- Carduus pycnocephalus is an annual or sometimes biennial plant. It can grow from 1-4 ft. (0.3-1.2 m) tall.
- The stems have spiny wings. Leaves deeply cut into 2 to 5 pairs of lobes, have white spots and undersurface slightly woolly.
- The flowers range from purplish to pinkish, are borne in cylindrical heads either solitary or in clusters of more than 5. The bracts hairy. It blooms from May to June.
- Fruits from outer part of flower head are gray in color and inner portion are yellowish to tan.
- Ecological Threat
- Carduus pycnocephalus is native to southern Europe. It infests roadsides and waste areas, and has become a major problem on hill pasture land in Douglas County, Oregon. Once established, it spreads rapidly and forms dense stands which displace more desirable vegetation and exclude livestock.
Carduus pycnocephalus, a member of the Thistle tribe of the Composite family, is an erect winter annual herb 3-18 dm tall.
Carduus pycnocephalus can be distinguished from other thistle species by its relatively small and few terminal flowerheads and narrow phyllaries with copious tiny, firm, forward-pointing hairs, especially on the midrib (Hitchcock and Cronquist 1973).
- Element Stewardship Abstract - The Nature Conservancy
Image Sets View other image sets:
EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org
State Invasive List - This map identifies those states that list this species on their invasive species list. For more information, visit Invasive.org
Invasive Listing Sources
- California Invasive Plant Council
- California Noxious Weeds
- Faith Campbell, 1998
- Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
- Oregon Noxious Weeds
- Pacific Northwest Exotic Pest Plant Council, 1998
- Washington Noxious Weeds
- WeedUS - Database of Plants Invading Natural Areas in the United States
|Common Name Reference:|| USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|
|Scientific Name Reference:||USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|