Romaine lettuce is medium to large in size with an elongated shape and stiff, upright leaves. The thick heads are loosely connected to a central blanched base and the leaves, averaging 10-15 centimeters in length, are broad with many folds and creases. The outer leaves are dark green with a prominent white central rib, and as the leaves grow smaller in the center, they become paler in color almost fading to white. Romaine lettuce is crisp, succulent, and crunchy with a mild, slightly bitter taste.