Crisphead lettuce seeds produce heads with stiffer leaves than others. This includes iceberg lettuce, but also any lettuces that form a tightly wrapped head. Crisphead lettuce grow upright, and are held off the ground without a lot of drooping wrapper leaves. At one point in time, crisphead lettuce dominated the produce sections of most groceries. The variety known as Iceberg lettuce got its name because it could be shipped from Salinas, California all over North America and it stayed fresh if it was covered in ice. Since the 1970s iceberg lettuce has fallen out of fashion and has been replaced by romaine lettuce, arugula, mesclun mixes, and many other leafy greens. But crisphead lettuce keeps better so it still accounts for over 60% of the lettuce produced in California.
