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.
Watermelon
The citron melon or "makataan" - a variety with sweet yellow flesh that is cultivated around the world for fodder, and the production of citron peel and pectin.