''Polygonum polygaloides'' is a North American species of flowering plants in the

buckwheat family 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 1789 ...

known by the common names milkwort knotweed and polygala knotweed. It is native to much of western North America, where it can be found in many types of moist habitat. It is a variable species, usually divided into a number of subspecies.

Description

''Polygonum polygaloides'' is an annual herb producing slender, wiry green stems 1 to 30 centimeters (0.4–12 inches) in length. The linear or lance-shaped leaves are alternately arranged uniformly along the stem, the ones near the tips of stem branches highly reduced. The leaves have membranous

stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many speci ...

s which fuse to form silvery

ochrea An ochrea (Latin ''ocrea'', greave or protective legging), also spelled ocrea, is a plant structure formed of stipules fused into a sheath surrounding the stem, and is typically found in the Polygonaceae The Polygonaceae are a family of flower ...

at the leaf bases. The flowers are mainly located in clusters around the stem tips. They are white, pink, or red, and most remain closed.Flora of North America, ''Polygonum polygaloides'' Meisner 1856. Polygala knotweed
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Subspecies

Some sources accept the following as subspecies of ''Polygonum polygaloides'', while others regard all but subsp. ''polygaloides'' as belonging to a distinct species, ''P. kelloggii.''The Plant List, ''Polygonum polygaloides'' Meisn.
/ref>Biota of North America Program 2014 county distribution map, ''Polygonum polygaloides''
/ref> * ''Polygonum polygaloides'' subsp. ''confertiflorum'' (Nutt. ex Piper) J.C.Hickman – from

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

east to Saskatchewan and south as far as

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

* ''Polygonum polygaloides'' subsp. ''esotericum'' (L.C. Wheeler) J.C. Hickman –

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

* ''Polygonum polygaloides'' subsp. ''kelloggii'' (Greene) J.C.Hickman – from

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

* ''Polygonum polygaloides'' subsp. ''polygaloides'' –

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

References

External links

Jepson Manual Treatment, University of California – ''Polygonum polygaloides''''Polygonum polygaloides'' – Calphotos Photo gallery, University of California
polygaloides Flora of North America Plants described in 1856 {{Polygonaceae-stub