Cirsium canescens
(Prairie Thistle)
Cirsium canescens, Pawnee Buttes, Weld Co. 7732
Cirsium canescens, Pawnee Buttes, Weld Co. 7758
Cirsium canescens, Pawnee Buttes, Weld Co. 7738
Cirsium canescens, Pawnee Buttes, Weld Co. 7755
Cirsium canescens, Pawnee Buttes, Weld Co. 7745
Cirsium canescens, Pawnee Buttes, Weld Co. 7750
Cirsium canescens, Pawnee Buttes, Weld Co. 7747
| Scientific Name | Cirsium canescens | USDA PLANTS Symbol | CICA11 |
| Common Name | Prairie Thistle | ITIS Taxonomic Serial No. | 36350 |
| Family | Asteraceae (Sunflower) | SEINet Reference |
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| Description |
Life zones and habitat: Plains to montane (3500 to 9500 ft.); sandy or gravelly soils on prairies and in disturbed areas, and in mountain meadows and coniferous forests. Plant: Upright biennial, 16 to 32 inches tall. Leaves: Oblong to elliptic or obovate leaves 3/4 to 2-3/8 inches wide and 4 to 10 inches long (upper leaves reduced), deeply pinnatifid, with spines at the tip of each lobe; blue-green in color; very hairy (cob-webby) above, densely woolly-hairy below. Inflorescence: Open arrays (corymbs or racemes) of 1 to 10 or more flower heads; central disk florets are white or lavender-tinged, 3/4 to over 1 inch long; no ray flowers; involucre phyllaries with yellow upward- and outward-pointing spines on tips of outer row, with a whitish glutinous ridge below each tip. Bloom Period: June to September. References: "Flora of Colorado" by Jennifer Ackerfield, SEINet and "Thistles of Colorado" by Larimer County Weed Distict. |
BONAP Distribution Map Map Color Key |
Colorado Status: Native |
© Tom Lebsack 2024
Banner photo: Castilleja rhexifolia and a brewing storm over the San Juan Mountains