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 just behind the head. There is a median, longitudinal, ciliated, thoracic fecal groove on the dorsal midline of the thorax. It is a broad, shallow, relatively indistinct trough running the length of the thorax and ending at the head. Worms of the genus "Serpula" have a distinct abdominal region, composed of up to 190 very short, wide segments. The terminal body region is the tiny pygidium, on which the anus is located. A fecal groove extends the length of the ventral midline of the abdomen. The fecal groove spirals across to the dorsal position as it reaches the thoracic region.