@carrotisland: You can absolutely eat the turnip. If you buy your turnip greens from a grocery store, the turnip is usually bought separately. Turnips need to be washed thoroughly, just as you would wash the greens. You can peel the turnip if the skin doesn’t look so hot. If the skin is okay, you can brush them under running water and keep the skin on.
Many people enjoy eating the turnips raw. If you are eating them raw, they are better young because the larger ones have a strong flavor.
You can cut your turnip into cubes and stir-fry them with other vegetables. You could steam them and then mash them with rutabagas. Many people add them to soup.