263. The ASPEN, or TREMBLING POPLAR (Populus tremula), is a tree which grows in moist woods; has nearly circular leaves, toothed and angular at the edges, smooth on both sides, and attached to footstalks so long and slender as to be shaken by the slightest wind.
There is scarcely any situation in which the aspen will not flourish, but it succeeds best where the soil is moist and gravelly. Its wood is light, porous, soft, and of white colour; and, though inferior in excellence to that of the white poplar, is applicable to many useful purposes, particularly for field-gates, the frames of pack-saddles, for milk-pails, clogs, and the wood-work of patterns. It is improper for bedsteads, as it is liable to be infested by bugs. In some countries the bark of the young trees is made into torches.
264. The BLACK POPLAR (Populus nigra, Fig. 75) is a native tree of this country, known by its somewhat trowel-shaped leaves, which taper to a point, and are serrated, and smooth on both sides.
This tree grows rapidly, and attains a considerable size. Its wood is soft and light, and in some respects useful to engravers; and is occasionally sawed into boards, though these are not in general much esteemed. The bark is so thick and light that it is not unfrequently used by fishermen as buoys or floats to support their nets. The inhabitants of Kamtschatka dry and pulverise the inner rind of the black poplar-tree, and use it as an ingredient in bread. The buds, when they first appear, are covered with and contain a viscous and fragrant juice, which may be advantageously used in plasters.
265. The LOMBARDY or ITALIAN POPLAR (Populus dilatata) grows wild in Lombardy and the northern parts of Italy, and is distinguished by its somewhat trowel-shaped and serrated leaves, being smooth on both sides, and wider than they are long.
From its slender and perpendicular growth the Lombardy poplar is found useful for hop-poles, and may be formed into masts for small vessels. The wood, which is soft and free from knots, is employed by joiners, carpenters, and cartwrights. It is recommended as peculiarly valuable for the floors of granaries, some persons believing it so obnoxious to insects that weevils will not continue in such granaries. It may be wrought into very flexible shafts for carriages, or felloes for wheels; and, not being liable to split, is peculiarly adapted for packing cases.
The growth of this tree is so rapid, and the space of ground which it occupies is so small, that it is in almost universal request as an ornamental tree, in places that are not sufficiently spacious to admit of trees of more spreading form.
POLYANDRIA.
266. SAGO is a granulated preparation from the pith of a species of palm-tree (Cycas circinalis) which grows in India and Africa.
This tree attains the height of thirty or forty feet; has a straight and somewhat slender stem, and winged leaves at the summit, each seven or eight feet long, with the leaflets long and narrow.