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.
Palestinian sweet lime
Citrus limettioides, Palestinian sweet lime or Indian sweet lime or common sweet lime, alternatively considered a cultivar of Citrus × limon, "C." × "limon" 'Indian Lime', is a low acid lime that has been used in Israel for food, juice and rootstock. It is a member of the sweet limes. Like the Meyer lemon, it is the result of a cross between the citron ("Citrus medica") and a mandarin/pomelo hybrid distinct from sweet and sour oranges.