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 the mouth. While they are primarily feeding structures, the radioles also serve as respiratory organs. The radioles of different "Serpula" species are typically red, pink, or orange in color, with white transverse bands. Astaxanthin, a carotenoid pigment, is responsible for the bright red color of the crown of "S. vermicularis". There are usually about 40 radioles in an adult. One of these radioles, called an "operculum", is a highly specialized structure located on the dorsal part of the head. The operculum consists of a long, thick stalk with a cartilaginous, cone-shaped plug at the distal end. This plug can be