a family of dicotyledonous plants. They are predominantly herbs and semishrubs. more rarely shrubs, and very rarely (in the tropics) small trees. The leaves are alternate, as a rule, and almost always with a sheathing growth (ocrea) at the base. The blossoms are small, regular, and for the most part monoecious, usually with compound inflorescences. The perianth is simple, three- or (rarely) two-membered. most often of three to six free or partly knitted green, white, or reddish leaflets. There are three to nine stamens, rarely more. The gynecium consists of three (more rarely two to four) carpels; the ovary is superior; the fruit is nutlike, often trihedral, with a remaining perianth. There are approximately 40 genera (900 species) growing over the entire globe but mainly in the temperate zone of the northern hemisphere. In the USSR there are eight to ten genera (almost 300 species). Those of greatest economic significance are buckwheat, rhubarb, dock, Calligonum, snakeweed, and Atraphaxis(there are approximately 20 species in the USSR).