The Amylostereaceae produce crust @-@ like , dry and leathery @-@ corky fruit bodies on the bark of infested trees . The fruit bodies are 0 @.@ 5 – 1 @.@ 5 mm ( 0 @.@ 02 – 0 @.@ 06 in ) thick , irregularly shaped and are able to cover a large surface on the bark or otherwise can appear as small spots . They lie directly on the bark . The ochrous , grey or brownish fruit body ( hymenium ) have a smooth to warty surface texture and is turned outwards . It is bordered by a highly bent and wavy ( effuso @-@ reflex ) edge on all species except A. laevigatum , which have a churlish surface ( a tomentum ) and is usually dirty @-@ brown coloured . In some species , the tomentum stand clearly above and form a kind of roof above the fruit body ; if it completely surround this roof , there might appear cuplike shapes .