Common Poisonous Plants by Dr. Nancy Turner is the top of the line field guide to deadly botanical beauties you could come across while exploring the great outdoors.
This book is top quality in information, details, poisoning symptoms, and content! It is well worth the expense, which is a good amount. The book itself contains, plants, mushrooms, and fungi that could be hazardous to humans and animals alike. The main highlight, by far, is the toxicity section on each of the poisonous plants. The symptoms of ingestion, (contamination) are well described and could easily compell the reader to shudder. The symptoms are specific to every single plant, so that an infected person's life could easily and efficiently be saved. There is also a very helpful insight on treatment of potential poisoning.
The book is so specific, it even tells you the degree of toxicity! Unfortunately, this book is very expensive and going out of print. So, any hardcore naturalist or interested botanist should purchase this online ASAP!