Polygonum paronychia
Encyclopedia
Polygonum paronychia is a species of flowering plant in the knotweed family
known by the common names dune knotweed, black knotweed, and beach knotweed. It is native to the coastline of western North America from British Columbia
to California
, where it grows in sandy coastal habitat such as beaches and scrub.
producing multibranched brown stems up to a meter long. The stems may root at nodes that come in contact with moist substrate. The leaves are alternately arranged on the stems but are mostly located bunched around the tips of the stem branches. The leaves are linear to lance-shaped with rolled edges and bristly midribs on the undersides. Each leaf has a large stipule
which forms a wide, membranous ochrea
. The ochrea is up to 2 centimeters long and is persistent, fraying into fibrous, silvery shreds that remain on the plant through the seasons. Flowers occur in the leaf axils. Each is up to a centimeter wide with five narrow white or pinkish corolla lobes.
Polygonaceae
Polygonaceae is a family of flowering plants known informally as the "knotweed family" or "smartweed family"— "buckwheat family" in the United States. The name is based on the genus Polygonum and was first used by Antoine Laurent de Jussieu in 1789 in his book, Genera Plantarum. The name refers...
known by the common names dune knotweed, black knotweed, and beach knotweed. It is native to the coastline of western North America from British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
to California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, where it grows in sandy coastal habitat such as beaches and scrub.
Description
It is a small prostrate or upright shrubShrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
producing multibranched brown stems up to a meter long. The stems may root at nodes that come in contact with moist substrate. The leaves are alternately arranged on the stems but are mostly located bunched around the tips of the stem branches. The leaves are linear to lance-shaped with rolled edges and bristly midribs on the undersides. Each leaf has a large stipule
Stipule
In botany, stipule is a term coined by Linnaeus which refers to outgrowths borne on either side of the base of a leafstalk...
which forms a wide, membranous ochrea
Ochrea
Ochrea, commonly spelled ocrea, is a structure formed of stipules fused into a sheath surrounding the stem. It is a diagnostic character in the Polygonaceae.In palms it denotes an extension of the leaf sheath beyond the petiole insertion....
. The ochrea is up to 2 centimeters long and is persistent, fraying into fibrous, silvery shreds that remain on the plant through the seasons. Flowers occur in the leaf axils. Each is up to a centimeter wide with five narrow white or pinkish corolla lobes.