Polygonum tenue

Michx.

Slender Knotweed

G5Secure Found in 4 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.132096
Element CodePDPGN0L2B0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderPolygonales
FamilyPolygonaceae
GenusPolygonum
Synonyms
Duravia sp. 2
Other Common Names
Pleatleaf Knotweed (EN) pleatleaf knotweed (EN) Renouée ténue (FR)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-06-11
Change Date1984-06-25
Edition Date2025-06-11
Edition AuthorsN. Ventrella (2025)
Threat ImpactUnknown
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Polygonum tenue is an annual forb occurring in exposed sites in dry acidic soils of eastern North America, from Ontario, Canada and Minnesota, Wyoming, and Maine south to Georgia and Texas in the United States. There are over 300 estimated occurrences of this taxon, which are potentially threatened by development, recreation, rights-of-way maintenance, invasive species, succession, and other threats in some places. Little is known about threats and trends, but with a large range extent, high number of occurrences, abundant habitat, broad habitat preferences, and no obvious intrinsic vulnerabilities, Polygonum tenue is considered secure.
Range Extent Comments
Polygonum tenue occurs in eastern North America, from Ontario, Canada, and Minnesota, Wyoming, and Maine south to Georgia and Texas in the United States (FNA 2005). Range extent was estimated to be over 3.3 million square kilometers using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 1994 and 2025 (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1994 and 2025, it is estimated that there are more than 300 occurrences rangewide (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).
Threat Impact Comments
Although threats are not widely documented, Polygonum tenue is potentially threatened by development, recreation, rights-of-way maintenance, invasive species, succession, and other threats in some places (NatureServe 2025). However, their overall impact is likely negligible given the species' broad range, large number of occurrences, tolerance of light disturbance, and affinity for typically abundant habitats, as well as no obvious intrinsic vulnerabilities.
Ecology & Habitat

Habitat

Polygonum tenue occurs on "dry acid soils in exposed sites" from 100-1000 m in elevation (FNA 2005). In the southeastern United States, it is found in "glades, barrens, and thin, rocky soils, over various rock types (including granite, diabase, amphibolite, greenstone, metagabbro, and shale), [and] also in dry sands" (Weakley and the Southeastern Flora Team 2025).
Terrestrial Habitats
Forest/WoodlandBarrens
Other Nations (2)
United StatesN5
ProvinceRankNative
IndianaSNRYes
MassachusettsS2Yes
New JerseyS3Yes
NebraskaSNRYes
OklahomaSNRYes
WyomingSNRYes
South DakotaSNRYes
IowaS4Yes
Rhode IslandSNRYes
MaineSHYes
MissouriSNRYes
TennesseeSNRYes
PennsylvaniaS5Yes
KansasS3Yes
GeorgiaSNRYes
District of ColumbiaSNRYes
VermontS1Yes
MichiganSNRYes
MarylandSNRYes
OhioSNRYes
ConnecticutSNRYes
WisconsinSNRYes
IllinoisS3Yes
AlabamaSNRYes
North CarolinaS2Yes
VirginiaS4Yes
New HampshireS1Yes
KentuckyS3Yes
DelawareSHYes
ArkansasSNRYes
South CarolinaSHYes
MinnesotaSNRYes
West VirginiaS4Yes
New YorkS3Yes
TexasSNRYes
CanadaN2
ProvinceRankNative
OntarioS2Yes
Threat Assessments

Plant Characteristics
DurationANNUAL
Economic Value (Genus)No
Roadless Areas (4)
Virginia (4)
AreaForestAcres
Beards MountainGeorge Washington National Forest7,505
JerkemtightGeorge Washington National Forest16,687
Mill MountainGeorge Washington National Forest10,840
Price MountainJefferson National Forest9,119
References (8)
  1. Flora of North America Editorial Committee (FNA). 2005. Flora of North America north of Mexico. Vol. 5. Magnoliophyta: Caryophyllidae: Caryophyllales, Polygonales, and Plumbaginales. Oxford Univ. Press, New York. vii + 656 pp.
  2. Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
  3. iNaturalist. 2025. Online. Available: https://www.inaturalist.org (accessed 2025).
  4. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  5. NatureServe. 2025. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  6. <p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>
  7. Southwest Environmental Information Network (SEINet). 2025. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2025).
  8. Weakley, A.S., and Southeastern Flora Team. 2025. Flora of the southeastern United States Web App. Edition of February 18, 2025. University of North Carolina Herbarium (NCU), North Carolina Botanical Garden, University of North Carolina, Chapel Hill. Online. Available: https://fsus.ncbg.unc.edu (accessed 2025).