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Species
Information
- slender-flowered thistle (winged
plumeless thistle)
- Carduus
tenuiflorus W.
Curtis
- USDA
Symbol: CATE2
- Oregon
Noxious Weed Designation: B
- Pictures
Identification: Annual or sometimes biennial; blooms May to June. Grows 1 to 4 ft tall. Stems have spiny wings. Leaves deeply cut into 2 to 5 pairs of lobes and undersurface slightly woolly. Flowers purplish to pinkish, borne in cylindrical heads either solitary or in clusters of 2 to 5. Bracts hairy; fruits from outer part of flower head gray, inner portion are yellowish to tan. Nearly identical to Italian thistle, but has larger clusters of flower heads.
Impacts: Slender-flowered thistle 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.
Biological
Controls: Two approved biocontrol agents, a seed head weevil and a stem-boring fly, have been successfully established in Oregon.
Oregon
Maps of Slender-flowered Thistle Distribution
Links:
USDA
Plants Database information on slender-flowered thistle
GRIN
Database information on slender-flowered thistle
Oregon Department
of Agriculture information on slender-flowered thistle
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