Are tangerines, satsumas and 'clementinies' any better than the traditional orange?

As much a part of the traditional Christmas food treats as turkey and mince pies, we stuff them into children's stockings and pile them up in large bowls, gleaming and golden. They have for some time been one of the simple and ever-present pleasures of the festive season.

And when you dig your nails into their loose skin and peel it off to find the segments that pull apart so easily, the very scent they exude – the "fragrant mist" described by 5th-century Chinese poet Liu Hsun – is forever evocative, somehow, of the warm glow of log fires and candlelight. And then comes the taste: sweet, refreshing, aromatic.

Psychologically and physically, they come into our shops and markets just when we most need them, after the apples and pears of autumn have waned, ready to replenish our vitamin C levels during the darkest days of mid-winter: "For me, they are simply a taste of sunshine at a bleak time of year,'' enthuses writer Adam Leith Gollner, author of The Fruit Hunters, published earlier this year. "One of my most favourite things is to peel one whole and hold it up to the light; it is as though the sunshine is filtering through it.''

We are talking here, of course, about the satsuma...or should that be the clementine? And whatever happened to the tangerine? And let's not forget the tangelo, the clemenule, the kishu, the minneola, or any one of a number of dozen upon dozens of different varieties and hybrids of the mandarin orange.

Perhaps it is best not to get too obsessed about all the variants because, as Leith Gollner says, some people have gone slightly mad trying to track down and taste every single hybrid. For the record, the Citrus Variety Collection of the University of California, which has one of the biggest archives of its type in the world, has 167 varieties. And as to why some have seeds and some don't, that is all down to the sex life of the citrus fruit.

Shunning such lyrical descriptions of sunshine and fragrant mists, the supermarkets and wholesalers lump them together as "easy peelers". Although you won't see that description on supermarket shelves it is a perfectly accurate one, as the loosely attached skin is the principle characteristic that distinguishes this group of citrus fruits from their relatives – the other oranges, lemons, limes etc.

Add the ability to break up easily into bite-size segments, their small, convenient size, their sweetly seed-free child-friendliness, together with their relative cheapness, and you have a consumer product that is so good that if it didn't exist you might have to invent it. Which is more or less what has happened, by a combination of demand and nature.

Once it was just about Christmas. But long gone are the days when tangerines – actually not a recognised variety at all, but more of that later – appeared for just a couple of weeks around Christmas, sometimes in boxes with fancy foil and tissue wrappings, and then disappeared for another year.

The winter months remain the peak season, when the 'easy peelers' fill the gap on the supermarket shelves after the glut of late summer and autumn fruits and, along with all the other oranges, are much better value than other imported fruits. Equally important, they keep well, enjoying a longer life both on supermarket shelves and in our homes than many other fruits.

A combination of hybrids designed to fruit both early and late, and the development of big, commercially minded exporting combines in Turkey, Morocco and southern Spain, have extended the season from October well into early spring. As Mike Knowles, editor of the trade magazine Eurofruit, says: "Easy peelers are a no-brainer at this time of year. They are accepted as a traditional fruit, people are happy to bring a bowl to the table, and they fit in with ideas of healthy eating, particularly for children.''

And, although in much smaller numbers, southern hemisphere imports keep them on many supermarket shelves throughout the year. Marketing them as lunchbox-friendly healthy eating for children helps ensure demand. Consumption overall rose exponentially during the 1990s and the early part of this decade and has continued upwards, rising by about 15 per cent over the past three years.

We now eat vast quantities of them each year. According to market researchers TNS Worldpanel, during 2008 we spent around £324m on 'easy peelers', eating more than 180m kg of them; they were included in the shopping baskets of almost 80 per cent of households. The bulk of the sales – more than a third by weight – take place in the last three months of the year, when we typically spend a total of £98m on these orange delights. An overwhelming majority of the fruit sold – a total of about 157m kg – are either satsumas or clementines, with clementines leading the way, accounting for almost two thirds of the total.

Satsuma consumption has lost ground in recent years (from 67m kg to 51m kg between 2004 and 2007, although recovering somewhat to 56m last year). Its sweeter rival, the clementine, has overtaken it (rising from 57m kg in 2004 to 101m kg last year). The drop in demand, mirrored in other countries, has resulted in a fewer satsuma trees being planted in the growing regions, putting in jeopardy levels of supply to Britain, which remains the biggest market for the slightly blander, paler satsumas.

The decline is such that Tesco has launched a 'Save our Satsumas' campaign, claiming that British children prefer satsumas because their taste is not as rich – which may well be the first case in history of children rejecting something for being too sweet.

