Distribution: Occurring east of the Cascades crest in northeastern Washington; British Columbia to Washington, also in California, east to the northern Rocky Mountains, Great Plains, and eastern North America.
Habitat: Roadsides, fields, ditches, and other disturbed, open areas.
Flowers: July-October
Origin: Introduced from Europe
Growth Duration: Biennial
Conservation Status: Not of concern
Pollination: Bees, flies, beetles, wasps
Biennial herb 3-15 dm. tall, the stem tough and strongly spiny.
Leaves deeply lobed to pinnatifid, up to 25 cm. long and 8 cm. wide, the midrib beneath covered with long, soft hairs.
Heads clustered or solitary at the ends of the branches, erect, the disk mostly 1.5-2.5 cm. wide; involucre bracts narrow, under 2 mm. wide, erect, the middle and outer bracts spine-tipped, the inner softer and scarcely spiny; flowers purple; pappus capillary, not plumose.
Achenes glabrous.
PNW Herbaria: Specimen records of Carduus acanthoides in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Carduus acanthoides checklist entry
OregonFlora: Carduus acanthoides information
E-Flora BC: Carduus acanthoides atlas page
CalPhotos: Carduus acanthoides photos