Cynanchum rostellatum(Turcz.) Liede & Khanum

rough potato

WFO wfo-0001424189 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Cynanchum rostellatum, photographed by Zinogre
fig. a Zinogre, CC BY-SA 4.0 / 2021-09-29 / obs. 160435628

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.

The specimen a real sheet, in a real collection

Herbarium
Royal Botanic Gardens, Kew
Accession
K005670993
Filed as
Cynanchum rostellatum (Turcz.) Liede & Khanum
Det. by
not recorded on this sheet
Collected
Père Faurie (Revd.) 1897-08-16
Origin
JP
The sheet
View the digitised specimen (CC BY 4.0)

A real pressed plant, in a real collection, under the accession number above. Not an illustration of one. The holding institution does not serve this sheet’s image to third parties, so there is no photograph here. The record is real and the link goes to it. Where we hold no openly licensed sheet for a species this section is simply absent, and where a sheet never recorded who determined it, that field stays empty rather than being filled in. Roughly half of all herbarium sheets never recorded a determiner, which is ordinary.

Native range 13 botanical countries

Regions where Cynanchum rostellatum is native: Amur, China North-Central, China South-Central, China Southeast, Inner Mongolia, Japan, Khabarovsk, Korea, Kuril Is., Manchuria, Primorye, Qinghai, Tibet AmurChina North-CentralChina South-CentralChina SoutheastInner MongoliaJapanKhabarovskManchuriaPrimoryeQinghaiTibet Korea
Native distribution of Cynanchum rostellatum, 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
Amur AMU ASIA-TEMPERATE
China North-Central CHN
China South-Central CHC
China Southeast CHS
Inner Mongolia CHI
Japan JAP
Khabarovsk KHA
Korea KOR
Kuril Is. KUR
Manchuria CHM
Primorye PRM
Qinghai CHQ
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 129 in flower of 327 examined

Proportion of examined Cynanchum rostellatum in flower, by month
Month In flower Examined Share 95% interval
Jan 0 7 0% 0% to 35%
Feb 0 7 0% 0% to 35%
Mar 0 8 0% 0% to 32%
Apr 0 17 0% 0% to 18%
May 0 40 0% 0% to 9%
Jun 2 17 12% 3% to 34%
Jul 22 30 73% 56% to 86%
Aug 70 97 72% 63% to 80%
Sep 29 50 58% 44% to 71%
Oct 4 32 13% 5% to 28%
Nov 2 17 12% 3% to 34%
Dec 0 5 0% 0% to 43%

Peak flowering in Jul. Each bar is the share of Cynanchum rostellatum 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. 129 of 327 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 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.

Where it actually grows measured, from 1,475 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -23.8 °C -7.0 °C 2.3 °C
Warmest month, mean daily high 24.4 °C 28.6 °C 32.1 °C
Annual rainfall 524 mm 1,151 mm 1,743 mm
Rainfall in the driest quarter 10 mm 63 mm 221 mm

It is found where winters are severely cold. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 1,475 research-grade observations of Cynanchum rostellatum that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one. Climate from CHELSA V2.1 (Karger et al. 2017); occurrences from 10.15468/dl.cgje2x.

Also published as 8 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.

  • Cynanchum thunbergii K.P.Ma, J.H.Xue & Chepinoga
  • Metaplexis chinensis Decne.
  • Metaplexis japonica (Thunb.) Makino
  • Metaplexis japonica f. albiflora Honda
  • Metaplexis rostellata Turcz.
  • Metaplexis stauntonii Schult.
  • Pergularia japonica Thunb.
  • Urostelma chinense Bunge

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 MEJA. 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.