Green Oak Lettuce boasts the highest amount of iron among all lettuces. It’s also higher in beta-carotene as well as vitamins C and A than its green counterpart. The leaves have a mild, sweet, and nutty flavour. Storage- Wrap it in a damp paper towel and put the head inside a plastic bag. Store in the refrigerator. If you’re storing individual lettuce leaves, spin them dry after washing and place them in a lettuce keeper in the fridge. A container is best to avoid bruising and bacteria buildup.