Carduus defloratusL.

WFO wfo-0000134427 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Carduus defloratus, photographed by Elias
fig. a Elias, CC BY 4.0 / 2022-06-05 / obs. 203514581

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
The New York Botanical Garden
Accession
02064958
Filed as
Carduus defloratus L.
Det. by
not recorded on this sheet
Collected
J. Morier-Genoud 2010-05-10
Origin
CH
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 12 botanical countries

Regions where Carduus defloratus is native: Austria, Czechia-Slovakia, France, Germany, Hungary, Italy, NW. Balkan Pen., Poland, Romania, Spain, Switzerland, Ukraine AustriaCzechia-SlovakiaFranceGermanyHungaryItalyNW. Balkan Pen.PolandRomaniaSpainSwitzerlandUkraine
Native distribution of Carduus defloratus, 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.
RegionTDWG codeContinent
Austria AUT EUROPE
Czechia-Slovakia CZE
France FRA
Germany GER
Hungary HUN
Italy ITA
NW. Balkan Pen. YUG
Poland POL
Romania ROM
Spain SPA
Switzerland SWI
Ukraine UKR

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 427 in flower of 464 examined

Proportion of examined Carduus defloratus in flower, by month
Month In flower Examined Share 95% interval
Jan 0 1 too few examined
Feb 0 0 too few examined
Mar 1 2 too few examined
Apr 1 2 too few examined
May 14 20 70% 48% to 85%
Jun 59 73 81% 70% to 88%
Jul 164 174 94% 90% to 97%
Aug 106 109 97% 92% to 99%
Sep 45 45 100% 92% to 100%
Oct 28 29 97% 83% to 99%
Nov 8 8 100% 68% to 100%
Dec 1 1 too few examined

Peak flowering in Sep. Each bar is the share of Carduus defloratus 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. 427 of 464 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 5 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.

Where it actually grows measured, from 2,027 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -16.6 °C -10.7 °C -4.3 °C
Warmest month, mean daily high 13.1 °C 17.2 °C 22.4 °C
Annual rainfall 916 mm 1,579 mm 2,526 mm
Rainfall in the driest quarter 132 mm 267 mm 491 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 2,027 research-grade observations of Carduus defloratus 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 51 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 argemone Lam.
  • Carduus argemone subsp. argemone
  • Carduus argemone subsp. obtusisquamus Franco
  • Carduus axillaris Gaudin
  • Carduus barrelieri Bertol. ex Nyman
  • Carduus barrelieri Bertol.
  • Carduus carlinaefolius Nyman
  • Carduus carlinifolius Lam.
  • Carduus carlinifolius subsp. carlinifolius
  • Carduus carlinifolius subsp. paui (Devesa & Talavera) Mateo
  • Carduus carlinifolius subsp. timbalii Franco
  • Carduus cirsioides Vill.
  • Carduus crassifolius Willd.
  • Carduus crassifolius subsp. crassifolius
  • Carduus crassifolius subsp. glaucus (Rchb.f.) Kazmi
  • Carduus crassifolius var. crassifolius
  • Carduus crassifolius var. glaucus Rchb.f.
  • Carduus defloratus subsp. argemone (Pourr. ex Lam.) O.Bolòs & Vigo
  • Carduus defloratus subsp. crassifolius (Willd.) Hayek
  • Carduus defloratus subsp. medioformis (Rouy) Braun-Blanq. & al.
  • Carduus defloratus subsp. spinulosus (Bertol.) Nyman
  • Carduus defloratus subsp. tridentinus (Evers) Ladurner
  • Carduus defloratus subsp. viridis (A.Kern.) Nyman
  • Carduus defloratus var. defloratus

and 27 more.

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. 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.