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Polygonum amphibium var. emersum
Polygonum amphibium L. var. emersum Michx.
Longroot Smartweed
Polygonaceae (Buckwheat Family)
Synonym(s): Persicaria amphibia, Persicaria amphibia var. emersa, Persicaria coccinea, Persicaria muehlenbergii, Polygonum amphibium var. coccineum, Polygonum coccineum, Polygonum coccineum var. pratincola, Polygonum coccineum var. terrestre, Polygonum muehlenbergii, Polygonum muehlenbergii var. terrestre
USDA Symbol: POAME
USDA Native Status: L48 (N), CAN (N)
Polygonum amphibium var. emersum has lanceolate leaves with narrowly tapering tips and slender flower clusters at least 1 1/2 inches (4 cm) long. Once called P. coccineum, a separate species, this variety of Polygonum amphibium is aggressive to the point of being classified as a noxious weed.
Plant Characteristics
Duration: PerennialHabit: Herb
Fruit Type: Achene
Size Notes: Stems prostrate to ascending to erect, up to about 4 feet long in terrestrial plants, up to about 10 feet in some aquatic plants.
Bloom Information
Bloom Color: Red , PinkBloom Time: Jun , Jul , Aug , Sep
Distribution
USA: AR , AZ , CA , CO , CT , DC , DE , IA , ID , IL , IN , KS , KY , LA , MA , MD , ME , MI , MN , MO , MS , MT , NC , ND , NE , NH , NJ , NM , NV , NY , OH , OK , OR , PA , RI , SC , SD , TN , TX , UT , VA , VT , WA , WI , WV , WYCanada: AB , BC , MB , NB , NS , NT , PE , QC , SK
Growing Conditions
Aquatic: yesNational Wetland Indicator Status
Region: | AGCP | AK | AW | CB | EMP | GP | HI | MW | NCNE | WMVE |
Status: | OBL | OBL | OBL | OBL | OBL | OBL | OBL | OBL |
Web Reference
Webref 38 - Flora of North America (2019) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.Webref 23 - Southwest Environmental Information Network (2009) SEINet - Arizona Chapter
Additional resources
USDA: Find Polygonum amphibium var. emersum in USDA PlantsFNA: Find Polygonum amphibium var. emersum in the Flora of North America (if available)
Google: Search Google for Polygonum amphibium var. emersum
Metadata
Record Modified: 2023-05-02Research By: TWC Staff