Dry rot species of fungi cause brown rot decay, preferentially removing cellulose and hemicellulose from the timber leaving a brittle matrix of modified lignin. The term "dry rot" is somewhat misleading, as both species of fungi "Serpula lacrymans" and "Meruliporia incrassata" require an elevated moisture content to initiate an attack on timber (28–30%). Once established, the fungi can remain active in timber with a moisture content of more than 20%. At relative humidities below 86 percent, growth of "Serpula lacrymans" is inhibited, but it can stay dormant at relative humidities down to 76 percent. These relative humidities correspond to equilibrium moisture contents
Pulvinic acid acid, isoxerocomic acid, variegatic acid, variegatorubin, xerocomorubin, chinomethide, methyl bovinate, pulvinone, badion A, norbadion A, bisnorbadiochinone A, pisochinone, and sclerocitrin. Pulvinic acid Pulvinic acid is a natural chemical pigment found in some lichens. Dimers of pulvinic acid have been found in the fungi "Scleroderma citrinum" and "Chalciporus piperatus". Hydroxypulvinic acid pigments (pulvinic acid type family of pigments) have been found in "Boletus" (e.g. "Boletus erythropus"), "Boletinus", "Chalciporus", "Gyrodon", "Leccinum", "Pulveroboletus", "Suillus" (e.g. "Suillus luteus", "Suillus bovinus", and "Suillus grevillei"), "Paxillus" (e.g. "Paxillus involutus"), "Serpula" (e.g. "Serpula lacrymans"), "Xerocomus" (e.g. "Xerocomus chrysenteron"), "Hygrophoropsis" (e.g. "Hygrophoropsis aurantiaca"), "Retiboletus" (e.g. "Retiboletus nigerrimus"), "Pulveroboletus"