In 1870, Luther and Eliza Tibbets left Maine for Riverside, California. They asked the U.S. Department of Agriculture to suggest fruit trees that would grow in their new home. They were sent three "navel" orange trees, which thrived, producing sweet, seedless oranges. "Mother Naval," an original parent tree, still stands in a Riverside park and has been designated a state landmark. Today, more than 6,000 citrus growers make up the Sunkist Cooperative.