[Populus.[Q] Nat. Ord.—AmentiferÆ; Linn.—Dioec. Octa.]

The Poplars are deciduous trees, mostly growing to a large size; natives of Europe, North America, some parts of Asia, and the north of Africa. They are all of rapid growth, some of them extremely so; and they are all remarkable for a tremulous motion in their leaves, when agitated by the least breath of wind. The species delight in a rich, moist soil, in the neighbourhood of running water, but they do not thrive in marshes or soils saturated with stagnant moisture. Their wood is light, of a white or pale yellowish colour, very durable when kept dry, not liable to warp or twist when sawn up, and yields, from its elasticity, without splitting or cracking when struck with violence; that of some species is also very slow in taking fire, and burns, when ignited, in a smouldering manner, without flame, on which account it is valuable, and extensively used for the flooring of manufactories and other buildings. Of the fifteen species of Poplar described in Loudon's Arboretum, three are believed to be natives of this country—P. canescens, P. tremula, and P. nigra.

P. canescens, the Gray or Common White Poplar, and its different varieties, form trees of from eighty to one hundred feet high and upwards, with silvery smooth bark, upright and compact branches, and a clear trunk, to a considerable height, and a spreading head, usually in full-grown trees, but thinly clothed with foliage. The leaves are roundish, deeply waved, lobed, and toothed; downy beneath, chiefly grayish; leaves of young shoots cordate-ovate, undivided fertile catkins cylindrical. Stigmas 8.

The White Poplar is commonly propagated by layers, which ought to be transplanted into nursery lines for at least one year before removal to their final situation. The tree is admirably adapted for thickening or filling up blanks in woods and plantations; and, for this purpose, truncheons may be planted from three to four inches in diameter, and from ten to twelve feet high. These truncheons have the great advantage of not being overshadowed by the adjoining trees, which is almost always the case when young plants are used for filling up vacancies among old trees. In a moderately good and moist soil, the White Poplar will attain in ten years, the height of thirty feet or upwards, with a trunk from six to nine inches in diameter.

As an ornamental tree, the White Poplar is not unworthy of a place in extensive parks and grounds, particularly when planted in lone situations, or near to water; it ought, however, to be grouped and massed with trees of equally rapid growth, else it soon becomes disproportionate, and out of keeping with those whose progress is comparatively slow. It is well adapted in our climate for a wayside tree, as it has no side branches to prevent the admission of light and free circulation of air; and also to form avenues, when an effect is wished to be produced in the shortest possible time.

The Aspen or Trembling Poplar, P. tremula, is inferior to few of its tribe, presenting the appearance of a tall, and, in proportion to its height, rather a slender tree, with a clean straight trunk; the head ample, and formed of horizontal growing branches, not crowded together, which assume, towards the extremities, a drooping or pendulous direction. The leaves are nearly orbicular, sinuate, or toothed, smooth on both sides; foot-stalks compressed; young branches hairy; stigmas 4, crested and eared at the base. The foliage is of a fine rich green; and the upper surface of the leaves being somewhat darker than the under, a sparkling and peculiar effect is produced by the almost constant tremulous motion with which they are affected by the slightest breath of air, and which is produced by the peculiar form of the foot-stalks, which in this species is flattened, or vertically compressed in relation to the plane of the leaf, causing a quivering or double lateral motion, instead of the usual waving motion, where the foot-stalk is round, or else compressed horizontally.

The Black Poplar, P. nigra, is a tree of the largest size, with an ample head, composed of numerous branches and terminal shoots. The bark is ash-coloured, and becomes rough and deeply furrowed with age. The catkins are bipartite, cylindrical; the barren appear in March or April, long before the expansion, of the leaves, and, being large and of a deep red colour, produce a rich effect at that early period of the year. The capsules or seed-vessels of the fertile catkin are round, and contain a pure white cottony down, in which the seeds are enveloped. The leaves appear about the middle of May, and, when they first expand, their colour is a mixture of red and yellow; afterwards they are of a pale light green, with yellowish foot-stalks; remarkably triangular, acuminate, serrate, smooth on both sides; stigmas 4.

There is a Black Poplar at Alloa House, in Clackmannanshire, which, in 1782, at the height of between three and four feet from the ground, measured thirteen feet and a half in circumference. There is also a very graceful and beautiful tree of the same species at Bury St. Edmunds, ninety feet in height, and which measures, at the distance of three feet from the ground, fifteen feet in girth. The trunk rises forty-five feet before it divides, when it throws out a vast profusion of branches.

The Poplar was dedicated by the Romans to Hercules, in honour of his having destroyed the monster Cacus in a cavern near to the Aventine Mount, where the Poplar formerly flourished in abundance. In Pitt's translation of Virgil, the following reference is made to the rite of crowning with the Poplar:—

From that blest hour th' Arcadian tribe bestowed
Those solemn honours on their guardian god.
Potitius first, his gratitude to prove,
Adored Alcides[2] in the shady grove;
And with the old Pinarian sacred line
These altars raised, and paid the rites divine,—
Rites, which our sons for ever shall maintain;
And ever sacred shall the grove remain.
Come, then, with us to great Alcides pray,
And crown your heads, and solemnize the day.
Invoke our common god with hymns divine,
And from the goblet pour the generous wine.
He said, and with the Poplar's sacred boughs,
Like great Alcides, binds his hoary brows.