Here are the Link Might be useful - Too much too Explain. Look up yourself.
https://en.wikipedia.org/wiki/Mushroom
https://en.wikipedia.org/wiki/Edible_mushroom
http://www.bio.brandeis.edu/fieldbio/mgoldin/Alpha_Common.html
http://www.fungiphoto.com/CTLG/a_sys/A.alpha.html