Citron ( Citrus medica ). Shrub of the Rutaceae family cultivated for its fruit, called citron, poncil, French lemon or grapefruit, which is rarely consumed fresh, but its skin is used in pastry preparations and as a flavoring for its strong content of essential oils.
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- 1 Taxonomy
- 1 Scientific name
- 1.1 Authors
- 2 Combinations of this basonym
- 3 Synonymy
- 4 Common name
- 1 Scientific name
- 2 Features
- 1 Climate
- 2 Soil
- 3 Propagation
- 4 Diseases and pests
- 3 Habitat and distribution
- 4 Varieties
- 5 Uses
- 1 Medicinal uses
- 6 References
- 7 Sources
- Citrus medica L.  
- Linnaeus , Carl von
- Published in: Species Plantarum 2: 782. 1753 . (1 May 1753 ) 
Combinations of this basonym
- Aurantium medicum (L.) M. Gómez 
- Aurantium medicum (L.) M. Gómez
- Citreum vulgare Tourn. ex Mill.
- Citrus × aurantium subvar. amilbed Engl.
- Citrus × aurantium subvar. chakotra Engl.
- Citrus × limon (L.) Burm. F.
- Citrus × limon (L.) Osbeck
- Citrus × limon var. digitata Risso
- Citrus × limonia (L.) Osbeck
- Citrus × limonum Risso
- Citrus alata (Tanaka) Tanaka
- Citrus fragrans Salisb.
- Citrus limon (L.) Osbeck
- Citrus medica f. monstrous Guillaumin
- Citrus medica subsp. bajoum H. Perrier
- Citrus medica var. alata Tanaka
- Citrus medica var. digitata Risso
- Citrus medica var. ethrog Engl.
- Citrus medica var. lemon L.
- Citrus medica var. proper Hook. F.
- Citrus medica var. sarcodactylis (Hoola van Nooten) Swingle
- Citrus odorata Roussel
- Citrus sarcodactylis Hoola van Nooten
- Citrus tuberosa Mill.
- Sarcodactilis helicteroides Gaertn. 
- Citrus × aurantium var. bergamia (Risso) Brandis
- Citrus × aurantium var. proper Guillaumin
- Citrus × aurantium var. Tamurana Yu.Tanaka
- Citrus balotina Poit. & Turpin
- Citrus × bergamia subsp. mellarosa (Risso) Rivera, et al.
- Citrus bicolor Poit. & Turpin
- Citrus bigena Poit. & Turpin
- Citrus cedra Link
- Citrus cedrata Raf.
- Citrus crassa Hassk.
- Citrus gongra Raf.
- Citrus grandis var. pyriformis (Hassk.) Karaya
- Citrus hassaku Yu.Tanaka
- Citrus hiroshimana Yu.Tanaka
- Citrus kizu Yu.Tanaka
- Citrus kwangsiensis Hu
- Citrus limetta Risso
- Citrus limetta subsp. murcica S.Ríos & al.
- Citrus × limodulcis Rivera, et al.
- Citrus limonimedica Lush.
- Citrus lumia risso
- Citrus medica var. dulcis Risso & Poit.
- Citrus medica f. lemon (L.) Hiroë
- Citrus medica subsp. limonia (Risso) Hook. F.
- Citrus medica var. limonum (Risso) Brandis
- Citrus medica var. nana Wester
- Citrus medica var. sarcodactylus (Siebold ex Hoola van Nooten) Swingle
- Citrus medica f. sudachi (Shirai) M.Hiroe
- Citrus nana (Wester) Yu.Tanaka
- Citrus pyriformis Hassk.
- Citrus sarcodactylus Siebold ex Hoola van Nooten
- Citrus sudachi Yu.Tanaka [Invalid]
- Limon racemosum Mill.
- Limon spinosum Mill.
- Limon × vulgaris Ferrarius ex Miller 
Citron, citron, poncil, French lemon or grapefruit.
