Leonard Cohen famously sang about oranges that came from China in his 1967 debut single, Suzanne.
It turns out the Canadian singer was right about the provenance of the sweet orange (distinct from its cousin, the bitter orange), which emerged in China at least 2,500 years ago.
But the story is a bit more complicated as, like most citrus fruit, the orange is actually a hybrid.
“There is no such thing as a wild orange in China,” botanist David Mabberley, adjunct professor at Macquarie University and author of Citrus: A World History, tells ABC Radio National’s Blueprint for Living.
“It’s a hybrid between two different species: the wild mandarin from southern China and the pomelo, the very large citrus fruit, which is originally native to Indochina.”
It’s easy to dismiss citrus fruits like oranges and mandarins as little more than lunch box fillers.
But the citrus genus has a surprising history, popping up everywhere from ancient Rome and the Renaissance to naval exploration and Casanova’s famed romantic trysts.
Common citrus ancestors
The history of citrus dates back to prehistoric times, when the Gondwanan supercontinent split apart more than 100 million years ago.
However, plotting the citrus family tree, with its many intersections, is difficult thanks to a scant fossil record.
“Fruits don’t make good fossils. There are leaf impressions and wood but, unfortunately, interpreting these things is very, very difficult, because they could represent quite different things,” Professor Mabberley says.
Native to Australia, the finger lime (Citrus australasica) is now grown as a commercial crop. (ABC News: Isabella Higgins)
Most common citrus fruits we know today — oranges, lemons, limes and grapefruit — are hybrids of three main species: mandarin oranges, pomelos and citrons.
This includes the grapefruit (a sweet orange crossed with the pomelo); the lemon (a citron and bitter orange hybrid originally from north-eastern India) and the lime (the most common commercial species, the Persian or Tahitian lime, is a hybrid of the key lime and citron).
While all commercial citrus varieties derive from Asia, Australia boasts a range of native species thanks to its geographic isolation and variety of habitats.
Native Australian varieties include the desert lime (Citrus glauca) from Australia’s arid interior; the Kakadu lime (Citrus gracilis), a species native to the eucalypt woodlands of the Northern Territory; and the finger lime (Citrus australasica), found in the subtropical rainforest of the east coast.
Until recently, many of these citrus varieties were misclassified as other species.
“[We now know that] Australia is the country with the most wild species of citrus,” Professor Mabberley says.
“We have seven or possibly even eight native species in this country, whereas in China, they have only five.”
Citrus in art and religion
The first citrus varieties to arrive in the Mediterranean from Asia were the citron and the lemon, both prized by the ancient Romans.
Muslim traders introduced other citrus varieties including sour oranges, pomelos and limes to Africa and Europe in the 10th century, while the sweet orange arrived in Europe in the 15th century.
Befitting its ancient lineage, the citrus genus has taken on symbolic significance in different religions around the world.
In China, pomelos are traditionally eaten during the mid-autumn festival, while in Christianity, orange blossoms are associated with the Virgin Mary.
In Judaism, a bitter, thick-peeled variety of citron (Citrus medica), known in Hebrew as etrog, is traditionally used in ceremonies marking the Feast of the Tabernacles, a harvest festival falling in autumn.
In modern times, the addition of an orange to the traditional Passover Seder plate has come to represent the contribution of women and LGBTQI+ people in the Jewish community.
A dish of eel garnished with a slice of lemon or orange appears on the table pictured in Leonardo da Vinci’s The Last Supper. (Supplied: Wikimedia Commons)
Citrus fruit also figures prominently in the iconography of Renaissance art.
“Hardly any picture of the Last Supper doesn’t have some citrus on the table,” Professor Mabberley observes.
One reason citrus fruit was so popular with artists was their long shelf-life.
“[The fruits] contain large numbers of compounds which are not only insecticidal but also antagonistic to fungi and bacteria,” Professor Mabberley says.
“They can stay fresh for weeks … which is why they figured so much in the art not only of ancient times but also throughout the Renaissance, right up to the modern period.”
During the Renaissance, the fruit came to symbolise wealth and power among the nobility, particularly among the Medici, a political dynasty founded in Tuscany in the 13th century.
