ORANGE TREE (Citrus Aurantium). The plant that produces the familiar fruit of commerce is closely allied to the citron, lemon and lime, all the cultivated forms of the genus Citrus being so nearly related that their specific demarcation must be regarded as somewhat doubtful and indefinite. The numerous kinds of orange chiefly differing in the external shape, size and flavour of the fruit may all probably be traced to two weU-marked varieties or sub-species - the sweet or China orange, var. sinensis, and the bitter orange or bigarade, var. amara.
The Bitter Seville or Bigarade Orange, C. Aurantium, var. amara (C. vulgaris of Risso), is a rather small tree, rarely exceeding 30 ft. in height. The green shoots bear sharp axillary spines, and alternate evergreen oblong leaves, pointed at the extremity, and with the margins entire or very slightly serrated; they are of a bright glossy green, tint, the stalks distinctly winged and) asin the other species, articulated with the leaf. The fragrant white or pale pinkish flowers appear in the summer months, and the fruit, usually round or spheroidal, does not perfectly ripen until the following spring, so that flowers and both green and mature fruit are often found on the plant at the same time. The bitter aromatic rind of the bigarade is rough, and dotted closely over with concave oil-ceUs; the pulp is acid and more or less bitter in flavour.
The Sweet or China Orange, including the Malta or Portugal orange, has the petioles less distinctly winged, and the leaves more ovate in shape, but chiefly differs in the fruit, the pulp of which is agreeably acidulous and sweet, the rind comparatively smooth, and the oil-cells convex. The ordinary round shape of the sweet orange fruit is varied greatly in certain varieties, in some being greatly elongated, in others much flattened; while several kinds have a conical protuberance at the apex, others are deeply ribbed or furrowed, and a few are distinctly " horned " or lobed, by the partial separation of the carpels. The two subspecies of orange are said to reproduce themselves infallibly by seed; and, where hybridizing is prevented, the seedlings of the sweet and bitter orange appear to retain respectively the more distinctive features of the parent plant.
Though now cultivated widely in most of the warmer parts of the world, and apparently in many completely naturalized, the Orange (Citrus Aurantium, var. amara), from nature, about onethird natural size, a, diagram of flower.
diffusion of the orange has taken place in comparatively recent historical periods. To ancient Mediterranean agriculture it was unknown; and, though the later Greeks and Romans were familiar with the citron as an exotic fruit, their " median apple " appears to have been the only form of the citrine genus with which they were acquainted. The careful researches of Gallesio have proved that India was the country from which the orange spread to western Asia and eventuaUy to Europe. Oranges are at present found wild in the jungles along the lower mountain slopes of Sylhet, Kumaon, Sikkim and other parts of northern India, and, according to Royle, even in the Nilgiri Hills; the plants are generally thorny, and present the other characters of the bitter variety, but occasionally wOd oranges occur with sweet fruit; it is, however, doubtful whether either sub-species is really indigenous to Hindustan, and De CandoUe is probably correct in regarding the Burmese peninsula and southern China as the original home of the orange. Cultivated from a remote period in Hindustan, it was carried to south-western Asia by the Arabs, probably before the 9th century, towards the close of which the bitter orange seems to have been well known to that people; though, according to Mas'udI, it was not cultivated lq Arabia itself until the beginning of the 10th century, when it was first planted in 'Oman, and afterwards carried to Mesopotamia and Syria. It spread ultimately, through the agency of the same race, to Africa and Spain, and perhaps to Sicily, following everywhere the tide of Mohammedan conquest and civilization. In the 12th century the bigarade was abundantly cultivated in all the Levant countries, and the returning soldiers of the Cross brought it from Palestine to Italy and Provence. An orange tree of this variety is said to have been planted by St Dominic in the year 1200, though the identity of the one still standing in the garden of the monastery of St Sabina at Rome, and now attributed to the energetic friar, may be somewhat doubtful. No allusion to the sweet orange occurs in contemporary Uterature at this early date, and its introduction to Europe took place at a considerably later period, though the exact time is unknown. It was commonly cultivated in Italy early in the 15th century, and seems to have been known there previously to the expedition of Da Gama (1497), as a Florentine narrator of that voyage appears to have been famiUar with the fruit. The importation of this tree into Europe, though often attributed to the Portuguese, is with more probability referred to the enterprise of the Genoese merchants of the 15th century, who must have found it growing abundantly then in the Levant. The prevailing European name of the orange is suflicient evidence of its origin and of the Une taken in its migration westward. The Sanskrit designation nagrungo, becoming narungec in Hindustani, and corrupted by the Arabs into ndranj (Spanish naranja), passed by easy transitions into the Italian araiicia (Latinized aurantium), the Romance arangi, and the later Provengal orange. The true Chinese variety, however, was undoubtedly brought by the Portuguese navigators direct from the East both to their own country and to the Azores, where now lu.xuriant groves of the golden-fruited tree give a modern realization to the old myth of the gardens of the Hesperides.^ Throughout China and in Japan the orange has been grown from very ancient times, and it was found diffused widely when the Indian Archipelago was first visited by Europeans. In more recent days its cultivation has extended over most of the warmer regions of the globe, the tree growing freely and producing fruit abundantly wherever heat is sufficient and enough moisture can be supplied to the roots; where night-frosts occur in winter or spring the culture becomes more difficult and the crop precarious.
