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 vigorous pumping movements of the abdomen and also by the activity of the ciliary tracts. The well-developed longitudinal muscles of the body wall of serpulids lack a special blood supply. The body surface in the larger serpulids, like "Serpula", has a rich blood supply, and the water in contact with this surface is constantly renewed. It seems probable that the outer body surface of serpulids serves as a respiratory membrane, supplying oxygen to the underlying muscles by diffusion. The biochemistry of the blood of "Serpula" is especially unusual in that the blood contains not only hemoglobin, but also chlorocruorin. While