I had mentioned this in another thread, that I have a book call Foraging New England. It has many common plants indigenous to my area-nothing obscure, things you find every day. The book is broken down into regions such as oceanfronts, wasteland, woodland, etc. They only list a few of the available plants in any given area-they go by ease of recognition & local availability. They also list certain animals (freshwater clams, snails, etc). They outline harvesting season, preparation, nutritional value, and color plates to help identify them. The nice thing about the book is that it doesnt inundate you with 200 different plants in the area-only a few easily recognized ones. All in all, its a fantastic little field guide. They likely have them for other regions as well.