Rhobs el Arsa
The Rhobs al Arsa has long been viewed as a citron hybrid, though a different cultivars have been suggested for the parent, for example, Moroccan citron as a male parent and sour orange as the female parent, citron or lemon and a mandarin., or citron and the lime. Detailed genomic analysis has shown Rhobs al Arsa to be highly similar to several cultivars of "Citrus limetta", the limetta or Persian sweet lime, and likely shared a common origin with them, arising from a cross between citron ("Citrus medica") and sour orange ("Citrus" × "aurantium"). The common lemon arose from a distinct hybridization event involving the same two species.
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.