Centaurea asperaL.

rough star-thistle

WFO wfo-0000016988 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Centaurea aspera, photographed by Pete Bradshaw
fig. a Pete Bradshaw, CC BY 4.0 / 2022-06-08 / obs. 204423738

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
02031352
Filed as
Centaurea aspera L.
Det. by
not recorded on this sheet
Collected
A. Brown 1880-07-02
Origin
US
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 10 botanical countries

Regions where Centaurea aspera is native: Canary Is., Morocco, Baleares, Corse, France, Italy, Portugal, Sardegna, Sicilia, Spain MoroccoCorseFranceItalyPortugalSiciliaSpain Canary Is.BalearesSardegna
Native distribution of Centaurea aspera, 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
Baleares BAL EUROPE
Corse COR
France FRA
Italy ITA
Portugal POR
Sardegna SAR
Sicilia SIC
Spain SPA
Canary Is. CNY AFRICA
Morocco MOR

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 298 in flower of 319 examined

Proportion of examined Centaurea aspera in flower, by month
Month In flower Examined Share 95% interval
Jan 9 11 82% 52% to 95%
Feb 9 15 60% 36% to 80%
Mar 7 8 88% 53% to 98%
Apr 23 28 82% 64% to 92%
May 58 60 97% 89% to 99%
Jun 44 44 100% 92% to 100%
Jul 22 23 96% 79% to 99%
Aug 23 25 92% 75% to 98%
Sep 24 25 96% 80% to 99%
Oct 39 39 100% 91% to 100%
Nov 28 28 100% 88% to 100%
Dec 12 13 92% 67% to 99%

Peak flowering in Jun. Each bar is the share of Centaurea aspera 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. 298 of 319 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 2,010 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -0.5 °C 4.6 °C 8.9 °C
Warmest month, mean daily high 22.0 °C 27.4 °C 31.2 °C
Annual rainfall 327 mm 648 mm 944 mm
Rainfall in the driest quarter 26 mm 97 mm 148 mm

It is found where winters bring light frost. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 2,010 research-grade observations of Centaurea aspera 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 29 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.

  • Alophium tenuifolium Cass.
  • Calcitrapa aspera (L.) Cass.
  • Calcitrapa heterophylla Moench
  • Calcitrapa parviflora Lam.
  • Calcitrapoides aspera (L.) Holub
  • Calcitrapoides gentilii (Braun-Blanq. & Maire) Holub
  • Calcitrapoides heterophylla (Willd.) Holub
  • Calcitrapoides stenophylla (Dufour) Holub
  • Centaurea alophium DC.
  • Centaurea aspera var. aspera
  • Centaurea aspera var. parcespinosa Sennen
  • Centaurea aspera var. praetermissa DC.
  • Centaurea aspera var. subinermis DC.
  • Centaurea auriculata Balb. ex Pers.
  • Centaurea diversifolia Lag. ex Boiss.
  • Centaurea fragilis var. integrifolia Ball
  • Centaurea gentilii Braun-Blanq. & Maire
  • Centaurea gentilii var. ecillata Maire
  • Centaurea gentilii var. gentilii
  • Centaurea gentilii var. integrifolia (Ball) Emb. & Maire
  • Centaurea heterophylla Willd.
  • Centaurea isnardii L.
  • Centaurea parviflora Lam.
  • Centaurea praetermissa Martrin-Donos

and 5 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. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. 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.