Cynanchum foetidum

Plate 1 figs. a–g · 1 observation

This species has been photographed under an open licence only 1 time, 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.

Cynanchum foetidum, photographed by Eugenio Padilla — fig. a Eugenio Padilla, CC BY-SA 4.0 / 2017-09-08 / obs. 10604349

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 4 botanical countries

Native distribution of Cynanchum foetidum, 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
Mexico Central	MXC	NORTHERN AMERICA
Mexico Northeast	MXE
Mexico Southeast	MXT
Mexico Southwest	MXS

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 59 in flower of 69 examined

82%

100%

94%

93%

Proportion of examined Cynanchum foetidum in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	0	1	too few examined
Feb	1	2	too few examined
Mar	0	0	too few examined
Apr	0	0	too few examined
May	0	1	too few examined
Jun	2	2	too few examined
Jul	9	11	82%	52% to 95%
Aug	17	17	100%	82% to 100%
Sep	16	17	94%	73% to 99%
Oct	13	14	93%	69% to 99%
Nov	0	1	too few examined
Dec	1	3	too few examined

Peak flowering in Aug. Each bar is the share of Cynanchum foetidum 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. 59 of 69 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 8 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.

Asclepias foetida Cav.
Cynanchum lignosum (Vail) Woodson
Pergularia laevis Sessé & Moc.
Roulinia foetida (Cav.) Standl.
Rouliniella foetida (Cav.) Vail
Rouliniella lignosa Vail
Telminostelma foetidum (Cav.) Fontella & E.A.Schwarz

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.