| Additionally, most wild animals only eat nontoxic plants, and most of these are edible for humans too. For instance, mushrooms are an excellent and often plentiful source of woodland food, but very perilous to eat unidentified. So if you don't know a death cap from a magic mushroom, you can often find a mushroom that is partly gnawed. If you don't mind sharing your food with a strange animal, this is safer to eat than your average shroom. Some of those many nasty looking shelf fungi you find on rotting logs are good food, and plentiful too. Fern are also very plentiful in most areas and generally not highly toxic, (in Taiwan some varieties are grown for food!) but some are highly carcinogenous, so don't eat unidentified fern unless you are really starving and prefer a slow death to a short one.
Other than that, only eat the sweet bumpy raspberries and blackberries you find--most smooth red or black berries you find in the wild tend to be poisonous or contain loads and loads of theobromine, theophylline, and/or caffeine (the first two are particularly potent)--so they are not a good food source either.
If you are in a marshy area, look for wild mint, catnip, and lemon balm--easily distinguished by the square stems and distinctive smells. They aren't a good food source either, but they freshen your breath after eating the shelf fungi and make a mean tea to boot. While in the marshy area, pull up all the cattails you see and keep the roots. You can peel them, dry them, and pound them to make a coarse flour (remove the fibers) and should you have a pinch of baking soda and a fire on hand, you could bake yourself some sivilized bread.
Wild carrot, or Queen Anne's lace, is a ubiquitous weed in meadows. They have a tough fibrous white root that may eaten, again a bad food source and with a very pungent flavor but you are desperate right? Don't confuse these for poison hemlock if it grows in your area! Look for the little black dot in the center of the flowers.
Then there's always the old staple of dandelion greens; best eaten young before it flowers, as it gets bitter with age. The jagged leaves are very distinctive, and it will make a nice salad with your shelf fungi, mint leaves, and berries. | 
