1902 Encyclopedia > Olive
Olive (Olea europaea), the well-known plant that yields the olive oil of commerce, belongs to a section of the natural order Oleaceae, of which it has been taken as the type. The genus Olea includes about thirty-five species, very widely scattered, chiefly over the Old World, from the basin of the Mediterranean to South Africa and New Zealand. The wild olive, or oleaster, is a small tree or bush of rather straggling growth, with thorny branches and opposite oblong pointed leaves, dark greyosh-green above and, in the young state, hoary beneath with whitish scales; the small white flowers, with four-cleft calyx and corolla, two stamens, and bifid stigma, are borne on the last years wood, in racemes springing from the axils of the leaves; the drupaceous fruit is small in the wild plant, and the fleshy pericarp, which gives the garden olive its economic value, is hard and comparatively thin. In the cultivated forms the tree acquires a more compact habit, the branches lose their spinous character, while the young shoots become more or less angular; the leaves are always hoary on the under-side, and are generally lanceolate in shape, though varying much in breadth and size in the different kinds. The fruit is subject to still greater alterations of form and color; usually oval or nearly globular, in some sorts it is egg-shaped, in others much elongated; while the dark hue that it commonly assumes when ripe is exchanged in many varieties for violet, green, or almost white. At present the wild olive is found in most of the countries around the Mediterranean, extending its range on the west to Portugal, and eastward to the vicinity of the Caspian, while, locally, it occurs even in Afganistan. An undoubted native of Syria and the maritime parts of Asia Minor, its abundance in Greece and the islands of the Archipelago, and the frequent allusions to it by the earliest poets, seem to indicate that it was there also indigenous; but in localities remote from the Levant it may have escaped from cultivation, reverting more or less to its primitive type. It shows a marked preference for calcareous soils and a partiality for the sea-breeze, flourishing with especial luxuriance on the limestone slopes and crags that often form the shores of the Greek peninsula and adjacent islands.
A. Olea europaea (from nature). B, opened flower; C. vertical section (after Luersses, Med.-Pharm. Botanik, 1882).
The varieties of olive known to the modern cultivator are extremely numerous, - according to some authorities, equaling or exceeding in number those of the vine. In France and Italy at least thirty kinds have been enumerated, but comparatively few are grown to any large extent. None of these can be safely identified with ancient descriptions, though it is not unlikely that some of the narrow leaved sorts that are most esteemed may be descendants of the famed :Licinian" (see below). Italy retains its old pre-eminence in olive cultivation; and, though its ancient Gallic province now excels it in the production of the finer oils, its fast-improving culture may restore the old prestige, The broad-leaved olive trees of Spain bear a larger fruit, but the pericap is of more bitter flavor and the oil of ranker quality. The olive tree, even when free increase is unchecked by pruning, is of very slow growth; but, where allowed for ages its natural development, the trunk sometimes attains a considerable diameter. De Candolle records one exceeding 23 feet in girth, the age being supposed to amount to seven centuries. Some old Italian olives have been credited with an antiquity reaching back to the first years of the empire, or even to the days of republican Rome; but the age of such ancient trees is always doubtful during growth and their identity with old descriptions still more difficult to establish. The tree in cultivation rarely exceeds 30 feet in height, and in France and Italy is generally confined to much more limited dimensions by frequent pruning. The wood, of a yellow or light greenish-brown hue, is often finely veined with a darker tint, and, being very hard and close-grained, is valued by the cabinetmaker and ornamental turner.
