Citrus is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits. The genus "Citrus" is native to South Asia, East Asia, Southeast Asia, Melanesia, and Australia. For thousands of years, people in these areas grew citrus plants. Citrus reached Micronesia and Polynesia with the Austronesian expansion around 3000-1500 BCE. It reached the Middle East and Mediterranean around 1200 BCE, and then Europe.