When trying to identify mushrooms, be sure to note the pore surface. Traits such as color, pore size, and pore pattern may help indicate the species. A key or guidebook will help you narrow it down, although remember that certain features may change as a mushroom ages. (Don't worry though, gills will never change into pores!) - See more at: http://www.mushroom-appreciation.com/identify-mushrooms.html#gills