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.
Diamante citron
The Diamante citron ("Citrus medica" var. "vulgaris" or cv. "diamante" − , or גינובה) is a variety of citron named after the town of Diamante, located in the province of Cosenza, Calabria, on the south-western coast of Italy, which is its most known cultivation point. This is why this variety is sometimes called the "Calabria Esrog". ""Esrog"" is the Ashkenazi transliteration of the Hebrew name for citron.
The Diamante citron was one of the most important varieties candied by the largest factories at Livorno, Italy; it was gathered from Liguria, Naples, Calabria & Sicily and then shipped into England and the United States.