Carduus acanthoides - L.
Spiny Plumeless-thistle
Other English Common Names: Plumeless Thistle
Other Common Names: spiny plumeless thistle
Taxonomic Status: Accepted
Related ITIS Name(s): Carduus acanthoides L. (TSN 35785)
French Common Names: chardon épineux
Unique Identifier: ELEMENT_GLOBAL.2.128178
Element Code: PDAST1S010
Informal Taxonomy: Plants, Vascular - Flowering Plants - Aster Family
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Asterales Asteraceae Carduus
Check this box to expand all report sections:
Concept Reference
Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Carduus acanthoides
Taxonomic Comments: Flora of North America (vol. 19, 2006) recognizes two varieties, one of which occurs in North America.
Conservation Status

NatureServe Status

Global Status: GNR
Global Status Last Changed: 22Mar1994
Rounded Global Status: GNR - Not Yet Ranked
Nation: United States
National Status: NNA
Nation: Canada
National Status: NNA (02Nov2012)

U.S. & Canada State/Province Status
United States California (SNA), Colorado (SNA), Connecticut (SNA), Delaware (SNA), Idaho (SNA), Illinois (SNA), Iowa (SNA), Kansas (SNA), Kentucky (SNA), Maine (SNA), Maryland (SNA), Massachusetts (SNR), Michigan (SNA), Minnesota (SNA), Montana (SNA), Nebraska (SNA), New Jersey (SNA), New York (SNA), North Carolina (SNA), North Dakota (SNA), Ohio (SNA), Oklahoma (SNA), Pennsylvania (SNA), Rhode Island (SNA), South Dakota (SNA), Vermont (SNA), Virginia (SNA), Washington (SNA), West Virginia (SNA), Wisconsin (SNA), Wyoming (SNA)
Canada British Columbia (SNR), New Brunswick (SNA), Newfoundland Island (SNA), Nova Scotia (SNA), Ontario (SNA), Quebec (SNA)

Other Statuses

NatureServe Global Conservation Status Factors

Other NatureServe Conservation Status Information

U.S. States and Canadian Provinces
Color legend for Distribution Map
NOTE: The distribution shown may be incomplete, particularly for some rapidly spreading exotic species.

U.S. & Canada State/Province Distribution
United States CAexotic, COexotic, CTexotic, DEexotic, IAexotic, IDexotic, ILexotic, KSexotic, KYexotic, MA, MDexotic, MEexotic, MIexotic, MNexotic, MTexotic, NCexotic, NDexotic, NEexotic, NJexotic, NYexotic, OHexotic, OKexotic, PAexotic, RIexotic, SDexotic, VAexotic, VTexotic, WAexotic, WIexotic, WVexotic, WYexotic
Canada BC, NBexotic, NFexotic, NSexotic, ONexotic, QCexotic

Range Map
No map available.

Ecology & Life History Not yet assessed
Economic Attributes
Economically Important Genus: Y
Management Summary Not yet assessed
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank)
Disclaimer: While I-Rank information is available over NatureServe Explorer, NatureServe is not actively developing or maintaining these data. Species with I-RANKs do not represent a random sample of species exotic in the United States; available assessments may be biased toward those species with higher-than-average impact.

I-Rank: Medium/Low
Rounded I-Rank: Medium
I-Rank Reasons Summary: Carduus acanthoides does not appear to be as widespread as C. nutans and therefore is having less of an affect US biodiversity. It is also a less well studied species. Like C. nutans, C. acanthoides has a biennial life cycle which does performs well in disturbed areas, but is limited by competition from natives.
Subrank I - Ecological Impact: Medium/Insignificant
Subrank II - Current Distribution/Abundance: Medium
Subrank III - Trend in Distribution/Abundance: High/Medium
I-Rank Review Date: 18Aug2004
Evaluator: Fellows, M.
Native anywhere in the U.S?
Native Range: Native throughout Europe, from the British Isles to the Mediterranean, east to temperate Asia (Weber 2003).

Download "An Invasive Species Assessment Protocol: Evaluating Non-Native Plants for their Impact on Biodiversity". (PDF, 1.03MB)
Provide feedback on the information presented in this assessment

Screening Questions

S-1. Established outside cultivation as a non-native? YES
Comments: (Kartesz 1999).

S-2. Present in conservation areas or other native species habitat? Yes
Comments: (APRS Implementation Team 2001).

