Citrus Fruits

Scientific Name:  Citrus

Family Name:  Rutaceae

Citrus Fruit Pictures

Citrus fruits, which are in the Rutaceae or rue family, are known to everyone; oranges, tangerines, lemons, grapefruits, limes and citrons.  The genus Citrus contains woody perennial plants with evergreen leaves of varying size from shrubs, 6 feet high, to small trees of 15 - 20 feet.  They do best in the mild climates of southern Italy, Sicily, Spain, Greece, Brazil, Mexico and, in the United States, Florida and southern California.  The fruit of plants of the genus Citrus is a special kind of berry called a hesperidium, a term derived from Greek mythology.   Traditionally, oranges were identified with the golden apples that grew in the garden of the Hesperides, in actual fact, probably the Canaries.  The classification of the citrus is complex, and controversial.  It seems right to speak of an "orange type" and a "citron type."  There are many species of the same family, Rutaceae, including Citrus aurantiumCitrus medica, Citrus maxima, Citrus aurantifolia, and many others.

The sweet orange can be ascribed, according to different authorities, to the following species:  Citron aurantium var. dulcis, Citrus aurantium var. vulgaris, or Citrus sinensis.  Unquestionably there are many synonyms for Citrus aurantium depending on the authority and the time of publication; generally Citrus aurantium refers to the sour or bitter orange that may appear in horticultural literature as Citrus vulgaris, Citrus aurantium higardia, Citrus aurantium vulgaris or Citrus amara.  It was brought from Palestine into Italy by the Crusaders.  More resistant to cold than the sweet orange, Citrus sinensis (Citrus aurantium var. dulcis), it is often used as a grafting under-stock, or as an ornamental shrub.  The fruits are virtually inedible because they are sour and very bitter.

To this same group also belong:  the Chinois or China orange (Citrus myrtifolia or Citrus aurantium var. amara, subvar. sinensis); the Mandarin or Tangerine (Citrus reticulata var. nobilis, or Citrus nobilis, or Citrus deliciosa); the Lime or Adam's apple (Citrus aurantium var. limetta, or Citrus aurantifolia); the Bergamot (Citrus aurantium var. bergamia, or Citrus bergamia) which has never been found in the wild state, and is therefore presumed to be cultivated; the Grapefruit or pomelo (Citrus aurantium var. grandis or Citrus grandis, or Citrus decumana, or Citrus maxima).  These varieties of grapefruit appear to be only ornamental plants, while the true, edible form would be the variety uva carpa.

To the "citron type" corresponds another large Linnaean species, Citrus medica, whose prototype is the citron (Citrus medica or Citrus cedra).   This grows around Provence, Nice, near San Remo in Italy, and outside Genoa.   The Lemon (Citrus medica var. limon or Citrus limonum, or Citrus medica var. lumia) also belongs to this group, as does the pear or sweet lemon (Citrus medica var. lumia).  A very good summer drink, lemonade, is made from the juice.  All these varieties, both orange and citron types, can be considered at the level of species, as can be seen by reading the list of synonyms.

A description of each individual fruit may be more enlightening.

The Sweet orange is native to the Far East:  India, China (where it is considered to be a wild fruit), and Indochina.  Its introduction to the Mediterranean region was relatively late; it probably became known to the Romans around the first century A.D., following the conquest of oriental territories by the Roman Empire.  During the expansion of Arab domination the cultivation of the sweet orange became a heritage of the Mediterranean.  Vasco da Gama is said to have brought a root to Portugal.  According to some authorities the word "orange" derives from the Arabic narandj, which comes from the Sanskrit nagarunga meaning "fruit favored by the elephants."  The cultivars of the sweet orange are now very numerous.  Among them are many important American cultivars, notably Valencia, Washington Navel, Hamlin, Pineapple and Homosassa.  Oranges are extensively grown in Florida and California.  In Italy they are distinguished commercially as "blondes" and "blood," while in the United States they are classed as normal, blood and navel.  Among the former, the most usual is the "common blonde," the "Calabrese" or "oval," the "vanilla," "sweet" or "Maltese."  among the blood oranges grown in Europe the best known are the tarocco, the sanguinello, and the moro.   Oranges are commonly used fresh, or as a refreshing drink.  They can also be made into a little-known salad: the orange segments are seasoned with oil, vinegar, and pepper and a little curry powder, and served with watercress.  Oranges have a high vitamin value, especially vitamin C: 60 mg per 3 1/2 ounces (100 grams) of fruit.   The solid residue is 10%; protein less than 1%; sugars are between 7 and 8%; no lipids are present; 3 1/2 ounces (100 grams) of fruit supply 35 calories.

The fruits of the Bitter orange have no food interests.   But the flowers and leave are highly prized in the cosmetic industry for essences and perfumes.  The rind is used for the extraction of an essential oil for liqueurs such as curacao.

The Mandarin or Tangerine (Citrus reticulata), native to southern China (Yunnan) and Laos, is eaten almost exclusively as a fresh fruit, but can also be candied or glazed, or used in the preparation of a delicate liqueur.  It is grown in the southern United States (where excellent cultivars include Satsuma, Dancy, Clementine, Kara, Frua, Sweet, and King Orange), and in parts of France.  Those of Nice and Algeria are the most prized.

