The lemon (Citrus limon) is a species of small evergreen trees in the flowering plant family Rutaceae, native to Asia, primarily Northeast India (Assam), Northern Myanmar or China. The origin of the lemon is unknown, though lemons are thought to have first grown in Assam (a region in northeast India), northern Myanmar or China. A genomic study of the lemon indicated it was a hybrid between bitter orange (sour orange) and citron. Lemon is a rich source of vitamin C, providing 64% of the Daily Value in a 100 g reference amount . Other essential nutrients are low in content. Lemons contain numerous phytochemicals, including polyphenols, terpenes, and tannins.[16] Lemon juice contains slightly more citric acid than lime juice , nearly twice the citric acid of grapefruit juice, and about five times the amount of citric acid found in orange juice.