The common birch is planted as an ornamental tree in many countries. Both species of birch are native to northern and central Europe and northern Asia. The drug, birch leaves, comes from China, Poland, Russia, and other Eastern European countries.
The leaves of one of the two birch species are used for the drug. These are usually collected in the spring. Other parts that can be used are the bark (Betulae cortex), the leaf buds (Betulae gemmae), and the birch bark tar oil (Betulae pix).
Birch: typical characteristics
The hanging birch is an upright deciduous tree up to 30 meters tall with white, papery bark that, unlike the downy birch, turns dark with time. The tree bears drooping branches and triangular to diamond-shaped, relatively small leaves. The two birch species are closely related and often interbreed. The flowers hang down in long, yellowish formations.
The leaves of the weeping birch range from two to four centimeters wide and about three to seven centimeters long, triangular in shape. The edges of the leaves are sharply double serrated and hairless.
The leaves of the downy birch are somewhat smaller (about two to four centimeters wide and two and a half to five centimeters long) and ovate to triangular. They are coarsely toothed, softly hairy on both sides, and bear only a few glands.
On the underside there are small yellow hair tufts and light leaf veins. The two sides of the leaves differ in coloration: above they are rather dark green, the underside is lighter. Fine, three-lobed fruit scales and winged fruits are often found between the leaves.
Smell and taste of birch
The leaves of birch exude a slightly aromatic odor. In terms of taste, birch leaves are slightly bitter.