The "temple orange" is a hybrid between mandarin and orange, with large fruits, soft skin, and a pleasing taste.  The vitamin value of the tangerine, expressed in vitamin C, is approximately one-third of that of the orange, and the calorific value is also lower: 7 - 8 calories per 3 1/2 ounces (100 grams) of fruit.   The tangerine contains more water than the orange, and the percentage of carbohydrates is distinctly lower.

The Lime (Citrus aurantifolia), a small fruit tasting rather like the citron or the lemon, is mostly used candied or for summer drinks.   The Bergamot is inedible and grown for the essence extracted from the rind, which is the basis for many perfumes.  In Calabria, Italy, the bergamot is widely cultivated.  Tahiti and Key are two outstanding American cultivars.

Grapefruit grows extensively in the United States, and its cultivation is successfully expanding in many climatically suitable areas, particularly Israel, Greece, Spain and Brazil.  The fruit, spherical or globose, can reach up to 5 1/2 inches in diameter.  The pulp is juicy with an agreeable bitter taste.  It can be eaten fresh, or used in the preparation of an excellent juice.  In Europe and America grapefruits are often served at the start of a meal.  They are very good when sprinkled thickly with brown sugar and grilled.  Excellent cultivars grown in North America are Marsh, Ruby, Duncan, Thompson (pink), and Foster.

The species or variety name of the Citron, Medica, does not indicate medicinal qualities; it means "coming from Media."  The two cultivars that are most known and widespread near the Mediterranean are the Calabria citron with wrinkled peel, and the Florence citron.  Diamante, Corsican, and Etron are common American varieties.  An essential oil used for liqueurs, perfumes and medicines is obtained by distillation of the rind.

The Mediterranean regions provide the best conditions for growth of the Lemon, which is originally from the Far East.  In Italy the production of lemons is concentrated in the traditional citrus-growing regions:  Sicily, Calabria and Piana di Metaponto.  As well as the citron, the lemon is also grown in the Sorrento peninsula and around the northern Italian lakes, especially the Garda, and in the United States extensively in Florida, Texas, and California.  Among the best known cultivars are the very popular "common," the monachello or "little monk," the spadafora, and, as a curiosity, the "Turk's Head" with very large fruits, the size of a man's head, having sweet pulp and juice.  American cultivars are Eureka, Lisbon, Meyer, and Villa Franca.  There are many culinary uses for the lemon, of which both the peel and the juice are used.  The high amount of vitamin C, 60 mg per 3 1/2 ounces (100 grams) of fruit, is also a known fact.  Less known, perhaps, is that the peel is not only a flavoring and a stimulant of the appetite, but also an antibacterial because of its content in essential oil, so that it is considered as a medicinal plant.  Another little-known but highly recommended use, in the opinions of some people, is to rub the teeth and gums with a lemon slice.  This has an astringent and hardening action on the gums and a whitening effect on the teeth.   Lemons are also used in lemonade, sherbets, ice cream, and to heighten the taste of sea food.

The Kumquat (Citrus japonica or Fortunella margarita in honor of Robert Fortune who introduced it to Europe) has not been found in the wild state; it is said to be native to China, and has been cultivated for a long time in China, Japan, Indochina and Java, while it was only later that it was introduced into the Mediterranean basin, America, and Australia.  There is a variety with round fruits (var. maduerensis or Limonella madurensis) called narum by Japanese, and another with oval fruits (var. margarita or Citrus margarita) called nagami.  Its rind is very aromatic, sweet and edible, and the fruits are eaten whole, fresh or candied or preserved in alcohol like cucumbers or pickles.   It is a perfect garnish for roast duck.

In the "citron type," Citrus Medica (Citrus cedra) is the type species or prototype.  Also grouped within this category is the true lemon, Citrus limon (Citrus medica acida, Citrus medica limon) and the pear or sweet lemon, Citrus medica limia.  Among other citrus fruits there are the hybrids; temple (sweet orange and mandarin), tangelo (mandarin x grapefruit: pomelo) and citrange (sweet orange x trifoliate orange, Poncirus trifoliate) and lastly the kumquat (Fortunella Margarite or Citrus japonica).

The areas of greatest citrus fruit production in the world are California, Florida, the southern states of America in general, some areas of Latin America and South Africa, and all the Mediterranean countries.

A curious aspect of citrus plants is provided by the so-called "freaks," first observed in a Florentine garden in 1640.  These citrus plants whose leaves, flowers, and fruits have characteristics varying between the orange and the lemon: lemons with orange skins or vice versa, alternate segments of orange or of lemon.  They are "chimeras" or graft hybrids in which there is a kind of fusion of the tissues of the two species.  [Bianchini, Francesco, Corbetta, Francesco, Pistoia, Marilena, The Complete Book of Fruits and Vegetables, United States Translation: Crown Publishers, New York, 1976; Originally published in Italy as I Frutti della Terra, Arnoldo Mondadori Publisher, Italy, 1973]

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