Fibroporia vaillantii 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, similar to the true dry rot fungus, "Serpula lacrymans". 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. Fibroporia vaillantii Fibroporia vaillantii, also known as mine fungus, white pore fungus, Antrodia vaillantii, Polyporus vaillantii, and various other names is a wood-decaying
Serpula lacrymans environments, the Himalayas, Northern California, the Czech Republic and east Asia. A recent study on the evolutionary origin and spread of this species using genetic markers (amplified fragment length polymorphisms, DNA sequences and microsatellites) on a worldwide sample of specimens suggested the existence of two main lineages, a nonaggressive lineage found in North America, and an aggressive lineage found on all continents, both in natural environments and buildings. "Serpula lacrymans" is considered to be the most damaging destroyer of indoor wood construction materials in temperate regions. In the United Kingdom alone, money spent by building owners rectifying damage caused by