spiny plumeless thistle USDA PLANTS Symbol: CAAC
U.S. Nativity: Exotic
Habit: Forbs/Herbs
Carduus acanthoides L.

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Taxonomic Rank: Magnoliopsida: Asterales: Asteraceae
Synonym(s): plumeless thistle
Native Range: Temp. Asia, Europe (GRIN);

Appearance
Carduus acanthoides is an annual or biennial herbaceous plant that grows to 5 ft. (1.5 m) tall.
Foliage
This thistle may exceed two meters in height and can form weedy monotypic stands. The stem and foliage are spiny and sometimes woolly.
Flowers
Flowering occurs from May to August. The flower heads are reddish-purple in color and up to 1 in. (2.5 cm) in diameter. Flower stems are branched with spiny wings extending to the flower heads.
Fruit
Seeds are oblong, striate, and slightly curved.
Ecological Threat
Carduus acanthoides infests open, disturbed areas such as pastures, roadsides, and railroad right-of-ways. It can form thick stands that reduce the forage potential of pastures and suppress the growth of desirable vegetation.

Identification, Biology, Control and Management Resources

Selected Images from Invasive.orgView All Images at Invasive.org


Flower(s);
Gary L. Piper, Washington State University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Gary L. Piper, Washington State University, Bugwood.org
Additional Resolutions & Image Usage

Foliage;
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s); in flower
Todd Pfeiffer, Klamath County Weed Control, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Todd Pfeiffer, Klamath County Weed Control, Bugwood.org
Additional Resolutions & Image Usage

Foliage;
Todd Pfeiffer, Klamath County Weed Control, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Todd Pfeiffer, Klamath County Weed Control, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Todd Pfeiffer, Klamath County Weed Control, Bugwood.org
Additional Resolutions & Image Usage

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org
 


State(s) Where Reported invasive.
Based on state level agency and organization lists of invasive plants from WeedUS database.

U.S. National Parks where reported invasive:
Theodore Roosevelt National Park (North Dakota)
Yellowstone National Park (Wyoming)



Invasive Listing Sources:
California Invasive Plant Council
Faith Campbell, 1998
Hoffman, R. & K. Kearns, Eds. 1997. Wisconsin manual of control recommendations for ecologically invasive plants. Wisconsin Dept. Natural Resources, Bureau of Endangered Resources. Madison, Wisconsin. 102pp.
Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
Mid-Atlantic Exotic Pest Plant Council, 2005
New Jersey Department of Agriculture, Division of Plant Industry, 2004
Pacific Northwest Exotic Pest Plant Council, 1998
Tennessee Exotic Pest Plant Council