Poplar, or Populus, L. a genus of trees comprising 13 species, of which the following are the principal, and the three first are natives of Britain :

1. The alba. White Poplar, or Abele-Tree, grows in hedges and brooks, where it flowers in the month of March.—It delights in gravelly soils and lofty situations, though it also thrives in clay-lands.—This tree is remarkable for its speedy growth ; as it attains its full size in 20 years ; being, however, subject to excrescences resembling warts, that sometimes become exceedingly large; and, as they absorb humidity, occasion the tree to decay. Its wood is white, soft, though tough, and neither exposed to the ravages of worms, nor subject to warp or shrink : hence it is advantageously employed for wainscotting and floors ; as well as for packing-boxes, laths, and turnery-wares.— The bark of the white poplar, according to the Rev. Mr. Stone {Phil. Transec, vol.53), is eminently serviceable in curing agues. He gathered it in the summer, while abounding with sap ; and, after drying it in a gentle heat, he administered one dram, in powder, every fourth hour, between the paroxysms. In some instances, he was induced to combine it with the Peruvian bark; but, in general, the former alone proved singularly efficacious. — The dried leaves in the winter afford excellent provender for sheep.

2. The tremula, Trembling Poplar, Asp, or Aspen-tree, flourishes best, in moist woods and boggy grounds, though it will thrive in all other soils, excepting clays : it is in flower, during the months of March and April. This species impoverishes the land : its leaves destroy the grass, and the numerous shoots that spring from. the roots, spread so near to the surface of the ground, as to prevent the vegetation of every other plant. The leaves are eaten by sheep and goats, but refused by horses and hogs :—the bark, when young, is made into torches. The wood is extremely light, smooth, white, soft, and durable in the air ; and though inferior in point of excellence to that of the preceding species, it is usefully employed for pannels or pack-saddles, milk-pails, clogs, pattens, etc.—From the .straight stems of this tree, the most durable shingles are obtained; and Du Roy observes, that bricks burnt with such wood, in a green state, acquire a blueish glazing, and additional firmness. Nor is it less excellent for water-pipes; for which purpose it should be felled from April to June, immediately bored, and laid under-ground. It is, however, remarkable, that the wood of the trembling poplar is very liable to be infested with bugs; and consequently improper for bedsteads.

3. The nigra, or Black Poplar, grows very rapidly near rivers, and in shady, moist situations: it flowers in the month of March. the wood of this species is soft, light, and not apt to sprinter. Its bark is uncommonly light, resembling cork, and is therefore employed by fishermen to support their nets: the inner-rind is used by the inhabitants of Kamschatka as an ingredient in their bread.— The-buds, which appear early in the -spring, contain an unctuous, yellow, fragrant juice, which is the basis of Bee-glue (Propolis), and is employed only in ointments for plasters; though its medicinal properties recommend it for internal use :- if formed into a tincture, by means of rectified spirit, and then inspissated, the buds yield an odorous resin, that is reputed to be equal to many of the expensive resinous drugs imported from foreign countries. — The leaves afford a good winter fodder for cattle, and should be collected in October, before the branches are cut for faggots.—Lastly, the roots of the black poplar dissolve into a kind of jelly. - The wood is useful for the engraver; and,when sawed into boards, and sap-dried, is uncommonly durable.—Dioscorides asserts, that the bark of this tree, when chopped small, sown in richly-manured ground, and well watered, will produce an abundant crop of eatable mushrooms : yeast diluted with warm water, and poured on a stump of the black poplar, will be attended with a similar effect; but these fungous plants ought to be gathered after the first autumnal rains.

4. The fastigata, Po-Poplar, Italian, or Lombardy-Poplar, is a native of the northern parts of Italy: it also flourishes in moist situations; but will not succeed if its roots are too long covered with water.— On account of its rapid growth, this species is greatly esteemed for Ornamental plantations: its cuttings are useful for hop-poles : the wood being soft, free from knots, and easily worked, it is much employed by joiners, carpenters, and cartwrights; it may be wrought into very flexible shafts for carriages, or fellies for wheels. Farther, it forms excellent masts of small vessels, and is particularly serviceable for packing-boxes ; because the plank, yielding to the nail, is not liable to be split; and, in case the box, etc. be accidentally dropped- on the ground, the boards are not so easily broken or splintered, as those of oak and other trees. Lastly, it appears from numerous experiments made by Dambourney, that the Italian Poplar affords a dye of as delicate a lustre, and equally durable, as the finest yellow wood : its tinging matter is more readily extracted ; but, instead of striking a proper green with indigo, it changes to ah olive shade. The dry branches are preferable to those in a green state; nor should they be cut or bruised ; being possessed of the property of fixing the colours obtained from Brazil and logwood.

5. The balsamifera, or Carolina Poplar, is a native of Carolina, where it attains a considerable size. It is best adapted to boggy soils ; and, as it grows with •greater rapidity than any of the other species, it soon repays the expence of planting. Its wood is very soft, spongy, light, and principally employed for packing-boxes, though it also furnishes good posts for fences.—Dambourney obtained from the Carolina, as well as the other poplars, a fine fawn, nut, and similar grave colours for wool, according to the quantity of wood employed, and the length of time it was boiled.—The balsamic juic expressed from the flower-buds, is probably the American Tacama-haca, an excellent application to recent wounds, provided no nerves or news have been injured.

All the Poplars may be propagated either by layers, cuttings, or suckers, which should be planted in a nursery for two or three years previously to their removal. The most proper time for transplanting suckers is in October, when their leaves begin to decay; but, it the trees are to be reared from cuttings or layers, it will be advisable to set them in February, when they ought to be put about a foot and a half deep in the ground, and closely rammed in. These will speedily take root; and, if the soil be moist, will in a few years attain a considerable size.

To conclude this interesting article, we shall briefly state an important fact which deserves the attention of those who are in possession of numerous poplars. The different species of these trees produce, on the upper part of their seed-vessels, a woolly or downy substance, which is of considerable value : by combining it with cotton, Prof. Herzer, of Munich, has lately converted this composition into wadding, counterpanes, gloves, stockings, etc.—From a mixture of two ounces of the down before mentioned, and four ounces of hare's wool, he obtained excellent hats; and, according to his calculation, each poplar-tree yields not less than 401b. of such material.