''Polygonum erectum'', commonly called erect knotweed, is a North American species of herbaceous plant in the buckwheat family (

Polygonaceae The Polygonaceae are a family of flowering plants known informally as the knotweed family or smartweed—buckwheat family in the United States. The name is based on the genus '' Polygonum'', and was first used by Antoine Laurent de Jussieu in 1 ...

). It is found primarily in the northeastern and north-central parts of the United States, but with scattered populations in other parts of the US and also in Canada. Its natural habitat is in bottomland forests and riparian areas. It is tolerant of ecological degradation, and can also be found in disturbed open areas such as pastures and lawns. It was once cultivated for food by Native Americans as part of the group of crops known as the

Eastern Agricultural Complex The Eastern Agricultural Complex in the woodlands of eastern North America was one of about 10 independent centers of plant domestication in the pre-historic world. Incipient agriculture dates back to about 5300 BCE. By about 1800 BCE the Native ...

Description

''Polygonum erectum'' is an erect annual growing tall with many to few, non-wiry branches. The leaves have distinct veins and entire edges or have jagged cut edges. The

pedicel Pedicle or pedicel may refer to: Human anatomy *Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures ...

s are shorter or equal the length of the calyx and typically longer than the ocreae. The closed flowers have a calyx that is typically long, green in color and 5-lobed. Flowers in clusters of 1 to 5 in cymes that are produced in the axils of most leaves. The calyx segments are unequal with the outer lobes longer and not keeled and the inner ones narrowly keeled. The

tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s are greenish, with yellowish tinting or sometimes with whitish tints. The seeds are produced in

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

s called

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

s that can be of two different types; one type is dark brown with a shiny surface and is broadly egg-shaped, typically about long. The other achene type is dull brown, exsert and egg-shaped, and long. Late season fruiting is uncommon and if produced the achenes are long. File:Polygonum erectum BB-1913.png, Botanical illustration of ''Polygonum erectum''

Conservation

''Polygonum erectum'' is considered to be globally secure. However, it is uncommon throughout much of its range, and population have declined dramatically in some regions. It is listed as endangered in

New Hampshire New Hampshire is a U.S. state, state in the New England region of the northeastern United States. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Gulf of Maine to the east, and the Canadian province of Quebec t ...

and

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

References

{{Taxonbar, from=Q377934 erectum Flora of Canada Flora of the United States Crops originating from Pre-Columbian North America Plants used in Native American cuisine Plants described in 1753 Taxa named by Carl Linnaeus Pseudocereals