The citron-tree thrives in the open air in China, Persia, the West Indies, Madeira, Sicily, Corsica, and the warmer parts of Spain and Italy; and in conservatories it is often to be seen in more northerly regions. It was described by Theophrastus as growing in Media; it appears, however, not to be indigenous to Persia, but to have been introduced into that country and other lands from North India, where it was found growing wild by Dr Royle. It was early known to the ancients, and the fruit was held in great esteem by them; but they seem to have been acquainted with no other member of the Aurantiaceoe, the introduction of orangesand lemons into the countries of the Mediterranean being due to the Arabs, between the 1Oth and 15th centuries. Josephus tells us that “the law of the Jews required, that at the feast of tabernacles every one should have branches of palm-tree and citron-tree” (Antiq., xiii. 13, 5); and the Hebrew word tappuadι, rendered “apples” and “apple-tree” in Cant. ii. 3, 5, Prov. xxv. 11, &c., probably signifies the citron-tree and its fruit. Oribasius in the 4th century describes the fruit, accurately distinguishing the three parts of it. About the 3d century the tree was introduced into Italy; and, as Gallesio informs us, it was much grown at Salerno in the 11th century. In China, citrons are placed in apartments to make them fragrant. The rind of the citron yields two perfumes, oil of cedra and oil of citron, isomeric with oil of turpentine; and when preserved it is much esteemed as a sweetmeat.

Oribasii Sardiani Collectorum Medicinalium Libri XVII. , 1. i. c. 64 (De citrio) ; Gallesio, Traité du Citrus (1811); Darwin, Animals and Plants under Domestication, vol. i. pp. 334-6 (1868); Brandis, Forest Flora of North-West and Central India, p. 51 (1874).