1902 Encyclopedia > Ivy


IVY (A. S., Ifig; Germ., Epheu; perhaps connected with apium, amov) is the collective designation of certain species

FIG. 1.—European Ivy (Hedera Helix). Half nat. size, and varieties of Hedera, the important alliances of which are Aralia and Panax, which, with some twenty other

FlG. 2.—Hedera Helix, var. Deltoidea. Half nat. size, less-known genera, constitute the natural order Araliacese. There are fifty species of ivy recorded in modern books, but

FIG. 3.—Fruiting Form of Hedera Helix. Half nat. size.
they may be reduced to three. The European ivy is the Hedera Helix of Linnaeus (figs. 1-3), a plant subject to in-found in the
finite variety in the forms and colours of its leaves, but the tendency of which is always to a three-lobed form when climbing and a regular ovate form of leaf when producing fruit (fig. 3). The African ivy is H. canariensis, Willd. (fig. 4), otherwise known as the Irish ivy, a native of Africa and the adjacent islands. This also varies, but in a less degree than H. Helix, from which its leaves differ in their larger size, rich deep green colour, and a prevailing tendency to

FIG. i. —African Ivy {Hedera canariensis). Half nat. size.
a five-lobed outline. When in fruit the leaves are usually three-lobed, but they are sometimes entire and broadly ovate. The Asiatic ivy is H. colckica, Koch (fig. 5), other-wise known as H. rsegneriana and H. ragusina. This has ovate, obscurely three-lobed leaves of a coriaceous texture and a deep green colour; in the tree or fruiting form the leaves are narrower than in the climbing form, and without any trace of lobes. Distinctive characters are

FIG. 5.'—Asiatic Ivy (Hediera colehica). One-third nat.

also to be
they may be reduced to three. The European ivy is the Hedera Helix of Linnaeus (figs. 1-3), a plant subject to in-found in the appendages of the pedicels and calyx, H. Helix having six-rayed stellate hairs, H. canariensis fifteen-rayed hairs, and H. colehica yellowish two-lobed scales. A revision of the natural order Hederacex by the late Dr B. Seemann will be found in the Journal of Botany, 1864-5-6.
It is of the utmost importance to note the difference

of characters of the same species of ivy in its two con ditions of climbing and fruiting. The first stage of growth, which we will suppose to be from the seed, is essentially scandent, and the leaves are lobed more or less. This stage is accompanied with a plentiful production of the claspers by means of which the plant becomes attached and obtains support. When it has reached the summit of the tree or tower, the stems being no longer able to main-tain a perpendicular attitude fall over and become horizontal or pendent. Coincidently with this change they cease to produce claspers, and the leaves are strikingly modified in form, being now narrower and less lobed than on the ascending stems. In due time this tree-like growth pro-duces terminal umbels of greenish flowers, which are five-divided, with the styles united into a very short one. These flowers are succeeded by smooth black or yellow berries, containing two to five seeds. The yellow-berried ivy is met with in northern India and in Italy, but in northern Europe it is known only as a curiosity of the garden, where, if sufficiently sheltered and nourished, it becomes an exceedingly beautiful and fruitful tree.
It is stated in books that some forms of sylvestral ivy never flower, but a negative declaration of this kind is valueless. Sylvestral ivies of great age may be found in woods on the western coasts of Britain that have apparently never flowered, but this is probably to be explained by their inability to surmount the trees supporting them, for until the plant can spread its branches horizontally in full daylight, the flowering or tree-like growth is never formed. As regards the claspers, respecting which various views prevail, they are veritable roots, as may be proved by planting an ivy in a damp fern case, when the claspers acquire a new character and penetrate the soil and perform all the functions of roots, suggesting that the hard felt-like form in which they appear on old ivy stems is the consequence simply of an arrest of development. We occasionally see ivies on towers completely isolated from the soil through the destruction of their stems. In these cases the claspers penetrate the structure, and in the capacity of roots obtain the needful sustenance, and the plant lives though no longer deriving nourishment from the earth.
A question of great practical importance arises out of the relation of the plant to its means of support. A moderate growth of ivy is not injurious to trees; still the tendency is from the first inimical to the prosperity of the tree, and at a certain stage it becomes deadly. Therefore the growth of ivy on trees should be kept within reasonable bounds, more especially in the case of trees that are of special value for their beauty, history, or the quality of their timber. In regard to buildings clothed with ivy, there is nothing to be feared so long as the plant does not penetrate the substance of the wall by means of any fissure. Should it thrust its way in, the natural and continuous expansion of its several parts will necessarily hasten the decay of the edifice. But a fair growth of ivy on sound walls that afford no entrance beyond the superficial attach-ment of the claspers is, without any exception whatever, beneficial. It promotes dryness and warmth, reduces to a minimum the corrosive action of the atmosphere, and is altogether as conservative as it is beautiful.
The economical uses of the ivy are not of great import-ance. The wood is used by leather cutters to sharpen their knives. From the trunk a resinous substance is obtained called "ivy gum," which is employed for the relief of toothache. The leaves are eaten greedily by horses, deer, cattle, and sheep, and in times of scarcity have proved useful. The flowers afford a good supply of honey to bees ; and, as they appear in autumn, they occasionally make amends for the shortcomings of the season. The berries are eaten by wood pigeons, blackbirds, and thrushes. From all parts of the plant a balsamic bitter may be obtained, and this in the form of hederic acid is the only preparation of ivy known to chemists.
In the garden the uses of the ivy are innumerable, and the least known though not the least valuable of them is the cultivation of the plant as a bush or tree, the fruiting growth being selected for this purpose. The variegated tree forms of H. Helix, with leaves of creamy white, golden green, or rich deep orange yellow, soon prove handsome miniature trees, that thrive almost as well in smoky town gardens as in the pure air of the country, and that no ordinary winter will injure in the least. The tree-form of the Asiatic ivy (H. colchica) is scarcely to be equalled in beauty of leafage by any evergreen shrub known to English gardens, and, although in the course of a few years it will attain to a stature of 5 or 6 feet, it is but rarely we meet with it, or indeed with tree ivies of any kind; but little attention hitherto having been given to this subject. The scandent forms are more generally appreciated, and are now much employed in the formation of marginal lines, screens, and trained pyramids, as well as for clothing walls. A very striking example of the capabilities of the commonest ivies, when treated artistically as garden plants, may be seen in the Zoological Gardens of Amsterdam, where several paddocks are enclosed with wreaths, garlands, and bands of ivy in a most picturesque manner.
The ivies known in gardens number about sixty varieties, the whole of which are figured and described in The Ivy, a Monograph, by Shirley Hibberd, 1872. To cultivate these is an extremely simple matter, as they will thrive in a poor soil and endure a considerable depth of shade, so that they may with advantage be planted under trees. The common Irish ivy is often to be seen clothing the ground beneath large yew trees where grass would not live, and it is occasionally planted in graveyards in London to form an imitation of grass turf, for which purpose it is admirably suited.
The ivy, like the holly, is a scarce plant on the American
continent. In the northern United States and British
America the winters are not more severe than the ivy can
endure, but the summers are too hot and dry, and the
requirements of the plant have not often obtained attention.
In districts where native ferns abound the ivy will be
found to thrive, and the varieties of Hedera Helix should
have the preference, But in the drier districts ivies might
often be planted on the north side of buildings, and, if
encouraged with water and careful training for three or
four years, would then grow rapidly and train themselves.
A strong light is detrimental to the growth of ivy, but this
enhances its value, for we have no hardy plants that may be
compared with it for variety and beauty that will endure
shade with equal patience. (s. H.)

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