in taxon plant used for medicine knotweed family prostrate knotweed plant PLANTS:POAV Polygonum aviculare or common knotgrass is a plant related to buckwheat and dock. It is also called prostrate knotweed, birdweed, pigweed and lowgrass. In Vietnam, it is widely used to prepare soup and hot pot, particularly in the southern region. [https://en.wikipedia.org/wiki/Polygonum_aviculare] birdweed lowgrass pigweed polygonum aviculare Polygonum aviculare requires discussion