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
Nemapogon granella are uniformly greyish-brown and surrounded by a fringe of long hairs. On the head, the adults have a tuft of yellowish-white hairs. The caterpillar larvae eat rotting wood in the wild, though they prefer bracket fungi, usually Polyporales. Their mainstay food included Polyporaceae such as sulphur polypore ("Laetiporus sulphureus"), dryad's saddle ("Polyporus squamosus") or turkey tail ("Trametes versicolor"), as well as Fomitopsidaceae, e.g. birch polypore ("Piptoporus betulinus"). But they have also been found on "Serpula lacrymans" of the quite unrelated Boletales. Larvae in association with humans will feed on a variety of dry organic material, such as dried fruit (e.g.bilberries,