Citrus fruits have stippled rinds that surround pulp that's tart, juicy, and rich in vitamin C and other nutrients. Most citrus fruits are first peeled, then the pulp is either eaten out of hand or squeezed to make juice, but some, like the kumquat, are eaten peel and all. The peels contain fragrant oils, and their zest is often used to flavor foods. When buying citrus fruit, select specimens that are smaller, thin-skinned, and heavy for their size. They keep longer if you store them in the refrigerator.