Romaine Lettuce is the most upright growing of all lettuce types. Its heavily ridged leaves grow erectly and tightly to form an elongated head. Its outer leaves, rich in chlorophyl have lime colors while its inner leaves are yellow to creamy. Its blanched heart becomes translucent white at its core. Romaine Lettuce has more texture than flavor. Its leaves are substantial, crunchy and succulent with a mild flavor.