Polygonum is a
genus in the
Polygonaceae family. Common names include
knotweed,
knotgrass,
bistort,
tearthumb,
mile-a-minute,
smartweed and several others. In the
Middle English glossary of
herbs Alphita ( 1400-1425), it was known as
ars-smerte. There have been various opinions about how broadly the genus should be defined. For example,
Buckwheat has sometimes been included in the genus.