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POPLAR (Lat. Populus)

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Originally appearing in Volume V22, Page 90 of the 1911 Encyclopedia Britannica.
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POPLAR (See also:Lat. Populus) , the name of a small See also:group of catkin-bearing trees belonging to the See also:order Salicaceae. The catkins of the poplars differ from those of the nearly allied willows in the presence of a rudimentary perianth, of obliquely See also:cup-shaped See also:form, within the toothed bracteal scales; the male See also:flowers contain from eight to See also:thirty stamens; the fertile See also:bear a one-celled (nearly divided) ovary, surmounted by the deeply cleft stigmas; the two-valved See also:capsule contains several seeds, each furnished with a See also:long tuft of silky or See also:cotton-like hairs. The leaves are broader than in most willows, and are generally either deltoid or ovate in shape, often cordate at the See also:base, andfrequently with slender petioles vertically flattened. Many of the See also:species attain a large See also:size, and all are of very rapid growth. The poplars are almost entirely confined to the See also:north temperate See also:zone, but a few approach or even pass its See also:northern limit, and they are widely distributed within that See also:area; they show, like the willows, a partiality for moist ground and often See also:line the See also:river-sides in otherwise treeless districts. There are about twenty species, but the number cannot be very accurately defined—several, usually regarded as distinct, being probably merely variable forms of the same type, and the ease with which the trees inter-See also:cross has led to the See also:appearance of many hybrids. All yield a soft, easily-worked See also:timber, which, though very perishable when exposed to See also:weather, possesses sufficient durability when kept dry to give the trees a certain economic value. Many of the species are used for See also:paper-making. Of the See also:European kinds one of the most important and best marked forms is the See also:white poplar or abele, P. See also:alba, a See also:tree of large size, with rounded spreading See also:head and curved branches, which, like the See also:trunk, are covered with a greyish white bark, becoming much furrowed on old stems. The leaves are ovate or nearly See also:round in See also:general outline, but with deeply waved, more or less lobed and indented margins and cordate base; the upper See also:side is of a dark See also:green tint, but the See also:lower See also:surface is clothed with a dense white down, which likewise covers the See also:young shoots—giving, with the bark, a hoary aspect to the whole tree. As in all poplars, the catkins expand in See also:early See also:spring, long before the leaves unfold; the ovaries bear four linear stigma lobes; the capsules ripen in May.

A nearly related form, which may be regarded as a sub-species, canescens, the See also:

grey poplar of the nurseryman, is distinguished from the true abele by its smaller, less deeply cut leaves, which are grey on the upper side, but not so hoary beneath as those of P. alba; the See also:pistil has eight stigma lobes. Both trees occasionally attain a height of 90 ft. or more, but rarely continue to form See also:sound timber beyond the first See also:half-See also:century of growth, though the trunk will sometimes endure for a See also:hundred and fifty years. The See also:wood is very white, and, from its soft and even See also:grain, is employed by turners and See also:toy-makers, while, being tough and little liable to split, it is also serviceable for the construction of packing cases, the lining of carts and waggons, and many similar purposes; when thoroughly seasoned it makes See also:good flooring planks, but shrinks much in drying, weighing about 58 lb per cubic See also:foot when green, but only 33i lb when dry. The white poplar is an ornamental tree, from its graceful though somewhat irregular growth and its dense hoary foliage; it has, however, the disadvantage of throwing up numerous suckers for some yards around the trunk. The grey and white poplars are usually multiplied by long cuttings; the growth is so rapid in a moist loamy See also:soil that, according to Loudon, cuttings 9 ft. in length, planted beside a stream, formed in twelve years trunks ro in. in See also:diameter. Both these allied forms occur throughout central and See also:southern See also:Europe, but, though now abundant in See also:England, it is doubtful whether they are there indigenous. P. alba suffers much from the ravages of wood-eating larvae, and also from fungoid growths, especially where the branches have been removed by pruning or See also:accident. P. See also:nigra, the See also:black poplar, is a tree of large growth, with dark, deeply-furrowed bark on the trunk, and ash-coloured branches; the smooth deltoid leaves, serrated regularly on the margin, are of the deep green tint which has given name to the tree; the petioles, slightly compressed, are only about half the length of the leaves. The black poplar is See also:common in central and southern Europe and in some of the adjacent parts of See also:Asia, but, though abundantly planted in See also:Britain, is not there indigenous. The wood is of a yellowish tint. In former days this was the prevalent poplar in Britain, and the timber was employed for the purposes to which that of other species is applied, but has been superseded by P. monilifera and its varieties; it probably furnished the poplar wood of the See also:Romans, which, from its lightness and soft tough grain, was in esteem for See also:shield-making; in See also:continental Europe it is still in some See also:request; the bark, in See also:Russia, is used for tanning See also:leather, while in See also:Kamchatka it is sometimes ground up and mixed with See also:meal; the See also:gum secreted by the buds was employed by the old herbalists for various medicinal purposes, but is probably nearly inert; the cotton-like down of the See also:seed has been converted into a See also:kind of See also:vegetable See also:felt, and has also been used in paper-making. A closely related form is the well-known See also:Lombardy poplar, P. fastigiata, remarkable for its tall, See also:cypress-like shape, caused by the nearly See also:vertical growth of the branches.

