The genus Fagopyrum is in the flowering plant family Polygonaceae. It includes some important food plants, such as F. esculentum (buckwheat) and F. tataricum. The genus is native to the Indian subcontinent, much of Indochina, and central and southeastern China. Species have been widely introduced elsewhere, throughout the Holarctic and parts of Africa and South America.

The Polygonaceae are a family of flowering plants known informally as the knotweed family or smartweed—buckwheat family in the United States. The name is based on the genus Polygonum, and was first used by Antoine Laurent de Jussieu in 1789 in his book, Genera Plantarum. The name may refer to the many swollen nodes the stems of some species have, being derived from Greek [poly meaning 'many' and gony meaning 'knee' or 'joint']. Alternatively, it may have a different origin, meaning 'many seeds'.