Polygonum posumbuBuch.-Ham. ex D.Don

Oriental lady's thumb

WFO wfo-0001101609 Accepted WFO 2026-06 8 photographs CC0 / CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Polygonum posumbu, photographed by 國立臺灣博物館
fig. a 國立臺灣博物館, CC BY 4.0 / 2020-03-07 / obs. 62987573
Polygonum posumbu, photographed by 葉子
fig. b 葉子, CC0 1.0 / obs. 48155665
Polygonum posumbu, photographed by fagushayata
fig. c fagushayata, CC BY-SA 4.0 / obs. 32366197
Polygonum posumbu, photographed by harum.koh
fig. d harum.koh, CC BY-SA 4.0 / obs. 5219394
Polygonum posumbu, photographed by 呂一起(Lyu yi-chi)
fig. e 呂一起(Lyu yi-chi), CC BY 4.0 / obs. 63091981
Polygonum posumbu, photographed by fagushayata
fig. f fagushayata, CC BY-SA 4.0 / obs. 28834031
Polygonum posumbu, photographed by 古淑玲
fig. g 古淑玲, CC0 1.0 / obs. 158551071
Polygonum posumbu, photographed by WATANABE Hitoshi 渡辺仁
fig. h WATANABE Hitoshi 渡辺仁, CC BY 4.0 / obs. 101880360

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 23 botanical countries

Regions where Polygonum posumbu is native: China North-Central, China South-Central, China Southeast, Hainan, Japan, Korea, Kuril Is., Manchuria, Primorye, Taiwan, Tibet, Assam, Bangladesh, East Himalaya, Laos, Malaya, Myanmar, Nepal, Nicobar Is., Philippines, Thailand, Vietnam, West Himalaya China North-CentralChina South-CentralChina SoutheastHainanJapanManchuriaPrimoryeTaiwanTibetAssamBangladeshEast HimalayaLaosMalayaMyanmarNepalPhilippinesThailandVietnamWest Himalaya KoreaNicobar Is.
Native distribution of Polygonum posumbu, 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. Regions too small to draw at this scale are marked with a dot.
RegionTDWG codeContinent
Assam ASS ASIA-TROPICAL
Bangladesh BAN
East Himalaya EHM
Laos LAO
Malaya MLY
Myanmar MYA
Nepal NEP
Nicobar Is. NCB
Philippines PHI
Thailand THA
Vietnam VIE
West Himalaya WHM
China North-Central CHN ASIA-TEMPERATE
China South-Central CHC
China Southeast CHS
Hainan CHH
Japan JAP
Korea KOR
Kuril Is. KUR
Manchuria CHM
Primorye PRM
Taiwan TAI
Tibet CHT

Not drawn on the map: Kuril Is.. We hold no public-domain boundary for this region, so it is listed rather than guessed at.

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.

Flowering 48 in flower of 64 examined

Peak flowering in May. Each bar is the share of Polygonum posumbu observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 48 of 64 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 6 months have fewer than 5 examined observations, so no proportion is drawn for them. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Also published as 7 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.

  • Persicaria posumbu (Buch.-Ham. ex D.Don) H.Gross
  • Persicaria yokusaiana (Makino) Nakai
  • Polygonum caespitosum subsp. yokusaianum (Makino) Danser
  • Polygonum cespitosum Blume
  • Polygonum procumbens Y.L.Chang & S.X.Li
  • Polygonum pronum C.F.Fang
  • Polygonum yokusaianum Makino

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. USDA PLANTS Database. common name, checklist symbol POCE4. public domain. 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.