Cassia (Cinnamomum aromaticum, synonym C. cassia) is an evergreen tree native to southern China, Banglaesh, India, and Vietnam. Like its close relative, cinnamon (Cinnamomum zeylanicum, also known as "true cinnamon" or "Ceylon cinnamon"), it is used primarily for its aromatic bark, which is used as a spice, often under the culinary name of "cinnamon". The buds are also used as a spice, especially in India, and were once used by the ancient Romans.