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
For many centuries, citron's fragrant essential oil has been used in perfumery, the same oil that was used medicinally for its antibiotic properties. Its major constituent is limonene.