Can humans eat grass?

According to Wildwood Survival magazine, "of the many grasses found in North America, all but a few are edible." The magazine also states that the most edible part of grass is the seeds.

The United States Department of Agriculture lists hundreds of types of grasses, many of which have culinary applications, such as wheatgrass, oatgrass and barley. According to the Encyclopedia of Life, there are over 10,000 species of grass covering 20 percent of the Earth's surface, including food crops, such as sugar cane and grains. Grass is characterized by having a hollow stem that grows from the base of the plant.