| Polygonum parryi | |
|---|---|
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Core eudicots |
| Order: | Caryophyllales |
| Family: | Polygonaceae |
| Genus: | Polygonum |
| Species: | P. parryi |
| Binomial name | |
| Polygonum parryi Greene |
|
Polygonum parryi is a species of flowering plant in the knotweed family known by the common name Parry's knotweed. It is native to the western United States from Washington to California, where it grows in several types of moist, open habitat in mountainous and coastal areas.
It is a small annual herb forming mats or cushions of short, angled stems growing erect to 7 or 8 centimeters in maximum height. The greenish brown stems are lined densely and evenly with linear, spine-tipped leaves. The lowest leaves are longest, reaching up to 2 centimeters long, while leaves near the branch tips are small and scale-like. Each leaf has a thin, wide stipule which forms a fringed, fibrous ochrea around the base of the leaf. White flowers less than 2 millimeters wide occur in the leaf axils.