Serpula (fungus) are formed. The strand mycelium of "Serpula", which can be up to 8 mm thick, are invasive and can spread over non-nutritive surfaces to find new food sources, even spreading through pores in stone, brickwork, and cement. After its initial growth period, the fungus can produce the water it needs and can continue growth into dry timber, eventually degrading it to powder—hence the term "dry rot". "S. lacrymans" is the most serious cause of building timber decay in the UK and northern Europe. The "Dictionary of the Fungi" (10th edition, 2008), suggests that the genus contains two species. , the
Serpula all sabellids and serpulids employ chlorocruorin as an oxygen transport macromolecule, "Serpula" is the only genus that appears to possess both hemoglobin as well as chlorocruorin. Chlorocruorin is an oxygen-binding hemeprotein whose affinity for oxygen is weaker than that of most hemoglobins. A dichromatic compound, chlorocruorin is noted for appearing green in dilute solutions, though it appears light red when found in concentrated solutions. Its structure is very similar to erythrocruorin, each molecule being composed of more than a hundred interlinked 16-17kDa myoglobin-like subunits arranged in a giant complex with a total weight exceeding 3600kDa. This enormous macromolecule is free