The orange flourishes in any moderately fertile soil, if it is well drained and sufficiently moist; but a rather stiff loam or calcareous marl, intermingled with some vegetable humus, is most favourable to its growth. Grafting or budding on stocks raised from the seed of some vigorous variety is the plan usually adopted by the cultivator. The seeds, carefuUy selected, are sown in well-prepared ground, and the seedUngs removed to a nursery-bed in the fourth or fifth year, and, sometimes after a second transplantation, grafted in the seventh or eighth year with the desired variety. When the grafts have acquired sufficient vigour, the trees are placed in rows in the permanent orangery. Propagation by layers is occasionally adopted; cuttings do not readily root, and multipKcation directly by seed is always doubtful in result, though recommended by some authorities. The distance left between the trees in the permanent plantation or grove varies according to the size of the plants and subsequent culture adopted. In France, when the trunks are from 5 to 65 ft. in height, a space of from 16 to 26 ft. is left between; but the dwarfer trees admit of much closer planting. In the West Indies and Azores an interval of 24 or even of 30 ft. is often allowed. The ground is kept well stirred between the trunks, and the roots manured with well-rotted dung, guano or other highly nitrogenous matter; shallow pits are sometimes formed above the roots for the reception of Uquid or other manures; in dry climates water must be abundantly and frequently supphed. The trees require regular and careful pruning, the heads being trained as nearly as possible to a spherical form. Between the rows melons, pumpkins and other annual vegetables are frequently raised. In garden culture the orange is often trained as an espalier, and with careful attention yields fruit in great profusion when thus grown. In favourable seasons the oranges are produced in great abundance, from 400 to 1000 being 1 The modern Arabic name, Bortuljan (that is, Portuguese), shows that the China apple reached the Levant from the West.
commonly borne on a single plant in full bearing, while on large trees the latter number is often vastly exceeded. The trees will continue to bear abundantly from fifty to eighty years, or even more; and some old orange trees, whose age must be reckoned by centuries, still produce their golden crop; these very ancient trees are, however, generally of the bitter variety. Oranges intended for export to colder climates are gathered long before the deep tint that indicates maturity is attained, the fruit ripening rapidly after picking; but the delicious taste of the mature China orange is never thus acquired, and those who have not eaten the fruit in a perfectly ripe state have little idea of its flavour when in that condition. Carefully gathered, the oranges are packed in boxes, each orange being wrapped in paper, or with dry maize husks or leaves placed between them. The immense quantities of this valuable fruit imported into Britain are derived from various sources, the Azores (" St Michael's" oranges), Sicily, Portugal, Spain and other Mediterranean countries, Jamaica, the Bahamas and Florida, California, etc. In Florida the bitter orange has grown, from an unknown period, in a wild condition, and some of the earUer botanical explorers regarded it as an indigenous tree; but it was undoubtedly brought by the Spanish colonists to the West India Islands, and was probably soon afterwards transplanted to Florida by them or their buccaneering enemies; its chief use in America is for stocks on which to graft sweet orange and other species of Citrus.
Orange cultivation has been attempted with success in several parts of Austraha, especially in New South Wales, where the orange groves near Paramatta yield an abundant colonial supply. The orangeries of Queensland and South Australia hkewise produce well. In many of the Pacific Islands the plant has been long estabUshed. There are numerous varieties of the sweet orange, a few of which deserve mention on account of some striking peculiarity. Maltese or Blood oranges are characterized by the deep-red tint of the pulp, and comprise some of the best varieties. Gallesio refers to the blood orange as cultivated extensively in Malta and Provence; they are largely grown in the Mediterranean region in the present day, and have been introduced into America. So-called navel oranges have an umbilical mark on the apex of the fruit due to the production of an incipient second whorl of carpels. Baptiste Ferrari, a Jesuit monk, in his work H esperidcs , siveDe malorum aureorum cuHiira et Jisiis Libri Quatuor, pubhshed at Rome in 1646, figures and describes (pp. 403, 405) such an orange. The mandarin orange of China, sometimes regarded as a distinct species, C. nobilis, is remarkable for its very flat spheroidal fruit, the rind of which readily separates with the shghtest pressure; the pulp has a pecuharly luscious flavour when ripe. The small Tangerine oranges, valued for their fine fragrance, are derived from the mandarin.
