Clam chowder is any of several chowders containing clams and broth. Along with the clams, diced potato is common, as are onions, which are occasionally sauteed in the drippings from salt pork. Celery is frequently used. Other vegetables are uncommon, but small carrot strips might occasionally be added, primarily for color. A garnish of parsley serves the same purpose. Bay leaves are also sometimes used as a garnish and flavoring. It is believed that clams were added to chowder because of their relative ease to collect.