I guess it was kind of pushing the bounds of fact, @Jeruba. However, aside from the cultivated foods you mention, a huge proportion of the weeds that grow in our lawns, gardens and wooded areas are, in fact, edible. Some of them are even tasty. I had the pleasure of following Euell Gibbons around a Maine island in my youth and learning that at first hand. Not that I’ve followed up on the lesson all that much, and I do admit that most of my food nowadays comes from Stop and Shop.
If our survivalist trainer jelly ever comes back, as he does from time to time, he could back up this claim. But yeah, “nearly everything that grows” is… out there. I guess we don’t eat many trees. In my defense I was thinking fauna more than flora at that point. And that’s true enough, considering that we eat snakes, scorpions, grubs, all kinds of crustaceans and molluscs… and even things that don’t appear to be that appetizing, such as eggs, for example.