One day I noticed in the Bible, in Genesis 1:29, that God said that He had given every plant that produced seed and every tree that produced seed for us for food. My first thought was really? What about Poison Ivy, Dogwood, etc? In researching, I found that yes, most plants have some food or medicinal properties. One valuable website lists over 7,300 plants and their edible parts and medicinal uses. http://www.pfaf.org/index.php
There are only about twenty different plants that provide about 90% of the food that we eat, and yet there are over 20,000 species of edible plants in the world. There is much more food around us than what we realize.