Alder (alnus), a genus of plants belonging to the natural order betulaceœ. It has four stamens, and its fruit is without wings, by which characteristics it is distinguished from the birch, with which it was classed by the earlier botanists. The principal species are found in North America, though some of its varieties are met with on the eastern continent. The common alder (A. glutinosa) grows in moist localities, especially on the higher portions of swampy grounds, which are free from standing water. This tree is applied to many valuable purposes of practical utility. Its wood is prized by machinists as adapted to mill wheels and other work which is mostly under water. It is also in request for certain branches of cabinet-making and turnery. The charcoal made from its wood is of an excellent quality, and is highly esteemed for the manufacture of gunpowder The berk, which contains an astringent juice, is used for tanning, and, with the addition of copperas and other ingredients, forms a dye for several colors. The alder is also an ornamental tree, with its abundant foliage of deep green.
The Turkey alder (A.
Alder - Catkins and Seed.
incana) is abundant in the north of Europe, and is found to the east, even beyond the Can-casus. It is a taller and more erect tree than the common alder, and possesses many of the same properties, although it grows well in situations that are comparatively free from moisture. A beautiful species, A. cordifolia, or heart-leaved alder, is a native of Italy. The alder is easily cultivated, and, although not rapid in growth, can be obtained from seed with a great degree of certainty.