Citrus medica is a small tree or evergreen shrub, 2.5 to 5 m tall, with a twisted stem and dense and rigid branches, with thorns in the leaf axils. The leaves are simple, alternate, elliptical to lanceolate, up to 18 cm long, with a leathery surface and a dark green color on the upper side, with a distinctive lemon fragrance , located at the end of short petioles. It produces hermaphrodite flowers , fragrant, of good size, white or purple, forming small clusters. They have 4 to 5 petals, with 30 to 60 stamens.
The fruit is an oblong or globose hesperidium, rarely pyriform, up to 30 cm in diameter, varying greatly between specimens and even in the same specimen, with a well-marked style. It is covered with a thick, fleshy peel, attached to the endocarp, yellow or green in color, with small oil glands and often rough. It has 10 to 15 carpels, firm, not very juicy, sweet or acid depending on the variety. The seeds are normally small, mono-embryonic, smooth, white inside, and abundant.
The citron tree is very sensitive to frost, it does not go into winter dormancy as early as other citrus species. Foliage and fruit are easily damaged by extreme heat and drought. The best locations for citron are those where there are no extremes of temperature .
The soils where citron is grown vary considerably, but the tree requires good aeration
Citrons grow easily from cuttings taken from 2- to 4-year-old branches and quickly and deeply buried in the soil without defoliation. For faster growth, citron can be grafted onto “rough lemon”, Grapefruit , Sour orange or sweet orange , but the fruits do not reach the size of those produced from cuttings, and the citron tends to make the rootstock grow longer. The “rough lemon” has been found to be too susceptible to gummosis to be used as a citron stock in Colombia . The ‘Etrog’, to be acceptable for ritual use, cannot be grafted.
Diseases and pests
The citron tree is undoubtedly susceptible to most of the pests that attack other citrus species. The citrus bud mite (Eriophyes sheldoni), the citrus mite (Phyllocoptruta oleivora), and the snowshoe (Unaspis citri) are among its main enemies. Florida horticulturists report that Florida citron trees are almost always stunted, subject to gummosis, and generally in a state of decline and dieback, and consequently low producers. Branch knots, caused by the fungus Sphaeropsis tumefaciens, were first noticed in citron trees in Puerto Rico in 1977. By 1983 , it had become a serious threat to the local citron industry. The deformations become large and necrotic, leading to the “witch’s broom”, regressive death and the breaking of the branches.
Habitat and distribution
The origin of Citrus medica is unknown, but domestic seeds have been documented since the 4th millennium BC. C .; probably the army of Alexander the Great introduced it into the basin of the Mediterranean Sea , and its cultivation quickly spread. In ancient Rome it was used first as medicinal, and from the 2nd century on for food purposes; both Dioscorides and Pliny record it. It must have been grown in Judea in Biblical times, since its fruit — called etrog in Hebrew — is one of the ritual species used in the Sukkot festival. In Italy they disappeared with the fall of the Roman Empire, being conserved only in Sicily , Sardinia and the Neapolitan region.
It came to America by way of Spain ; the conquerors introduced it to Florida , Puerto Rico and finally California ; Although commercial plantations were developed, eventually the difficulty of their growth led to their abandonment. In Central America, Brazil and Colombia it has become naturalized, and there are plantations of some extent, especially for export.
Citron cultivars are mainly of two types:
- Those with pink, blossoms buds flowers purple petals and colored purple inside and acidic pulp layer of dark seed.
2. Those that do not have pink or purple coloration in the shoots, nor in the flowers, with non-acid pulp and the inner covering of the colorless seed.
Among the best known cultivars are:
‘Corsica’ unknown origin, but the leading citron of Corsica; introduced to United States about 1891 and apparently California grown variety , ellipsoid or slightly obovate, grooved at the base, large, yellow skin, rough, lumpy, very thick, fleshy; the pulp is crisp, not very juicy, not acidic, with many seeds. Small, broad, moderately thorny tree with some large spines. ‘Diamante’ (‘Cedro Liscio’, possibly the same as ‘Italiana’ and ‘Siciliana’) of unknown origin, but the leading variety in Italyand preferred by processors elsewhere; long-oval or ellipsoid, furrowed at the base, with broad nipples at the apex; yellow, smooth or slightly ribbed skin, very thick, fleshy; crunchy pulp, not juicy, acidic, with many seeds. Small, broad, thorny tree like ‘Córsica’. Very similar to a cultivar called “Earle” in Cuba .
