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 tidal fashion. In the central circulatory system, the blood moves anteriorly from the tip of the abdomen to the front of the thorax through a sinus enveloping the alimentary canal, and posteriorly through a ventral blood vessel. The ventral vessel and the sinus communicate with each other by segmentally arranged ring vessels, and by a dorsal vessel, a transverse vessel, and a pair of circumesophageal vessels situated at the anterior end of the thorax. The dorsal vessel in some of the larger serpulids, like "Serpula", possesses a valve and a muscular sphincter, probably to prevent backflow of blood from the