The olive is propagated in various ways, but cutting or layers are generally preferred; the tree roots in favorable soil almost as easily as the willow, and throws up suckers from the stump when cut down. Branches of various thickness are cut into lengths of several feet each, and, planted rather deeply in manured ground, soon vegetate; shorter pieces are sometimes laid horizontally in shallow trenches, when, covered with a few inches of soil, they rapidly throw up sucker-like shoots. In Greece and the islands grafting the cultivated tree on the oleaster is a common practice. In Italy embryonic buds, which form small swellings on the stems, are carefully excised and planted beneath, the surface, where they grow readily, these "uovoli" soon forming a vigorous shoot. Occasionally the larger boughs are inarched, and young trees thus soon obtained. The olive is also sometimes raised from seed, the oily pericap being first softened by slight rotting, or soaking in hot water or in an alkaline solution, to facilitate germination. The olives in the East often receive little attention from the husbandman, the branches being allowed to grow freely and without curtailment by the pruning-knife; water, however, must be supplied in long droughts to ensure a crop; with this neglectful culture the trees bear abundantly only at intervals of three or four years; thus, although wild growth is favorable to the picturesque aspect of the plantation, it is to be recommended on economic grounds. Where the olive is carefully cultivated, as in Languedoc and Provence, it is planted in rows at regular intervals, the distance between the trees varying in different "olivettes," according to the variety grown. Careful pruning is practiced, the object being to preserve the flower-bearing shoots of the preceding year, while keeping the head of the tree low, so as to allow the easy gathering of the fruit; a dome or rounded form is generally the aim of the pruner. The spaces between the trees are occasionally manured with rotten dung, or other nitrogenous matter; in France woolen rags are in high esteem for this purpose. Various annual crops are sometime raised between the rows, and in Calabria wheat even is grown in this way; but the trees are better without any intermediate cropping. Latterly a dwarf variety, very prolific, and with green fruit, has come into favor in certain localities, especially in America, where it is said to have produced a crop two or three seasons, after planting. The ordinary kinds do not become profitable to the grower until from five to seven years after the cuttings are placed in the olive ground. Apart from occasional damage by weather or organic foes, the olive crop is somewhat precarious even with the most careful cultivation, and the large untended trees so often seen in Spain and Italy do not yield that certain income to the peasant proprietor that some authors have attributed to them; the crop from these old trees is often enormous, but they seldom bear well two years in succession, and in many instances a luxuriant harvest can only be reckoned upon every sixth or seventh season. The fruit when ripe is, by the careful grower, picked by hand and deposited in cloths or baskets for conveyance to the mill; but in many parts of Spain and Greece, and generally in Asia, the olives are beaten down by poles, or by shaking the boughs, or even allowed to drop naturally, often lying on the ground until the convenience of the owner admits of their removal; much of the inferior oil owes its bad quality to the carelessness of the proprietor of the trees. In southern Europe the olive harvest is in the winter months, continuing for several weeks; but the time varies in each country, and also with the season and the kinds cultivated. The amount of oil contained in the fruit differs much in the various sorts; the pericap usually yields from 60 to 70 per cent. The ancient agriculturists believed that the olive would not succeed if planted more than a few leagues from the sea (Theophrastus gives 300 stadia as the limit), but modern experience does not confirm the idea, and though showing a preference for the coast, it has long been grown far inland. A calcareous soil, however dry or poor, seems best adapted to its healthy development, though the tree will grow in any light soil, and even on clay if well drained; but, as remarked by Pliny, the plant is more liable to disease on rich soils, and the oil is inferior to the produce of the poorer and more rocky ground the species naturally affects. The olive suffers greatly in some years from the attacks of various enemies. A fungoid growth has at times infested the trees for several successive seasons, to the great damage of the plantations. A species of coccus, C. olease, attaches itself to the shoots, and certain lepidopterous caterpillars feed on the leaves, while the "olive-fly" attacks the fruit. In France the olivettes suffer occasionally from frost; in the early part of the last century many trees were cut to the ground by a winter of exceptional severity. Gales and long-continued rains during the gathering season also cause mischief.
The unripe fruit of the olive is largely used in modern as in ancient times as an article of dessert, to enhance the flavor of wine, and to renew the sensitiveness of the palace for other viands. For this purpose the fruit is picked while green, soaked for a few hours in an alkaline ley, washed well in clean water, and then placed in bottles or jars filled with brine; the Romans added amurca to the salt to increase the bitter flavor of the olives, and at the present day spices are sometimes used.
The leaves and bark of the tree are employed in the south, as a tonic medicine, in intermittent fever. A resinous matter called "olive gum," or Lucca gum, formed by the exuding juice in hot seasons, was anciently in medical esteem, and in modern Italy is used as a perfume.
In England the olive is not hardy, though in the southern counties it will stand ordinary winters with only the protection of a wall, and will bear fruit in such situations; but the leaves are generally shed in the autumn, and the olives rarely ripen.