‘Etrog’ (‘Ethrog’, ‘Atrog’; Citrus medica var. Ethrog Engl.) The main variety in Israel , ellipsoid, spindle or lemon- shaped , with moderate neck and often stylized at the base, with prominent nipple at apex; moderately small when harvested, if not picked, they will remain on the tree, continuing to grow for years, until the stem can not support it. For ritual use, the fruit should weigh about 5 ounces (142 g) and not be oblong in shape. The rind is yellow, semi-rough, slightly ribbed, thick, fleshy; the pulp is crisp, firm, with little juice, acidic, with many seeds. The tree is small, not vigorous, leaves rounded at the apex and hollowed out. This cultivation has been the official citron in the Feast of Tabernacles ritual.
‘Fingered Citron’ (‘Buddha’s Hand’, or ‘Buddha’s Fingers’; Citrus medica var. Sarcodactylus Swing.); called Shou Fu in China , bushukon in Japan , limau jari, jeruk tangan, limau kerat lingtang, in Malaysia ; djerook tangan in Indonesia ; som-mu in Thailand ; phât thu in Vietnam . The fruit is corrugated, fully or partially divided into about 5 finger-shaped segments, with little or no pulp, no seeds or with missing seeds. The fruit is very fragrant and is placed as an offering on temple altars. It is grown in China and Japan, they are candied in China. In northwestern India , there are several named types in addition to the ‘fingered’:
Small ‘Bajoura’, with thin skin, lots of acidic juice. ‘Chhangura’ is believed to be a wild form and is often found in its natural state, small, wrinkled fruits with no pulp.
‘Madhankri’ or ‘Madhankri’ large fruits, with sweet pulp.
‘Turunj’ large fruits, with thick skin, the inner part white, sweet and edible; scanty, dry, acidic pulp. The leaves are oblong and notched at the apex.
Citrons are used to make jams and liqueurs. They are grown mainly for their peel, generally candied and used in confectionery. Known in ancient times for its healing properties, I do not consume. In Muslim Spain its candied fruits , citrons, were consumed with sugar , and the nectar resulting from the distillation of its flowers was used to dress table olives . Fruit : In China and Japan people value citron for its fragrance, and it is a common practice in the northand central China carrying a ripe fruit in the hand or placing the fruit on a plate on a table to perfume the air in a room. The nuts are put with stored clothing to repel moths. In southern China, the juice is used to wash fine clothes. Previously, the essential oil from the peel was distilled for use in perfumery.
- Leaves and Branches: On some of the South Pacific islands , “Cedrat Petitgrain Oil” is distilled from the leaves and branches of citron trees for the French perfume industry.
- Flowers: The flowers have been distilled for essential oil, which has limited use in making perfume.
- Wood : The branches of the citron tree are used as canes in India . The wood is white , hard, heavy, and fine-grained. In India, it is used for agricultural implements.
In ancient times and in the Middle Ages , “Etrog” was used as a remedy for seasickness, lung problems, intestinal diseases and other diseases. The juice of the citron with wine was considered as an effective purgative to eliminate poisons from the body . In India , the husk is a remedy for dysentery and is eaten to overcome halitosis . The distilled juice is given as a sedative. Candied peel is sold in China as a stomachic, stimulant, expectorant, and tonic. In tropical west Africa , citron is used only as a medicine, in particular, against rheumatism .
The flowers are used medicinally by the Chinese. In Malaysia , a decoction of the fruit is taken to ward off evil spirits. A decoction of the shoots of wild plants is given to improve appetite, relieve stomach pain , and expel pinworms . The juice of the leaves , along with that of Polygonum and Indigofera is taken after childbirth . An infusion of the leaves is given as an antispasmodic. In Southeast Asia , citron seeds are used as a vermifuge. In panama, ground and combined with other ingredients, and used as an antidote to poisons. The essential oil from the peel is considered an antibiotic