Probably a See also:

mere variety of the black poplar, its native See also:land appears to have been See also:Persia or some neighbouring See also:country; it was unknown in See also:Italy in the days of See also:Pliny, while from remote times it has been an inhabitant of See also:Kashmir, the See also:Punjab, and Persia, where it is often planted along roadsides for the purpose of shade; it was probably brought from these countries to southern Europe, and derives its popular name from its abundance along the See also:banks of the Po and other See also:rivers of Lombardy, where it is said now to spring up naturally from seed, like the indigenous black poplar. It was introduced into See also:France in 1749, and appears to have been grown in See also:Germany and Britain soon after the See also:middle of the last century, if not earlier. The Lombardy poplar is valuable chiefly as an ornamental tree, its timber being of very inferior quality; its tall, erect growth renders it useful to the landscape-gardener as a See also:relief to the rounded forms of other trees, or in contrast to the See also:horizontal lines of the See also:lake or river-See also:bank where it delights to grow. In Lombardy and France tall hedges are sometimes formed of this poplar for shelter or shade, while in the suburban parks of Britain it is serviceable as a See also:screen for hiding buildings or other unsightly See also:objects from view; its growth is extremely rapid, and it often attains a height of too ft. and upwards, while from 7o to 8o ft. is an See also:ordinary size in favourable situations. P. canadensis, the " cotton-wood " of the western prairies, and its varieties are perhaps the most useful trees of the genus, often forming almost the only arborescent vegetation on the See also:great See also:American plains. It is a tree of rather large growth, sometimes See also:Ioo ft. high, with rugged grey trunk 7 or 8 ft. in diameter, and with the shoots or young branches more or less angular; the glossy deltoid leaves are sharply pointed, somewhat cordate at the base, and with flattened petioles; the fertile catkins ripen about the middle of See also:June, when their opening capsules See also:discharge the cottony seeds which have given the tree its common western name; in New England it is sometimest called the " river poplar." The cotton-wood timber, though soft and perishable, is of value in its See also:prairie habitats, where it is frequently the only available wood either for See also:carpentry or See also:fuel; it has been planted to a considerable extent in some parts of Europe, but in England a form of this species known as P. monilifera is generally preferred from its larger and more rapid growth. In this well-known variety the young shoots are but slightly angled, and the branches in the second See also:year become round; the deltoid See also:short-pointed leaves are usually straight or even rounded at the base, but sometimes are slightly cordate; the capsules ripen in Britain about the middle of May. This tree is of extremely rapid growth, and has been known to attain a height of 70 ft. in sixteen years; it succeeds best in deep loamy soil, but will flourish in nearly any moist but well-drained situation. The timber is much used in some rural districts for flooring, and is durable for indoor purposes when protected from dry-rot; it has, like most poplar See also:woods, the See also:property of resisting See also:fire better than other timber. The native country of this form has been much disputed; but, though still known in many See also:British nurseries as the " black See also:Italian poplar," it is now well ascertained to be an indigenous tree in many parts of See also:Canada and the States, and is a mere variety of P. canadensis; it seems to have been first brought to England from Canada in 1772. In See also:America it seldom attains the large size it often acquires in England, and it is there of less rapid growth than the prevailing form of the western plains; the name of " cotton-wood " is locally given to other species. P. macrophylla or candicans, commonly known as the See also:Ontario poplar, is remarkable for its very large See also:heart-shaped leaves, some-times to in. long; it is found in New ngland and the milder parts of Canada, and is frequently planted in Britain; its growth is extremely rapid in moist land; the buds are covered with a balsamic secretion.

The true See also:

balsam poplar, or tacamahac, P. balsamifera, abundant in most parts of Canada and the northern States, is a tree of rather large growth, often of somewhat fastigiate See also:habit, with round shoots and oblong-ovate See also:sharp-pointed leaves, the base never cordate, the petioles round, and the disk deep glossy green above but somewhat downy below. This tree, the " liard " of the See also:Canadian voyageur, abounds on many of the river sides of the north-western plains; it occurs in the neighbourhood of the Great Slave Lake and along the See also:Mackenzie River, and forms much of the See also:drift-wood of the See also:Arctic See also:coast. In these northern habitats it attains a large size; the wood is very soft; the buds yield a gum-like balsam,from which the common name is derived; considered valuable as an antiscorbutic, this is said also to have diuretic properties; it was formerly imported into Europe in small quantities under the name of " See also:baume focot," being scraped off in the spring and put into shells. This balsam gives the tree a fragrant odour when the leaves are unfolding. The tree grows well in Britain, and acquires occasionally a considerable size. Its fragrant shoots and the See also:fine yellow green of the young leaves recommend it to the ornamental planter. It is said by See also:Aiton to have been introduced into Britain about the end of the 17th century. P. euphratica, believed to be the weeping See also:willow of the Scriptures, is a large tree remarkable for the variability in the shape of its leaves, which are linear in young trees and vigorous shoots, and broad and ovate on older branches. It is a native of North See also:Africa and Western and Central Asia, including North-See also:West See also:India. With the date See also:palm it is believed to have furnished the rafters for the buildings of See also:Nineveh.

End of Article: POPLAR (Lat. Populus)

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