Because this is apparently super important! I’d been having difficulty in the produce aisle finding what I want, so I put together this handy dandy guide.
There are only a few kinds of citrus fruit:
Mandarins are a small, sweet, orange fruit.
Pomelos are also a thing. They’re green and large. They come in sweet or tart. One variety, the Grapefruit, has also historically been called a Pomelo, the way Maize has been called “corn” in the US (“corn” in England means “grain”).
Citrons are a weird little thing that sometimes come in fingered forms, like the Buddha’s hand. They also are the ancestors of lemons.
Then there’s this weird thing called a Papeda which doesn’t matter for the purposes of this article.
But basically there’s four main kinds, and the rest are all hybrids:
Oranges are a larger variety of Mandarin, and while they may have included Pomelo in their history, they are sweet like Mandarins.
Tangerines are basically a type of Mandarin, but a bit more reddish. They taste about the same as a mandarin.
Clementines are basically seedless mandarins.
Basically, fancy Japanese mandarins.
A tangelo is a tangerine mixed with a grapefruit.
This is basically just an orange, but creepy looking.
This is a tangerine mixed with an orange. I don’t know why you’d mix a tangerine with an orange, but they did, and it’s called a Tangor.
All of the above fruits basically taste the same; individual cultivars range from tart to sweet, and most out-of-season orange-like fruits taste bland anyway because of the way they’re picked unripe and shipped across the country. You do NOT want to substitute between the numerous types of orange-colored citrus and lemons and limes, but any of the orange-colored citrus fruits can be freely substituted in a recipe. I personally prefer the smaller hybrids, as they tend to be sweeter.
A size comparison can be found here.
Bonus fact: Fennel and Anise are also very similar plants, except you only eat the seeds of Anise usually, so if you’re looking for Fennel bulbs, stalks, or fronds and you see Anise bulbs, that’s the right thing to buy.