Subrank I - Ecological Impact: Medium/Insignificant

1. Impact on Ecosystem Processes and System-wide Parameters:Low significance
Comments: May affect water availability to native plants (APRS Implementation Team 2001).

2. Impact on Ecological Community Structure:Medium/Low significance
Comments: Herbaceous (Kartesz 1999). Can form dense stands (Weber 2003). May be 40 cm in diameter, with roots 40 cm or more deep into the soil (CDFA 2004).

3. Impact on Ecological Community Composition:Medium/Low significance
Comments: A successful (APRS Implementation Team 2001) and aggressive competitor (Noxious Weed Control Authority). Dense stands tend to be species poor (Weber 2003).

4. Impact on Individual Native Plant or Animal Species:Unknown

5. Conservation Significance of the Communities and Native Species Threatened:Low significance/Insignificant
Comments: Disturbed areas, including: roadsides, pastures and river valleys (Colorado Weed Management Association 2000; CDFA 2004).

Subrank II. Current Distribution and Abundance: Medium

6. Current Range Size in Nation:High/Moderate significance
Comments: Kartesz (1999) reports a scattered distribution throughout the US from California to New York. Thought to be limited to specific regions, for example, in California, known from Eastern North Coast Ranges, northern Sierra Nevadas, Modoc Plateau and the San Francisco Bay region (CDFA 2004).

7. Proportion of Current Range Where the Species is Negatively Impacting Biodiversity:Low significance
Comments: State level noxious weed in at least 9 states (Kartesz 1999) but most of these impacts appear to be associated with agriculture.

8. Proportion of Nation's Biogeographic Units Invaded:High/Moderate significance
Comments: Kartesz (1999) reports a scattered distribution throughout the US from California to New York. This suggests that C. acanthoides may occur in at least 19 and maybe over 50% of the US region's ecoregions (TNC 2001).

9. Diversity of Habitats or Ecological Systems Invaded in Nation:High/Moderate significance
Comments: Disturbed areas, including: roadsides, pastures and river valleys (Colorado Weed Management Association 2000).

Subrank III. Trend in Distribution and Abundance: High/Medium

10. Current Trend in Total Range within Nation:High/Low significance
Comments: Several sources cite the ability of C. acanthoides to increase, along with the ability to colonize disturbed areas, it is inferred this species is not declining in range.

11. Proportion of Potential Range Currently Occupied:Moderate significance
Comments: "Has the potential to become just as widely spread" as Carduus nutans (Noxious Weed Control Authority).

12. Long-distance Dispersal Potential within Nation:High significance
Comments: "Great potential for long-distance dispersal" (APRS Implementation Team 2001). Although 99% of seeds fall within 50 m of the parent plant, 1% of seed disperses as a result of wind or water movement, birds, small mammals and human activities (CDFA 2004).

13. Local Range Expansion or Change in Abundance:High/Moderate significance
Comments: "Rapidly increasing" in Colorado (Colorado Weed Management Association 2000).

14. Inherent Ability to Invade Conservation Areas and Other Native Species Habitats:Low significance
Comments: Follows disturbance (APRS Implementation Team 2001).

15. Similar Habitats Invaded Elsewhere:Low significance
Comments: Present in disturbed areas in Canada such as roadsides and pastures (Harris 2003). Also present in New Zealand, Chile and Argenina in similar habitats (Weber 2003).

16. Reproductive Characteristics:High significance
Comments: Produces many (> 1000) seeds, sometimes more than once a year that can remain viable for more than 5 years (APRS Implementation Team 2001). Seed bank may disintegrate after 3 years becuase of germination, decomposition and/or seed predation (CDFA 2004). Can resprout from root crown (Noxious Weed Control Authority; CDFA 2004).

17. General Management Difficulty:Not ranked

18. Minimum Time Commitment:Not ranked

19. Impacts of Management on Native Species:Not ranked

20. Accessibility of Invaded Areas:Not ranked

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

  • Alien plants ranking system (APRS) Implementation Team. 2001a. Alien plants ranking system version 7.1. Southwest Exotic Plant Information Clearinghouse, Flagstaff, AZ. Online. Available: (accessed 2004).

  • California Department of Food and Agricutlure (CDFA). 2004. Noxious Weed Data Sheet. Carduus genus. Available ONLINE: Accessed 2004.

