Buckwheat (Fagopyrum esculentum), also known as common buckwheat, Japanese buckwheat and silverhull buckwheat, is a plant cultivated for its grain-like seeds and as a cover crop.
A related and more bitter species, Fagopyrum tataricum, a domesticated food plant common in Asia, but not as common in Europe or North America is also referred to as buckwheat.
Despite the name, buckwheat is not related to wheat, as it is not a grass. Instead, buckwheat is related to sorrel, knotweed, and rhubarb. Because its seeds are eaten and rich in complex carbohydrates, it is referred to as a pseudocereal. The cultivation of buckwheat grain declined sharply in the 20th century with the adoption of nitrogen fertilizer that increased the productivity of other staples.
Common buckwheat was domesticated and first cultivated in inland Southeast Asia, possibly around 6000 BCE, and from there spread to Central Asia and Tibet, and then to the Middle East and Europe.