|Scientific Name||Cirsium arvense||USDA PLANTS Symbol||CIAR4|
|Common Name||Canada Thistle||ITIS Taxonomic Serial No.||36335|
Life zones and habitat: Plains to montane (4000 to 9800 ft.); disturbed areas, pastures, roadsides, croplands.
Plant: Erect perennial, 1 to 4 feet tall; stems are grooved and branched near the top.
Leaves: Oblong to elliptic, 1 to 12 inches long, with edges entire, shallow or deeply-pinnately-lobed with spines.
Inflorescence: Lavender composite flower heads about 1-inch across; green to purplish bracts. Male and female flowers on separate plants.
Bloom Period: June to September.
References: "Flora of Colorado" by Jennifer Ackerfield, "Wildflowers of the Rocky Mountains" by Carl Schreier and SEINet.
|BONAP Distribution Map
Map Color Key
© Tom Lebsack 2022
Banner photo: Ten Mile Range and Rhodiola integrifolia (King’s Crown) in Summit County