Rough-stemmed Bolete

Well, the color of cap varies depending on growing habitat. Usualy they have darker brown or grayish cap while young, and yellowish brown while mature. But the ones in swamps has different color, and i don't know why exactly, because some of them are of dark grey color, even the stalks are a bit dim. The others, like this one, are snow white, and remain this color even mature. Also they seem to be more sturdy than usual brown scabers.