Lettuce is a type of leafy green vegetable that belongs to the genus Lactuca in the family Asteraceae. It is commonly used as a salad ingredient and has a mild, slightly bitter taste. The plant grows upright and produces long leaves that form a head or rosette. There are several varieties of lettuce, including iceberg, romaine, butterhead, and leaf. Lettuce is high in nutrients such as vitamin A, vitamin C, folate, calcium, and iron, making it an excellent addition to a healthy diet.