Cirsium fontinale (fountain thistle)

Plate 1 figs. a–e · 2 observations

This species has been photographed under an open licence only 2 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.

Cirsium fontinale, photographed by Annette Herz — fig. a Annette Herz, CC BY 4.0 / 2021-04-03 / obs. 118882409

Cirsium fontinale, photographed by Chuck Wilson — fig. b Chuck Wilson, CC0 1.0 / obs. 189259308

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 1 botanical country

Native distribution of Cirsium fontinale, 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
California	CAL	NORTHERN AMERICA

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 230 in flower of 409 examined

13%

33%

26%

83%

94%

87%

57%

29%

33%

Proportion of examined Cirsium fontinale in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	1	8	13%	2% to 47%
Feb	2	16	13%	4% to 36%
Mar	15	46	33%	21% to 47%
Apr	22	85	26%	18% to 36%
May	101	121	83%	76% to 89%
Jun	44	47	94%	83% to 98%
Jul	27	31	87%	71% to 95%
Aug	8	14	57%	33% to 79%
Sep	0	5	0%	0% to 43%
Oct	7	24	29%	15% to 49%
Nov	3	9	33%	12% to 65%
Dec	0	3	too few examined

Peak flowering in Jun. Each bar is the share of Cirsium fontinale 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. 230 of 409 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. One month has fewer than 5 examined observations, so no proportion is drawn for it. 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 3 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.

Carduus fontinalis Greene
Cirsium campylon H.Sharsm.
Cnicus fontinalis Greene

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.
Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
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.