The genus Olea includes several other species of some economic importance. The olive of America, O. Americana, a rather small tree,, growing in the southern parts of the United States, with broadly-lanceolate leaves and compound racemes of small white fragrant flowers, is remarkable for the extreme hardness of its wood, which, resisting ordinary tools, is called devil-wood by the southern lumberers and squatters. O. paniculata is a larger tree, attaining a height of 50 or 60 feet in the forests of Queensland, and yielding a hard and tough timber. The yet harder wood of O. laurifolia, an inhabitant of Natal, is the black ironwood of the South African colonist. The white or yellowish sweet-scented flowers of O. fragrans, a Chinese species, are employed to communicate their aroma t some of the finer teas; the oblong serrated leaves are said to be used for the adulteration of inferior kinds. Some other species of olive furnish hard and close-grained wood, but are not yet of much general interest. At what remote period of human progress the wild oleaster passed under the care of the husbandman and became the fruitful garden olive it is impossible to conjecture;-history and tradition are alike silent regarding the origin of most of the more valued plants of cultivation, and we know little more of the later evolution of the olive than of the remoter genealogies of our present wheat and maize. The frequent reference in the Bible to the plant and its produce, its implied abundance in the land of Canaan, the important place it has always held in the economy of the inhabitants of Syria, lead us to consider that country the birthplace of the cultivated olive. An improved variety, possessed at first by some small Semitic sept, it was probably slowly distributed to adjacent tribes; and, yielding profusely, with little labor, that oily matter so essential to healthy life in the dry hot climates of the East, the gift of the fruitful tree became in that primitive age a symbol of peace and goodwill among the warlike barbarians. At a later period, with the development of maritime enterprise, the oil was conveyed, as an article of trade, to the neighboring Pelasgic and Ionian nation, and the plant, doubtless, soon followed.
Hehn remarks that in the Homeric world, as depicted in the Iliad, olive oil is known only as a luxury of the wealthy,- an exotic product, prized chiefly for its value in the heroic toilet; the warriors anoint themselves with it after the bath, and the body of Patroclus is similarly sprinkled; but no mention of the culture of the plant is made, nor does it find any place on the Achillean shield, on which a vineyard is represented. But, although no reference to the cultivation of the olive occurs in the Iliad, the presence of the tree in the garden of Alcinous and other familiar allusions show it to have been known when the Odyssey was written. Whenever the introduction may have taken place, all tradition points to the limestone hills of Attica as the seat of its first cultivation on the Hellenic peninsula. When Poseidon and Athene contended for the future city, an olive sprang from the barren rock at the biding of the goddess, the patron of those arts that were to bring undying influence to the rising state. That this myth has some relation to the first planting of the olive in Greece seems certain from the remarkable story told by Herodotus of the Epidaurians, who, on their crops failing, applied for counsel to the Delphic oracle, and were enjoined to erect statue to Damia and Auxesia (symbols of fertility) carved from the wood of the true garden olive, then possessed only by the Athenians, who granted their request for a tree on condition of their making an annual sacrifice to Athene, its patron; they thus obeyed the command of the Pythian, and their lands became again fertile. The sacred tree of the goddess long stood on the Acropolis, and, though destroyed in the Persian invasion, sprouted again from the root,-some suckers of which were said to have produced those olive trees of the Academy in an after age no less revered. By the time of Solon the olive had so spread that he found it necessary to enact laws to regulate the cultivation of the tree in Attica, from which country it was probably distributed gradually to all the Athenian allies and tributary states. To the Ionian coast, where it abounded in the time of Thales, it may have been in an earlier age brought by Phoenician vessels; some of the Sporades may have received it from the same source; the olives of Rhodes and Crete had perhaps a similar origin. Samos, if we may judge from the epithet of Aeschylus, must have had the fruitful plant long before the Persian wars. It is not unlikely that the valued tree was taken to Magna Graecia by the first Achaean colonists, and the asser tion of Pliny (quoted from Fenestella), that no olives existed in Italy in the reign of Tarquinius priscus, must be received with the caution due to many statements of that industrious compiler. In Latin Italy the cultivation seems to have spread slowly, for it was not until the consulship of Pompey that the production of oil became sufficient to permit of its exportation. In Plinys time it was already grown abundantly in the two Gallic provinces and in Spain; indeed, in the earlier days of Strabo the Ligurians supplied the Alpine barbarians with oil, in exchange for the wild produce of their mountains; the plant may have been introduced