Citron
There are also a number of citron hybrids; for example, ponderosa lemon, the lumia and rhobs el Arsa are known citron hybrids, some are claiming that even the Florentine citron is not pure citron, but a citron hybrid.
Citron
The citron is used by Jews (the word for it in Hebrew is "etrog") for a religious ritual during the Jewish harvest holiday of Sukkot, the Feast of Tabernacles; therefore, it is considered to be a Jewish symbol, one found on various Hebrew antiques and archaeological findings. Citrons used for ritual purposes cannot be grown by grafting branches.