Diseases. - Several are caused by fungi, others by insects. Of the fungus diseases that known as foot-rot in Florida and mal-di-gomma in Italy is very widely distributed. It occurs on the lower part of the trunk and the main roots of the tree, and is indicated by exudation of gum on the bark covering the diseased spot. The diseased patches spread into the wood, killing the tissues, which emit a foetid odour; the general appearance of the tree is unhealthy, the leaves become yellow and the twigs and young branches die. A fungus, Fusarium limonis is found associated with the disease, which is also fostered by faulty drainage, a shaded condition of the soil, the use of rank manures and other conditions. For treatment the soil should be removed from the base of the trunk, the diseased patches cut away and the wound treated with a fungicide. Decay of oranges in transit often causes serious losses; this has been shown to be due to a species of PeniciUium, of which the germinating spores penetrate the skin of damaged fruits. Careful picking, handling and packing have much reduced the amount of loss from this cause. Another fungus disease, scab, has been very injurious to the lemon and bitter orange in Florida. It is caused lay a species of Clados pari urn, which forms numerous small warts on the leaves and fruits; spraying with a weak solution of Bordeaux mixture or with ammoniacal solution of carbonate of copper is recommended. The sooty mould of orange, which forms a black incrustation on the leaves and also the fruit, probably occurs wherever the orange is cultivated. It is caused by species of Meliola; in Europe and the United States, by M. Pcnzigii and M. CameUiae. The fruit is often rendered unsaleable and the plant is also injured as the leaves are unable properly to perform their functions. The fungus is not a parasite, but Uves apparently upon the honey-dew secreted by aphides, etc., and is therefore dependent on the presence of these insects. Spraying with resin-wash is an effective preventive, as it destroys the insects. Several insect enemies attack the plant, of which the scale insect Aspidiotiis is the most injurious in Europe and the Azores. In Florida another species, Mylilaspis cilricola (purple scale), sometimes disfigures the fruit to such an extent as to make it unfit for market. Several species of Aleyrodes are insect pests on leaves of the orange; A. citri, the white fly of Florida, is described as the most important of aU the insect pests of the crop in Florida at the present time, and another species, A. Howardi, is a very serious pest in Cuba. Cold weather in winter has sometimes proved destructive in Provence, and many plantations were destroyed by the hard frosts of 1789 and 1820.
Besides the widespread use of the fruit as an agreeable and wholesome article of diet, that of the sweet orange, abounding in citric acid, possesses in a high degree the antiscorbutic properties that render the lemon and Ume so valuable in medicine; and the free consumption of this fruit in the large towns of England during the winter months has doubtless a very beneficial effect on the health of the people. The juice is sometimes employed as a coohng drink in fevers, as well as for making a pleasant beverage in hot weather.
The bitter orange is chiefly cultivated for the aromatic and tonic quahties of the rind, which render it a valuable stomachic. Planted long ago in Andalusia by the Moorish conquerors, it is still extensively grown in southern Spain - deriving its common English name of " Seville " orange from the abundant groves that still exist around that city, though the plant is now largely cultivated elsewhere. The fruit is imported into Great Britain and the United States in considerable quantities for the manufacture of orange marmalade, which is prepared from the pulp and rind, usually more or less mingled with the pulp of the China orange. In medicine the fresh peel is largely employed as an aromatic tonic, and often, in tincture and syrup and " orange wine," as a mere vehicle to disguise the flavour of more nauseous remedies. The chief constituents are three glucosides, hesperidin, isohesperidin and aurantianiarin, the latter being the bitter principle; and an oil which mainly consists of a terpene known as limonene. The essential oil of the rind is collected for the use of the perfumer, being obtained either by the pressure of the fresh peel against a piece of sponge, or by the process known as ecuelle, in which the skin of the ripe fruit is scraped against a series of points or ridges arranged upon the surface of a peculiarly-shaped dish or broad funnel, when the oil flows freely from the broken cells. Another fragrant oil, called in France essence de petit grain, is procured by the distillation of the leaves, from which also an aromatic water is prepared. The flowers of both sweet and bitter orange yield, when distilled with water, the "oil of Neroh" of the druggist and perfumer, and Ukewise the fragrant Hquid known as " orangeflower water," which is a saturated solution of the volatile oil of the fresh flowers. The candied peel is much in request by cook and confectioner; the favourite liqueur sold as "curafoa " derives its aromatic flavour from the rind of the bigarade. The minute immature oranges that drop from the trees are manufactured into "issue-peas"; from those of the sweet orange in a fresh state a sweetmeat is sometimes prepared in France. Orange trees occasionally acquire a considerable diameter; the trunk of one near Nice, still standing in 1780, was so large that two men could scarcely embrace it; the tree was kiUed by the intense cold of the winter of that year. The wood of the orange is of a fine yellow tint, and, being hard and close-grained.
is valued by the turner and cabinetmaker for the manufacture of small articles; it takes a good polish.
