Actually, no one can really tell for certain which ancestral plants are responsible any given cultivar we know today except for very recent ones.
There are several American citrus plants like for instance clementine that started showing up in Texas and the panhandle in the last century whose origin is still debated.
That said the mandarin orange is likely the only really wild citrus fruit we eat today that hasn’t been totally altered beyond recognition. Although I do see Pomelo-flavored stuff here and there.
Citron and papeda are the other two ancestral species.
All oranges, grapefruits, and tangerines are essentially a cross between a mandarin orange (wild) and a pomelo, except many of them were perfected via cross-breeding back along there own lines.
Lemons and limes are the other side of the family. You can tell there ancestry lies with the citron and papeda.
That said I’m not even really sure anyone knows when or exactly where the the first lemons/limes were bred, as this event significantly predates the genesis of oranges and has virtually no known documentation or verbal history associated with it. Most likely it happened in Southeast Asia.
It bears mentioning that kumquats are not considered to be in the same family as other citrus. In fact many botanists deny that they are actually a citrus and say they are just a tiny family of plants that are very closely related. They were not made edible through hybridization – just selective breeding. Nevertheless they have now been crossed with mandarins. Wild types can still be found with edible berries. They’re not very tasty though as there mostly seed and pulp.
All citrus plants, like so many other plants used by man, are from a fairly primitive lineage of flowering plants like roses and magnolias.
These answers are superb!
In general, most of the fruits listed above like oranges, lemons, limes, grapefruits, tangerines and mandarins come from an area where Northeastern India, Myanmar and Yunnan, China all come together. To some extent Southeast Asia in general is also listed. In one case, Assam, India is listed as an origin. For a few of the fruits, other places like the Indian Ghats, Japan and Vietnam are also listed. But as you can see, they all come from that part of the world. This was discovered via genetic testing. So these fruits were created via hybrid breeding in that part of the world a long time ago. I know that human-created oranges are known from Southern China for thousands of years.
The commenter is correct. All citrus derives from mandarins, pomelos, citrons and papadas.
The other commenter is correct that one of the two main lime varieties is the Key Lime. But that is not where it comes from. The Florida Keys are simply one of the late places where it was cultivated, where it gained fame in particular for Key Lime Pie, which I like myself. The Key Lime ended up there after creation in the aforementioned part of East Asia. From there it went via the Middle East -> Sicily -> Sardinia -> Spain -> the West Indies -> Florida Keys.
Mandarin oranges are the only one of the above that is actually a native plant, correct.
- However, we still do not know which one – grapefruit, orange, lemon, lime, tangerine – is a very recent breed. I will tell you that it goes back only to the 1700’s. And we would also like to know where it first showed up.
- Although a commenter mentioned one of the two main lime varieties – Key Lime – we still do not know what the other main lime variety is. Any guesses? I think this is actually the most popular lime variety in the stores and is seen much more often than the Key Lime.