It is said that origin of citrus was about 30 million years ago in Assam Province of Northeast India, and it became differentiated in many species and dispersed to Myanmar, Kingdom of Thailand and China and so on.
柑橘の原種は3000万年前のインド東北部のアッサム州近辺を発祥とし、様々な種に分化しながらミャンマー、タイ王国、中国等へ広まったとされる。