On the net on 8/28/2012 there was some discussion about edible plants. Harley suggested “Petersons Field Guide to Edible Wild Plants”. An Amazon search turned up this:

http://www.amazon.com/Field-Guide-Edible-Wild-Plants/dp/039592622X/ref=sr_1_1?s=books&ie=UTF8&qid=1346208295&sr=1-1&keywords=edible+wild+plants+peterson

I don’t have any experience with this book but I will get a copy.