Bracket fungus, also known as shelf fungus, is easily recognized by the semicircle-shaped shelves growing around the base of a tree. A key identifying characteristic of bracket fungus is the growth that emerges right out of the tree bark. Bracket fungus does not have stems similar to mushrooms. 
http://waynesword.palomar.edu/bracfung.htmhttp://www.encyclopedia.com/doc/1O142-bracketfungus.html
