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 (fungus) composing the family Serpulaceae. It is thought that the common ancestor was saprotrophic,and that ancestor to the latter two genera became mycorrhizal. Using molecular clock analysis, the split between "Austropaxillus" and "Serpula" has been estimated to have occurred about 34.9 mya, roughly coinciding with the separation of South America and Australia from Antarctica. The number of species is uncertain – the two species "S. lacrymans" and "S. himantioides" have been considered to be a single species, or the latter species has possibly five cryptic species within its complex. The members of the genus "Serpula" form flat brown fruit bodies that