Dry rot be more distinctive in these species than water translocation. Water translocated in this fashion carries nutrients to the extremities of the organism; not, as is sometimes inferred, to simply render dry timber wet enough to attack. Coggins goes into more detail about water movement in "Serpula lacrymans". The perpetual saturation of wood with water also inhibits dry rot, as does perpetual dryness. "Dry rot" would appear to be a paradoxical term seemingly indicating decay of a substance by a fungus without the presence of water. However, its historical usage dates back to the distinction between decay of cured wood in
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