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Citron

life science Maturity 5-7 Next article →

The citron, known scientifically as *Citrus medica*, is a large and highly fragrant citrus fruit. It is distinguished by a thick, coarse rind that sets it apart from many other citrus varieties. While it may resemble a lemon, the citron is generally much larger in scale. This fruit holds a vital place in botanical history because it is one of the original citrus species. Through processes like natural hybrid speciation or artificial hybridization, the citron helped create many other citrus types. In fact, the citron often serves as the male parent in these citrus crosses. This makes it a foundational ancestor for many fruits we eat today, such as lemons and various limes.

Zitronatszitrone
Zitronatszitrone

The anatomy of a citron is quite unique compared to other fruits. The rind is leathery, furrowed, and adheres closely to the fruit. Inside this rind is a very thick, white, and hard layer called the albedo. The outermost layer of the rind is thin and carries an extremely powerful fragrance. The inner pulp can vary greatly; it may be highly acidic, quite sweet, or in some varieties, almost entirely pulpless. The fruit's shape is also highly variable due to how the albedo forms. It can be ovate, oblong, or even ribbed and warted. Some specific varieties, such as the "Buddha's hand," feature long, finger-like segments.

Buddhahand2
Buddhahand2
A species of citrus fruit (Citrus sarcodactylis Hort. Bog.); Wellcome V0042687
A species of citrus fruit (Citrus sarcodactylis Hort. Bog.); Wellcome V0042687
Buddhahand2
Buddhahand2

Biological studies show that all citron cultivars are closely related genetically. Scientists use genetic analysis to divide these cultivars into three distinct clusters. One cluster is Mediterranean in origin and is thought to have come from India. The other two clusters are predominantly found in China. One of these Chinese clusters represents the fingered citron varieties, while the other consists of non-fingered types. The citron tree itself is a vigorous, evergreen shrub or small tree. It features long spines at the leaf axils and lemon-scented leaves. Because the tree has almost no dormancy and blooms several times a year, it is extremely sensitive to frost.

The history of the citron stretches back thousands of years. Archaeological evidence suggests the fruit was cultivated in Sumer as early as the 3rd millennium BC. An Egyptologist named Victor Loret identified depictions of the fruit at the Karnak Temple, dating back approximately 3,500 years to the time of Thutmosis III.

Segment of synagogue mosaic floor from Tiberias at Eretz Israel Museum in Tel Aviv
Segment of synagogue mosaic floor from Tiberias at Eretz Israel Museum in Tel Aviv

Ancient writers also documented its many uses. The Greek philosopher Theophrastus noted that the fruit and leaves were so fragrant they could repel insects and keep clothes smelling fresh. He also suggested the fruit could be used to improve breath. The Roman writer Pliny the Elder called the tree the "Assyrian" tree. He noted that while some people disliked the bitter smell, others esteemed it highly. He even recorded that the pips were used in the East to season ragouts and sweeten the breath.

Citron Balady Etrog Simanim
Citron Balady Etrog Simanim
Segment of synagogue mosaic floor from Tiberias at Eretz Israel Museum in Tel Aviv
Segment of synagogue mosaic floor from Tiberias at Eretz Israel Museum in Tel Aviv

While its scientific name *Citrus medica* suggests an origin in Media, researchers believe this is not entirely accurate. The name likely comes from an old belief that the fruit originated in the kingdom of the Medes. Instead, the citron is thought to have been native to the southeast foothills of the Himalayas. It was likely cultivated along the shores of the Caspian Sea as it moved toward the Mediterranean basin. Some historians suggest that the armies of Alexander the Great helped spread the fruit westward into Greece and Italy.

Citron Balady Etrog Simanim
Citron Balady Etrog Simanim

Today, the citron remains culturally significant in many different ways. In Judaism, the fruit is known as an Etrog and is essential for the harvest holiday of Sukkot. It is often paired with lulavim, which are date palm fronds, during religious rituals. In other parts of the world, the citron is used for its culinary and medicinal properties. For example, Dutch merchants import a candied variety called Succade from Indonesia. This specific variety, *Citrus medica* 'Macrocárpa', can reach a massive weight of 2.5 kilograms. To remove its natural bitterness, the thick albedo undergoes a salt treatment before being processed into confectionery.

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🖼️ Images & Media (6)
File:Map of inferred original wild ranges of the main Citrus cultivars, and selected relevant wild taxa (Fuller et al., 2017).png
Map of inferred original wild ranges of...
File:Segment_of_synagogue_mosaic_floor_from_Tiberias_at_Eretz_Israel_Museum_in_Tel_Aviv.jpg
Segment_of_synagogue_mosaic_floor_from_Tib...
File:A species of citrus fruit (Citrus sarcodactylis Hort. Bog.); Wellcome V0042687.jpg
A species of citrus fruit (Citrus...
File:Zitronatszitrone.jpg
Zitronatszitrone.jpg
File:Citron Balady Etrog Simanim.jpg
Citron Balady Etrog Simanim.jpg
File:Buddhahand2.jpg
Buddhahand2.jpg
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