Making an observation here that is purely opinion (hope I don't offend as that is not my intention)...
While I believe plants are the foundation of survival; from the standpoint of food, that is a low priority in a survival situation and I am surprised how many are concerned with it. Maybe it's
too much Survivorman, but to expect to be able to forage, find (at the right time), properly identify, and potentially have to process a wild edible is a waste of time in a survival situation (in most cases).
Where plants become important in survival is fire, shelter, cordage, traps and tools. If food is an issue ~
knowing plants is important because they are what the REAL FOOD eats. It's survival, you don't need vitamins in the short term, you need calories.
That being said, I would worry more about makinig proficient traps/snares than wild edibles. Quoting John & Geri McPherson, "All nutrients required to keep the human body alive can be found in the animal kingdom."
Nonetheless, you can easily learn four wild edibles:
Pine Family
Oak Family
Grass
Cattails
By the way, I am not to shabby at edible/medicinal plants, but I doubt I will be looking to hard for them if food becomes an issue for me should a survival situation arise. My weakest links are in the details of traps and fire in wet weather when I really want them. When I practice them, I do good, when I really want them, I get impatient.
Peace, Chris
edible plants also tree identification. You'd be surprised how hard it is to find books that are actually useful in this area. But I'm reading everything I can find on the subject.
Echo ~ have three recommendations for you considering your geography...
http://home.alltel.net/medbow/
http://www.amazon.com/Native-Trees-...bs_sr_1?ie=UTF8&s=books&qid=1232219192&sr=8-1
http://www.amazon.com/Newcombs-Wild...=sr_1_1?ie=UTF8&s=books&qid=1232219220&sr=1-1
Hope it helps.