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
Atromentic acid compound to p-hydroxyphenylacetic acid and oxalic acid. Atromentic acid Atromentic acid is a red-organge pigment found in fungi within the Boletales group. It is the precusor to variegatic acid and xerocomic acid, and is preceded by atromentin. As an example, it is isolated from "Serpula lacrymans". It is soluble in methanol. Variants include homoatromentic acid. This pigment has been studied and elucidated by Wolfgang Steglich and colleagues over decades . When atromentin is oxidised with hydrogen peroxide a yellow product is produced. A sodium hydroxide solution is also yellow, but when this is neutralized with acid the red atromentic acid