The common Black or Sweet birch. (B. lenta.) This is the sort most generally known by the name of the birch, and is widely diffused over the middle and southern states. In color and appearance the bark much resembles that of the cherry tree; on old trees, at the close of winter, it is frequently detached in transverse portions, in the form of hard ligneous plates six or eight inches broad. The leaves, for a fortnight after their appearance, are covered with a thick silvery down, which disappears soon after. They are about two inches long, serrate, heart-shaped at the base, acuminate at the summit, and of a pleasing tint and fine texture. The wood is of excellent quality, and Michaux recommends its introduction largely into the forests of the north of Europe.