Citron is a fragrant citrus fruit, botanically classified as Citrus medica by both the Swingle and Tanaka systems. The designation medica given it by Linnaeus is apparently derived from its ancient name "Median or Persian apple" that was reported by Theophrastus, who believed it to be native to Persia or the land of the Medes; there is no relation to medicinal uses of the fruit. Theophrastus notes its smooth sharp thorns, like those of a pear, the very fragrant but inedible 'apple', which keeps moths from clothes, and the fact that "it bears its 'apples' at all season; for when some have been gathered, the flower of others is on the tree and it is ripening others.... This tree, as has been said, grows in Persia and Media." Citron was the first of the citrus fruits to appear in the Mediterranean Basin.
The fruit's name derives ultimately from Latin, citrus, also the origin of the genus name, and as a result it has many similar names in many European languages, e.g. cederat, cédrat, cedro, etc. A source of confusion is that citron or similar words in French, Hungarian, Finnish, Latvian, the West Slavic languages and all Germanic languages but English are false friends, as they actually refer to the lemon. Indeed, into the 16th century, the English name citron included the lemon and perhaps the lime as well. Most other European languages, from Albanian and English to Spanish, use variants of the Arabic word laymun "limon".
While the lemon or orange are peeled to consume their pulpy and juicy segments, the citron's pulp is dry, containing a small quantity of insipid juice, if any. The main content of a citron fruit is the thick white rind, which adheres to the segments, and cannot be separated from them easily.
Thus, from ancient through medieval times, the citron was used mainly for medical purposes: to combat seasickness, pulmonary troubles, intestinal ailments, and other disorders. The essential oil of the flavedo (the outermost, pigmented layer of rind) was also regarded as an antibiotic. Citron juice with wine was considered an effective antidote to poison, as Theophrastus reported.
Today the citron is used for the fragrance or zest of its flavedo, but the most important part is still the inner rind (known as pith or albedo), which is a fairly important article in international trade and is widely employed in the food industry as succade, as it is known when it is candied in sugar. There is a rising market for the citron in the United States for the use of its soluble fiber found in its thick albedo.
The citron is also used by Jews (the word for it in Hebrew is etrog) for a religious ritual during the Feast of Tabernacles; therefore is considered as a Jewish symbol, and is found on various Hebrew antiques and archeological findings. Citrons used for ritual purposes cannot be grown by grafting branches.
In Iran, the citron's thick white rind is used to make jam; in Pakistan the fruit is used to make jam as well as pickled; in South Indian cuisine, the citron is widely used in pickles and preserves.
In Ayurvedic system of medicine, the fruit juice is used for treating conditions like nausea, vomiting, excessive thirst etc.
The citron fruit is usually ovate or oblong, narrowing towards the stylar end. However, the citron's fruit shape is highly variable, due to the large quantity of albedo, which forms independently according to the fruits' position on the tree, twig orientation, and many other factors. The rind is leathery, furrowed, and adherent. The inner portion is thick, white and fleshy; the outer is uniformly thin and very fragrant. The pulp is usually acidic, but also can be sweet, and even pulpless varieties are found.
Most citron varieties contain a large number of monoembryonic seeds. They are white, with dark innercoats and red-purplish chalazal spots for the acidic varieties, and colorless for the sweet ones. Some citron varieties are also distinct, having persistent styles, that do not fall off after fecundation. Those are usually promoted for etrog use.
Some citrons have medium-sized oil bubbles at the outer surface, medially distant to each other. Some varieties are ribbed and faintly warted on the outer surface. There is also a fingered citron variety called Buddha's hand.
The color varies from green, when unripe, to a yellow-orange when overripe. The citron does not fall off the tree and can reach 8–10 pounds (4–5 kg) if not picked before fully mature. However, they should be picked before the winter, as the branches might bend or break to the ground, and may cause numerous fungal diseases for the tree.
Citrus medica is a slow-growing shrub or small tree that reaches a height of about 8 to 15 ft (2 to 5 m). It has irregular straggling branches and stiff twigs and long spines at the leaf axils. The evergreen leaves are green and lemon-scented with slightly serrate edges, ovate-lanceolate or ovate elliptic 2.5 to 7.0 inches long. Petioles are usually wingless or with minor wings. The flowers are generally unisexual providing self-pollination, but some male individuals could be found due to pistil abortion. The clustered flowers of the acidic varieties are purplish tinted from outside, but the sweet ones are white-yellowish.
The acidic varieties include the Florentine and Diamante citron from Italy, the Greek citron and the Balady citron from Israel. The sweet varieties include the Corsican and Moroccan citrons. Between the pulpless are also some fingered varieties and the Yemenite citron.
The citron tree is very vigorous with almost no dormancy, blooming several times a year, and is therefore fragile and extremely sensitive to frost.
Origin and distribution
Despite the variation among the cultivars, authorities agree the citron is an old and original species. There is molecular evidence that all other cultivated citrus species arose by hybridization among four ancestral types, which are the citron, pomelo, mandarin and papeda.
The citron is believed to be the purest of them all, since it is usually fertilized by self-pollination, and is therefore generally considered to be a male parent of any citrus hybrid rather than a female one.
Today, authorities agree that all citrus species are native to Southeast Asia where they are found wild and in an uncultivated form. The story of how they spread to the Mediterranean has been reported by Francesco Calabrese, Henri Chapot, Samuel Tolkowsky, Elizabetta Nicolisi and others.
The citron could also be native to India where it borders on Burma, and Pakistan where it is found in valleys at the foot of the Himalayas, and in the Indian Western Ghats. It is thought that by the time of Theophrastus, the citron was mostly cultivated in the Persian Gulf on its way to the Mediterranean basin, where it was cultivated during the later centuries in different areas as described by Erich Isaac. Many mention the role of Alexander the Great and his armies as they attacked Persia and what is today Pakistan, as being responsible for the spread of the citron westward, reaching the European countries such as Macedonia and Italy.
The citron is mentioned in the Torah as being required for ritual use during the Feast of Tabernacles (Lev. 23:40). According to this tradition, the Jews brought it back to Israel from their exile in Egypt, where the Egyptologist and archaeologist Victor Loret claimed to have identified it depicted on the walls of the botanical garden at the Karnak Temple, which dates back to the time of Thutmosis III, approximately 3,000 years ago.
Antiquity and religious texts
The citron has been cultivated since ancient times, predating the cultivation of other citrus species.
Thanks to wikipedia.org