Perhaps the most nutritious and powerful vegetable of all is one that's easily overlooked: lettuce! Let's go beyond iceberg and explore the many different types of lettuce and how each can make a delicious and positive contribution to your next healthy meal. There are so many varieties of lettuce and greens popping up at the markets and stores, each more beautiful than the next. If you're in a little bit of a salad rut, reading about some of these lesser-known lettuces may tempt you to try something new. GREEN LEAF LETTUCE: Salad greens are any leafy green vegetable traditionally used