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.
Siracusa Lemon
The lemon plant originates in Burma, where it is found growing wild: from there it crossed the Middle East, Mesopotamia, and Palestine, to the Mediterranean, where it found favorable conditions to thrive. The natural habitat of the lemon lies in a strip from the 40° parallel in the North to the 40° parallel in the South: this strip includes California, Uruguay, Argentina, South Africa and the Mediterranean basin, in particular Italy, Spain, Greece and Turkey. In the Fifteenth and Sixteenth centuries, when there was an aristocratic monopoly on citrus growing, the use of lemons was confined to luxury foods.