Polygonum achoreumS.F.Blake

leathery knotweed

WFO wfo-0001101011 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 4 observations

This species has been photographed under an open licence only 4 times, so some figures below are different views of the same plant, taken on the same day, rather than different individuals. They are usually different parts of it: the leaf, the flower, the bark.

Polygonum achoreum, photographed by Alison Northup
fig. a Alison Northup, CC BY 4.0 / 2019-07-09 / obs. 45661295
Polygonum achoreum, photographed by Ryan Hodnett
fig. b Ryan Hodnett, CC BY-SA 4.0 / obs. 7859339
Polygonum achoreum, photographed by Matt Lavin
fig. c Matt Lavin, CC BY 4.0 / obs. 178387602
Polygonum achoreum, photographed by Alison Northup
fig. d Alison Northup, CC BY 4.0 / obs. 45661331
Polygonum achoreum, photographed by Ryan Hodnett
fig. e Ryan Hodnett, CC BY-SA 4.0 / obs. 7859340
Polygonum achoreum, photographed by Matt Lavin
fig. f Matt Lavin, CC BY 4.0 / obs. 178387609
Polygonum achoreum, photographed by W. Terry Hunefeld
fig. g W. Terry Hunefeld, CC BY 4.0 / obs. 9923401
Polygonum achoreum, photographed by W. Terry Hunefeld
fig. h W. Terry Hunefeld, CC BY 4.0 / obs. 9923503

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 36 botanical countries

Regions where Polygonum achoreum is native: Alaska, Alberta, British Columbia, Colorado, Connecticut, Idaho, Illinois, Indiana, Iowa, Kansas, Maine, Manitoba, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New Brunswick, New York, North Dakota, Northwest Territories, Nova Scotia, Ohio, Ontario, Oregon, Québec, Saskatchewan, South Dakota, Utah, Vermont, Washington, West Virginia, Wisconsin, Wyoming, Yukon AlaskaAlbertaBritish ColumbiaColoradoConnecticutIdahoIllinoisIndianaIowaKansasMaineManitobaMichiganMinnesotaMissouriMontanaNebraskaNevadaNew BrunswickNew YorkNorth DakotaNorthwest TerritoriesNova ScotiaOhioOntarioOregonQuébecSaskatchewanSouth DakotaUtahVermontWashingtonWest VirginiaWisconsinWyomingYukon
Native distribution of Polygonum achoreum, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows.
RegionTDWG codeContinent
Alaska ASK NORTHERN AMERICA
Alberta ABT
British Columbia BRC
Colorado COL
Connecticut CNT
Idaho IDA
Illinois ILL
Indiana INI
Iowa IOW
Kansas KAN
Maine MAI
Manitoba MAN
Michigan MIC
Minnesota MIN
Missouri MSO
Montana MNT
Nebraska NEB
Nevada NEV
New Brunswick NBR
New York NWY
North Dakota NDA
Northwest Territories NWT
Nova Scotia NSC
Ohio OHI
Ontario ONT
Oregon ORE
Québec QUE
Saskatchewan SAS
South Dakota SDA
Utah UTA
Vermont VER
Washington WAS
West Virginia WVA
Wisconsin WIS
Wyoming WYO
Yukon YUK

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Also published as 1 synonym

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Polygonum erectum subsp. achoreum (S.F.Blake) Á.Löve & D.Löve

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.