Kumquat

Well ... what a bag of worms this one seems to have opened up.

The kumquat is a citrus fruit, which looks like a small orange, but it isn't an orange. Its scientific name is Citrus japonica. The orange (Citrus x sinensis) is actually a cross between the pomelo (Citrus maxima) and the mandarin (Citrus reticulata).

That's according to Wikipedia, anyway; see links above.

Wikipedia goes on to say that the kumquat was "previously classified as forming the now historical genus Fortunella, or placed within Citrus sensu lato". BBC Good Food, on the other hand, says "the kumquat ... is a member of another species, fortunella."

I'm a bit confused by all this; but what Wikipedia and the BBC do seem to agree on is that the kumquat is a citrus fruit but it isn't an orange.

However ... according to the Center for New Crops & Plant Products, at Purdue University (in West Lafayette, Indiana), it isn't even a citrus fruit: "They were included in the genus Citrus until about 1915 when Dr. Walter T. Swingle set them apart in the genus Fortunella, which embraces six Asiatic species." This is quoting a published (i.e. non–Internet) source from 1987.

If Wikipedia is to be believed, the bottom line would seem to be that the kumquat was classified as a citrus fruit until 1915, when it was placed in a genus of its own (Fortunella). Then, at some time since 1987, it was reclassified as a citrus, with the scientific name Citrus japonica. The other websites are (again, if Wikipedia is to be believed) out of date.

On a less controversial note, a different BBC Food page tells us that "Kumquats – sometimes called Chinese oranges – are the smallest and weirdest of the common citrus fruit. In contrast to other fruit from this group, the skin and zest are sweet, while the juicy insides are tart with a hint of bitterness. A winter treat, kumquats can be eaten whole, just as they are (you'll either love them or loathe them) or cooked with sugar, spices or spirits to make sweet compôtes and aromatic chutneys."