Polygonum polygaloidesMeisn.

milkwort knotweed

WFO wfo-0001101047 Accepted WFO 2026-06 5 photographs CC BY

Plate 1 figs. a–e · 3 observations

This species has been photographed under an open licence only 3 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 polygaloides, photographed by Ken-ichi Ueda
fig. a Ken-ichi Ueda, CC BY 4.0 / 2019-07-09 / obs. 45715593
Polygonum polygaloides, photographed by Adam J. Searcy
fig. b Adam J. Searcy, CC BY 4.0 / obs. 144824291
Polygonum polygaloides, photographed by Ken-ichi Ueda
fig. c Ken-ichi Ueda, CC BY 4.0 / obs. 45715439
Polygonum polygaloides, photographed by Ken-ichi Ueda
fig. d Ken-ichi Ueda, CC BY 4.0 / obs. 45715431
Polygonum polygaloides, photographed by Adam J. Searcy
fig. e Adam J. Searcy, CC BY 4.0 / obs. 144824299

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 14 botanical countries

Regions where Polygonum polygaloides is native: Alberta, Arizona, British Columbia, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Saskatchewan, Utah, Washington, Wyoming AlbertaArizonaBritish ColumbiaCaliforniaColoradoIdahoMontanaNevadaNew MexicoOregonSaskatchewanUtahWashingtonWyoming
Native distribution of Polygonum polygaloides, 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
Alberta ABT NORTHERN AMERICA
Arizona ARI
British Columbia BRC
California CAL
Colorado COL
Idaho IDA
Montana MNT
Nevada NEV
New Mexico NWM
Oregon ORE
Saskatchewan SAS
Utah UTA
Washington WAS
Wyoming WYO

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 9 synonyms

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 confertiflorum Nutt. ex Piper
  • Polygonum esotericum L.C.Wheeler
  • Polygonum kelloggii Greene
  • Polygonum kelloggii var. confertiflorum (Nutt. ex Piper) Dorn
  • Polygonum minutissimum L.O.Williams
  • Polygonum polygaloides subsp. polygaloides
  • Polygonum polygaloides var. montanum Brenckle
  • Polygonum unifolium Small
  • Polygonum watsonii Small

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.