polygonum

Polygonum is a genus of about 130 species of flowering plant in the buckwheat and knotweed family Polygonaceae. Common names include knotweed and knotgrass (though the common names may refer more broadly to plants from Polygonaceae). In the Middle English glossary of herbs Alphita (c. 1400–1425), it was known as ars-smerte. There have been various opinions about how broadly the genus should be defined. For example, buckwheat (Fagopyrum esculentum) has sometimes been included in the genus as Polygonum ...