into those districts by Greek settlers in a previous age. Africa was indebted for the olive mainly to Semitic agencies. In Egypt the culture never seems to have made much progress; the oil found in Theban tombs was probably imported from Syria. Along the southern shore of the great inland sea the tree was carried by the Phoenicians, at a remote period, to their numerous colonies in Africa,- though the abundant olives of Cyrene, to which allusion is made by Theophrastus, and the galucous foliage of whose descendants still clothes the rocks of the deserted Cyrenaica, may have been the offspring of Greek plants brought by the first settlers. The tree was most likely introduced into southern Spain, and perhaps into Sardinia and the Balearic Islands, by Phoenician merchants; and, if it be true that old olive trees were found in the Canaries on their rediscovery by mediaeval navigators, the venerable trees probably owed their origin to the same enterprising pioneers of the ancient world. De Candolle says that the means by which the olive was distributed to the two opposite shores of the Mediterranean are indicated by the names given to the plant by their respective inhabitants,-the Greek passing into the Latin olea and oliva, that in its turn becoming the ulivo of the modern Italian, the olivo of the Spaniard, and the olive, Olivier, of the French, while in Africa and southern Spain the olive retains appellatives derived from the Semitic zail or seit; but the complete subjugation of Barbary by the Saracens sufficiently accounts for the prevalence of Semitic forms in that region; and aceytuno (Arab, zeilun), the Andalusian name of the fruit, locally given to the tree itself, is but a vestige of the Moorish conquest. Yielding a grateful substitute for the butter and animal fats consumed by the races of the north, the olive, among the southern nations of antiquity, became an emblem not only of peace but of national wealth and domestic plenty; the branches borne in the Panathenaea, the wild olive spray of the Olympic victor, the olive crown of the Roman conqueror at ovation, and those of the equites at their imperial review alike typified gifts of peace that, in a barbarous age, could be secured by victory alone. Among the Greeks the oil was valued as an important article of diet, as well as for its external use. The Roman people employed it largely in food and cookery,- the wealthy as an indispensable adjunct to the toilet; and in the luxurious days of the later empire it became a favorite axiom that long and pleasant life depended on two fluids, "wine within and oil without." Pliny vaguely describes fifteen varieties of olive cultivated in his day,- that called the "Licinian" being held in most esteem, and the oil obtained from it at Venafrum in Campania the finest known to Roman connoisseurs; the produce of Istria and Baetica was regarded as second only to that of the Italian peninsula. The gourmet of the empire valued the unripe fruit, steeped in brine, as a provocative to the palate, no less than his modern representative; and pickled olives, retaining their characteristic flavor, have been found among the buried stores of Pompeii. The bitter juice or refuse deposited during expression of the oil (called amurca), and the astringent leaves of the tree have many virtues attributed to them by ancient authors. The oil of the bitter wild olive was employed by the Roman physicians in medicine, but does not appear ever to have been used as food or in the culinary art.
In modern ties the olive has been spread widely over the world; and, though the Mediterranean lands that were its ancient home still yield the chief supply of the oil, the tree is now cultivated successfully in many region unknown to its early distributors. Soon after the discovery of the American continent it was conveyed thither by the Spanish settlers. In Chili it flourishes as luxuriantly as in its native land, the trunk sometimes becoming of large girth, while oil of fair quality is yielded by the fruit. To Peru it was carried at a later date, but has not there been equally successful. Introduced into Mexico by the Jesuit missionaries of the 17th century, it was planted by similar agency in Upper California, where it has prospered latterly under the more careful management of the Anglo-Saxon conqueror. Its cultivation has also been attempted in the south-eastern States, especially in Carolina, Florida, and Mississippi. In the eastern hemisphere the olive has been established in many inland districts, which would have been anciently considered ill adapted for its culture. To Armenia and Persia it was known at a comparatively early period of history, and many olive-yards now exist in Upper Egypt, where the cultivation is said to be increasing. The tree has lately been introduced into Chinese agriculture, while in the present generation it promises to become an important addition to the resources of the Australian planter. In Queensland the olive has found a climate specially suited to its wants; in South Australia, near Adelaide, it also grows vigorously; and there are probably few coast districts of the vast island continent where the tree would not flourish. It has likewise been successfully introduced into some parts of the Cape Colony. (C. P. J.)
The above article was written by: Charles Pierpont Johnson; Professor of Botany, Guy's Hospital, 1830-73; collaborated with J. A. Sowerby in The Ferns of Great Britain.