So, how do you distinguish between a tangerine and a clementine, between a satsuma and an ordinary mandarin? Essentially, they are all hybrids of the mandarin (Citrus reticulata), a type of orange whose name stems from a Portuguese derivative of the Malay word for counsellor (matri) – which is also used to refer to senior civil servants.

Interestingly, it is now believed that mandarins may have been the original orange and along with citrons (related to lemons) and pummelo (a type of grapefruit ) were the three primordial varieties from which all the other varieties of citrus fruits – lemons, limes, sweet and sour oranges etc – later derived.

What is known is that mandarins were first cultivated from wild Indian varieties in ancient times in southern China. The kishu/tiny tangerine/clementiny (see panel) may also be the same small mandarin variety that, according to the Oxford Companion to Food, "fashionable Chinese women would hold in their hands so that they were scented by it".

Compared to other fruits and vegetables from the Orient, mandarins were late arrivals in the West. It was not until 1805 that the first ponkan cultivars – a paler, mild flavoured version which is still the most common mandarin variety globally – reached England. From here they spread rapidly to Italy and then the rest of the Mediterranean. They did not reach America until the 1840s, but soon became a staple fruit grown in Florida and California. While the name tangerine was common in Britain by the end of the 19th century, in the United States tangerine is the name used for other, darker varieties which are different to those sold in Europe and which used also to be referred to on the American market as 'Christmas oranges'.

About this time, the richer-flavoured clementine is believed to have been developed in Algeria. Meanwhile, the mostly seedless satsuma was bred in Japan in the 16th century; some now regard is as a separate species, as it is more tolerant of cold than other citrus varieties.

As well the many varieties of satsuma, clementine etc that now exist, all developed by individual growers and breeders, there are the more obscure hybrids. The temple orange was a type of tangor, an incestuous cross between a mandarin and other oranges. The ortanique is the tangor most commonly sold in Britain. Meanwhile, a tangelo is a mandarin-grapefruit hybrid, the best-known version being a minneola – a rich and juicy fruit with a distinctive knob on the stem end, which appears on British supermarket shelves in the early spring. The even more knobbly Ugli fruit is a type of tangelo.

For "easy peeler" producers, one of the keys to a successful fruit is the amount of seeds – lack of seeds being a clear incentive to consumers. But the sex life of the citrus fruit is a complicated matter and, while, in laymen's terms, the in-breeding of some varieties has rendered them "self-incompatible", they can still produce seedless fruit.

However, some will produce fruit with many seeds if they are planted anywhere near seeded varieties. The clementine is not one of these, and the consumer desire for seedless fruit is therefore now pushing the seedless varieties of clementine, which the farmer finds easier to grow, towards world domination.

But seeds or no seeds, satsuma or clementine, tangerine or tangelo, there remains an elemental quality uniting all these fruits in our minds. It is an elusive matter, but somehow they combine an integral symbolism of the festive season, where they revive memories of excited Christmas mornings for even the most jaded of adults, with an ability to deliver a taste of warm sunshine onto our chilled winter palates.

Small wonder: What is a 'clementiny'?

Earlier this month, Tesco launched the 50p-sized clementiny, describing it as "small, rich tasting, easy to peel, great for kids" etc.

The supermarket chain dubbed the clementiny "the world's smallest citrus fruit" – a claim happily reproduced by some newspapers but which is inaccurate. As it happens, the Citrus Variety Collection of the University of California, has a citrus fruit in its collection that is no bigger than a pea.

When this was pointed out to Tesco by The Independent, the retailer eventually amended the description to "the world's smallest easy peeler" – which is not quite the same thing.

The clementiny is actually the same fruit as the 'tiny tangerine' which Marks & Spencer has sold for several years in this country, packaged in a plastic container as a premium product.

Although giving it different names, the two chains agree that this under-sized fruit has been grown in southern China for about 1,300 years (allegedly it was once reserved for the imperial court). According to M&S, they were first spotted by one of its own buyers in the region. In the Tesco version of events, it was a Swiss businessman who first imported it to Europe.

M&S, with its 'tiny tangerine', slightly distorts history to get the desired snappy marketing name. The name tangerine did not originate in China but derives from the Moroccan port of Tangiers, from which large quantities of mandarins were first exported to Britain.

Fruit expert Adam Leith Gollner thinks the tiny tangerine/clementiny is actually a kishu – which probably explains why the marketing people had to come up with a new name. Just to complicate matters further, M&S also offers 'baby clementines' – which are nothing more than selected smaller fruit from the normal clementine crop.