Serpula (fungus) cover the surface they are growing on (known as the substrate). The hymenophore, or spore-forming surface, generally has a wrinkled appearance. The species grow on, and digest, mainly coniferous wood, causing a process known as brown rot. One species, dry rot ("S. lacrymans"), is a highly destructive agent of houses. Damp structural timber is an ideal substrate for the germination of "Serpula" spores. The fungal hyphae penetrate the wood and release enzymes that break down structural polysaccharides such as cellulose. There may be no external indications that the fungus is present until the rot is far advanced and fruit bodies
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.