Carduus acanthoides (plumeless thistle)

Carduus acanthoides

Photo courtesy Joseph DiTomaso

Carduus acanthoides (plumeless thistle) is a tall biennial (family Asteraceae) with spiny leaves that colonizes disturbed open sites, roadsides, pastures, annual grasslands, and waste areas. It can inhibit growth of native plants in its vicinity. Plumeless thistle is uncommon in California, and the California Department of Food and Agriculture has an active program to control known populations.

Cal-IPC Inventory rating: Limited

Cal-IPC Resources on Carduus acanthoides

• California Invasive Plant Inventory Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.
• CalWeedMapper - Statewide maps, climate models, and reports.
• Cal-IPC News - Articles from our quarterly newsletter. List of articles on Carduus acanthoides.
• Cal-IPC Symposium Proceedings - Presentations and papers from our annual Symposium. List of articles on Carduus acanthoides.

Cal-IPC News Articles

• (1993). California Exotic Pest Plant Council draft list exotic plants of greatest concern October 1993. CalEPPC News. 1: 6.
• Pitcairn, M. (2000). All weeds that have approved biological control agents, accidental introductions and others. CalEPPC News. 8.
• Richardson, B. (2004). The A-rated north. Cal-IPC News. 12: 4-5,14.

Cal IPC Symposium Proceedings

• Carrithers, V., B. Miller, et al. (2005). Aminopyralid: A new reduced risk active ingredient for control of broadleaf invasive and noxious weeds. California Invasive Plant Council Symposium 2005. Chico, CA.
• Cooper, V. K. and B. J. Moritsch (1999). Weeding the wilderness: Non-native plant management at Point Reyes National Seashore. California Exotic Pest Plant Council Symposium '99. Sacramento, CA.
• O'Connell, R. A. (1997). Hydrilla: A case study: The state of California's noxious weed eradication programs. California Exotic Pest Plant Council Symposium '97. Concord, CA.
• O'Connell, R. A. (1999). The state of California's noxious weed eradication programs. California Exotic Pest Plant Council. Sacramento, CA.

Other Resources on Carduus acanthoides

• USDA PLANTS database - Federal database with information on identification and distribution, and links to websites in individual states.
• Jepson Online Interchange for California Flora - Information on taxonomy, biology, and distribution from the UC Berkeley Jepson Herbarium.
• CalFlora - Distribution information by county based on submitted observations and herbarium specimens.
• Encycloweedia - Plants rated as noxious weeds by the California Department of Food and Agriculture.
• CalPhotos - Images of plants taken mostly in California.
• Natural Resource Projects Inventory - State database with information on resource management projects throughout California. Query by the species of interest.

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