Fibroporia vaillantii 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. It has been/is sometimes considered to be a fungus causing dry rot, although that term is more often used for wood decay due to a different fungus, "Serpula lacrymans". The fungus grows on wood from coniferous trees, such as pine wood, under damp conditions,
Serpula himantioides appear as distinctive fruiting bodies on the exterior of the host. "S. himantioides" prefers the moist wood of coniferous hosts such as fir, larch, spruce, and pine. It is the causal agent of butt rot disease, the symptoms of which include rotting the heartwood at base of tree, as well as damage to the tap root and cores of lateral roots, but standing trees show no signs of infection. It also a common cause of timber rotting in buildings, which has made this pathogen difficult to differentiate from "S. lacrymans" because of their similarities. This disease often goes unnoticed initially