Although the bitter " Poma de Orenge " were brought in small quantities from Spain to England as early as the year 1290, no attempt appears to have been made to cultivate the tree in Britain untd about 1595, when some plants were introduced by the Carews of Beddington in Surrey, and placed in their garden, where, trained against a wall, and sheltered in winter, they remained until destroyed by the great frost of 1739-1740. In the 18th century the tree became a favourite object of conservatory growth; in the open air, planted against a wall, and covered with mats in winter, it has often stood the cold of many seasons in the southern counties, in such situations the trees occasionally bearing abundant fruit. The trees are usually imported from Italy, where, especially near Nervi, such plants are raised in great numbers for exportation; they are generally budded on the stocks of some free-growing variety, often on the lemon or citron.
The orange has been usually cultivated in England for the beauty of the plant and the fragrance of its blossoms, rather than for the purpose of affording a supply of edible fruit. The latter can, however, be easily grown in a hot-house, some of the fruits thus grown, especially those of the pretty Httle Tangerine variety, being superior in quaUty to the imported fruit. The best form of orange house is the span-roofed, with glass on both sides, the height and other conditions being similar to those recommended for stove plants. The trees may be planted out, a row on each side a central path, in a house of moderate width. They will flourish in a compost of good, light, turfy loam and welldecayed leaf-mould in equal proportions, to which a little broken charcoal may be added. Each year the trees should be top-dressed with a similar compost, removing some of the old soil beforehand. The trees, if intended to be permanent, should be placed 10 to 12 ft. apart. It wifl often be found more convenient to grow the plants in pots or tubs, and then bottom heat can be secured by placing them on or over a series of hot-water pipes kept near to or above the ground level. The pots or tubs should be thoroughly well drained, and should not be too large for the plants; and repotting should take place about every third year, the soil being top-dressed in intervening years. The temperature may be kept at about 50° or 55° in winter, under which treatment the trees wiU come into bloom in February; the heat must then be increased to 60° or 65° in the day time, and later on to 80° or 85°. Throughout the growing season the trees should be liberaUy watered, and thoroughly syringed everyday; this wiU materially assist in keeping down insects. When the trees are in bloom, however, they must not be syringed, but the house must be kept moist by throwing water on the pathways a few times during the day. When the flowers have fallen the syringe may be used again daily in the early morning and late afternoon. The fruit may be expected to ripen from about the middle of October to January, and if the sorts are good wiU be of excellent quality. When the trees are at rest the soil must not be kept too wet, since this will produce a sickly condition, through the loss of the small feeding roots. The trees require httle pruning or training. The tips of the stronger shoots are just pinched out when they have made about 6 in. of growth, but when a branch appears to be robbing the rest, or growing ahead of them, it should be shortened back or tied down.
When grown for the production of flowers, which are always in great request, the plants must be treated in a similar manner to that already described, but may do without bottom heat.
For details of orange varieties, cultivation, etc., see Risso and Poiteau, Histoire et culture des oratigers (edited by A. Du Breuil, Paris, 1872); for early history and diffusion, G. Gallesio, Traite du citrus (Paris, 1811). A useful modern handbook is Citrus Fruits and their CuUure,hy Harold Hume (New York, 1907).
There are many varieties of the sweet orange that maj "be grown under glass in the British Isles. Amongst the best for dessert is the St Michaels, a heavy cropper with large juicy fruits; and closely related are Bittencourt, Egg, Dom Louise, Sustain, Excelsior and Brown's Orange. The White Orange, so called from its pale skin, is excellent. Silver or Flata is a sweet, pale-coloured variety with a curious weal-like orange stripe, the fruit being rather small but heavy. Embiguu, or the Washinj^lon Navel Orange, produces splendid fruit under glass. The Jafa, with large oblong fruits and large wavy crinkled leaves, although a sliy bearer, makes up for this in the size of its fruits. The Maltese Blood Orange is remarkable for the blood-like stains in the pulp, although these are not present in every fruit even on the same tree.
Other kinds of oranges are the Tangerine with small aromatic fruits and wUlow-like leaves. The Seville orange is a handsome free-flowering tree, but its fruits are bitter and used only for preserving and marmalade.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)