  • Colorado Weed Management Association (CWMA). 2000. Noxious weeds and non-native plant factsheets. Available: (Accessed 2004).

  • Flora of North America Editorial Committee. 2006a. Flora of North America North of Mexico. Vol. 19. Magnoliophyta: Asteridae, part 6: Asteraceae, part 1. Oxford University Press, New York. xxiv + 579 pp.

  • Harris, P. 2003. Nodding and plumeless thistle Carduus nutans L. and C. acanthoides L. Classical Biological Control of Weeds Biology of Target Weeds. Agriculture and Agri-Food Canada. Available Online: Accesed 2004.

  • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

  • Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.

  • Noxious Weed Control Authority. Undated. Nebraska Noxious Weeds. Available Online: Accessed 2004.

  • The Nature Conservancy. 2001. Map: TNC Ecoregions of the United States. Modification of Bailey Ecoregions. Online . Accessed May 2003.

  • Weber, E. 2003. Invasive plant species of the world: a reference guide to environmental weeds. CABI Publishing, Cambridge, Massachusetts. 548 pp.

Use Guidelines & Citation

Use Guidelines and Citation

The Small Print: Trademark, Copyright, Citation Guidelines, Restrictions on Use, and Information Disclaimer.

Note: All species and ecological community data presented in NatureServe Explorer at were updated to be current with NatureServe's central databases as of November 2016.
Note: This report was printed on

Trademark Notice: "NatureServe", NatureServe Explorer, The NatureServe logo, and all other names of NatureServe programs referenced herein are trademarks of NatureServe. Any other product or company names mentioned herein are the trademarks of their respective owners.

Copyright Notice: Copyright © 2017 NatureServe, 4600 N. Fairfax Dr., 7th Floor, Arlington Virginia 22203, U.S.A. All Rights Reserved. Each document delivered from this server or web site may contain other proprietary notices and copyright information relating to that document. The following citation should be used in any published materials which reference the web site.

Citation for data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2017. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available (Accessed:

Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:

Full metadata for the Mammal Range Maps of North America is available at:

Restrictions on Use: Permission to use, copy and distribute documents delivered from this server is hereby granted under the following conditions:
  1. The above copyright notice must appear in all copies;
  2. Any use of the documents available from this server must be for informational purposes only and in no instance for commercial purposes;
  3. Some data may be downloaded to files and altered in format for analytical purposes, however the data should still be referenced using the citation above;
  4. No graphics available from this server can be used, copied or distributed separate from the accompanying text. Any rights not expressly granted herein are reserved by NatureServe. Nothing contained herein shall be construed as conferring by implication, estoppel, or otherwise any license or right under any trademark of NatureServe. No trademark owned by NatureServe may be used in advertising or promotion pertaining to the distribution of documents delivered from this server without specific advance permission from NatureServe. Except as expressly provided above, nothing contained herein shall be construed as conferring any license or right under any NatureServe copyright.
Information Warranty Disclaimer: All documents and related graphics provided by this server and any other documents which are referenced by or linked to this server are provided "as is" without warranty as to the currentness, completeness, or accuracy of any specific data. NatureServe hereby disclaims all warranties and conditions with regard to any documents provided by this server or any other documents which are referenced by or linked to this server, including but not limited to all implied warranties and conditions of merchantibility, fitness for a particular purpose, and non-infringement. NatureServe makes no representations about the suitability of the information delivered from this server or any other documents that are referenced to or linked to this server. In no event shall NatureServe be liable for any special, indirect, incidental, consequential damages, or for damages of any kind arising out of or in connection with the use or performance of information contained in any documents provided by this server or in any other documents which are referenced by or linked to this server, under any theory of liability used. NatureServe may update or make changes to the documents provided by this server at any time without notice; however, NatureServe makes no commitment to update the information contained herein. Since the data in the central databases are continually being updated, it is advisable to refresh data retrieved at least once a year after its receipt. The data provided is for planning, assessment, and informational purposes. Site specific projects or activities should be reviewed for potential environmental impacts with appropriate regulatory agencies. If ground-disturbing activities are proposed on a site, the appropriate state natural heritage program(s) or conservation data center can be contacted for a site-specific review of the project area (see Visit Local Programs).

Feedback Request: NatureServe encourages users to let us know of any errors or significant omissions that you find in the data through (see Contact Us). Your comments will be very valuable in improving the overall quality of our databases for the benefit of all users.