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 seedvessels 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 These altars raised, and paid the rites divine,- *The Greek name of Hercules. [Pinus sylvestris. Nat. Ord.-Coniferæ; Linn.-Monoc. Mon.] THE Scotch Fir or Pine, and its varieties, are indigenous throughout the greater part of Europe. It also extends into the north, east, and west of Asia; and is found at Nootka Sound in Vancouver's Island, on the north-west coast of North America. Generic characters. Flowers monoecious. Cones woody, with numerous 2-seeded scales, thickened and angular at the end. Seeds with a crustaceous coat, winged. Leaves acerose, in clusters of from 2 to 5, surrounded by scarious scales at the base. In the south of Europe it grows at an elevation of from 1000 to 1500 feet; in the Highlands of Scotland, at 2700 feet; and in Norway and Lapland, at 700 feet. Widely dispersed, however, as the species is throughout the mountainous regions of Europe, it is only found in profusion between 52° and 65° N. lat. It occurs in immense forests in Poland and Russia, as well as in northern Germany, Sweden, Norway, and Lapland, up to the 70° of N. lat. The indigenous forests of Scotland, which formerly occupied so large a portion of its surface, have been greatly reduced within the last sixty years, chiefly on account of the pecuniary embarrassments of their proprietors. The The Scotch Fir, in favourable situations, attains the height of from eighty to one hundred feet, with a trunk from two to four feet in diameter, and a head somewhat conical or rounded, but generally narrow in proportion to its height, as compared with the heads of other broad-leafed trees. bark is of a reddish tinge, comparatively smooth, scaling off in some varieties, and rough and furrowed in others. The branches are disposed in whorls from two to four together, and sometimes five or six; they are at first slightly turned upwards, but finally become somewhat pendant, with the exception of those branches which form the summit of the tree. The leaves are in sheaths, spirally disposed on the branches; they are distinguished at first sight from all other pines in which the leaves are in pairs, by being much more glaucous, more especially when in a young state, and |