials. In newly grown mycelium, fine drops of clear liquid may be present. The optimal temperature for growth is ; it will grow at temperatures between . The fruit body is an irregular white plate with a thickness of 2 to 12 mm. References

Fungi described in 1815
Fungi of Europe
Fomitopsidaceae