A 16th century Florentine wall plaque showing the House of Medici coat-of-arms. (Supplied: Wikimedia Commons)
According to one theory, the five red balls that appear on the House of Medici’s coat of arms represent the blood orange, a citrus variety cultivated throughout Italy.
“The Medici … were famous for collecting and growing a vast array of [citrus trees] in their palaces in Italy, and some of these plants from that period even survive today,” Professor Mabberley says.
By the 17th century, the fashion for growing citrus had extended to Britain and northern Europe, where orangeries — grand greenhouses featuring large amounts of expensive glass — were built to house sun-loving citrus in the cold northern climate.
“Some still survive,” Professor Mabberley says, pointing to The Orangery at London’s Kew Gardens, built in 1761, and Paris’s Musée de l’Orangerie, built by Napoleon in 1852.
However, despite best efforts, citrus cultivation in orangeries largely failed due to the harsh European climate.
“In the end, these orangeries in the north of Europe had to be repurposed. The one at Kew, for instance, is now a café,” Professor Mabberley says.
Treating the scourge of scurvy
Citrus fruit played an important role in naval exploration, too.
Scurvy, a condition caused by vitamin C deficiency, is believed to have killed two million sailors between 1500 and 1800, the period known as the Age of Exploration.
Those afflicted with the illness suffered debilitating symptoms, including lethargy, bone pain and rotting gums. Naval expeditions during this period had a 50 per cent mortality rate.
“Some of the rhetoric in the famous poem, The Rime of the Ancient Mariner, is actually from the hysterical state of mind that people had once they got this disease,” Professor Mabberley says.
While scurvy remained little understood for centuries, some made the connection between the disease and fresh fruit and vegetables, particularly citrus.
For example, Portuguese sailors planted citrus orchards on the island of Saint Helena in the Atlantic Ocean during the 16th century to provide fresh fruit for passing ships.
More British sailors died of scurvy than wartime action in the 18th century. (Getty Images: Duncan1890)
The medicinal properties of citrus became more widely recognised in 1747 when Scottish physician James Lind effectively treated scurvy with oranges and lemons in a clinical trial.
However, it took about 50 years for the Royal Navy to begin issuing lemon juice to its ships as a measure to prevent scurvy, under a policy adopted in 1795.
By the 19th century, British sailors had earned the nickname “limeys” thanks to the introduction of concentrated lime juice to their rations.
Citrus has been valued for other perceived medicinal properties over the centuries.
Thanks to insecticidal compounds found in the peel, it has long been used to repel moths.
And citrus juice has even served as a contraceptive, most famously by 18th-century Italian adventurer and author Giacomo Casanova.
“Casanova, the world’s greatest lover as they say, used orange juice as a spermicide, and although he went around the world probably passing venereal disease to various people, he survived to an old age,” Professor Mabberley says.
It turns out science appears to be on Casanova’s side, to some degree.
“We now know that small doses of lemon juice … are effective as contraceptives,” he says.
Crisis in the citrus industry
Currently the global citrus industry is facing a crisis due to the outbreak of citrus greening disease, a bacterial disease causing fruit drop and tree death.
The disease, also known as HLB, hasn’t yet arrived in Australia but it has been found in Africa, Asia, South America, the US and — worryingly for Australian producers — nearby Papua New Guinea.
In Florida, orange production has fallen 92 per cent in the last 20 years due to the disease and the impact of natural disasters, including hurricanes and flooding.
“The Florida industry is about to collapse completely due to this disease,” Professor Mabberley says.
However, hope rests in native citrus species, which possess natural resistance to the bacteria that causes citrus greening.
Breeding programs adding disease-resistant genes from native species to commercial cultivars are underway.
“Although people resist genetically modified foods, if they want to have orange juice in the future, this may be the only way forward,” Professor Mabberley says.
Blueprint For Living celebrated its tenth and final year in 2024. In 2025, Jonathan Green hosts a new food and ideas program, Every Bite. You can hear it on Saturdays at 11am on ABC Radio National or any time on the ABC listen app from this week.
