Lettuce is mainly divided into three types: head lettuce, savoy lettuce and upright lettuce. Head lettuce: Similar in appearance to cabbage, its terminal leaves form a leaf ball, which is spherical or oblate. The edible part is a leaf ball and has a fresher taste. Savoy lettuce: Also known as loose leaf lettuce, the leaves are long oval, clustered like flowers, with long petioles and wavy and notched leaf edges. Upright lettuce: Also known as romaine lettuce, it does not form heads like savoy lettuce, but the heart leaves are rolled into a cylinder.