Polygonum biconvexum

Plate 1 figs. a–h · 8 separate observations

Polygonum biconvexum, photographed by fagushayata — fig. d fagushayata, CC BY-SA 4.0 / obs. 165754853

Polygonum biconvexum, photographed by 葉子 — fig. e 葉子, CC0 1.0 / obs. 48162864

Polygonum biconvexum, photographed by Cheng-Tao Lin — fig. f Cheng-Tao Lin, CC BY 4.0 / obs. 34182630

Polygonum biconvexum, photographed by koala0090 — fig. h koala0090, CC BY 4.0 / obs. 12386245

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 2 botanical countries

Native distribution of Polygonum biconvexum, 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.

Region	TDWG code	Continent
Taiwan	TAI	ASIA-TEMPERATE
Sumatera	SUM	ASIA-TROPICAL

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 47 in flower of 52 examined

80%

100%

82%

100%

Proportion of examined Polygonum biconvexum in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	1	1	too few examined
Feb	2	2	too few examined
Mar	4	5	80%	38% to 96%
Apr	0	1	too few examined
May	2	2	too few examined
Jun	1	1	too few examined
Jul	5	5	100%	57% to 100%
Aug	9	11	82%	52% to 95%
Sep	2	2	too few examined
Oct	11	11	100%	74% to 100%
Nov	8	8	100%	68% to 100%
Dec	2	3	too few examined

Peak flowering in Jul. Each bar is the share of Polygonum biconvexum 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. 47 of 52 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 7 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 4 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 biconvexa (Hayata) Nemoto
Polygonum hastatotrilobum var. lenticulare Danser
Polygonum thunbergii f. bicovexum (Hayata) Liu et al.
Truellum biconvexum (Hayata) Soják

Sourcesevery claim on this page

World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
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.