Cirsium scariosum

(Meadow Thistle)


Cirsium scariosum, Middle Swan River, Summit Co. 5611


Cirsium scariosum, Middle Swan River, Summit Co. 5608


Cirsium eatonii var. eriocephalum, Mosquito Pass, Park Co. 2933

Scientific Name Cirsium scariosum USDA PLANTS Symbol CISC2
Common Name Meadow Thistle ITIS Taxonomic Serial No. 36143
Family Asteraceae (Sunflower) SEINet
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Description Life zones and habitat: Montane to subalpine (7000 to 12500 ft.); moist open areas; meadows, along streams and roadsides.
Plant: Stemless or upright biennial/perennial, up to 40 inches tall; fleshy, thick single or multiple stalks branched from near base.
Leaves: Basal and stem leaves, linear to elliptic 4 to 16 inches long, very wavy, shallow or deeply pinnately-lobed with a broad central midstrip; sessile; smooth above and woolly-hairy below; spiney.
Inflorescence: Dense clusters of one to many flower heads; white to light lavender disk florets 3/4 to 1-3/8 inches long; pointed phyllaries with spines and teeth; no ray flowers.
Bloom Period: June to September.
References: "Flora of Colorado" by Jennifer Ackerfield and others.
BONAP Distribution Map

Map Color Key
Colorado Status:

© Tom Lebsack 2022

Banner photo: Ten Mile Range and Rhodiola integrifolia (King’s Crown) in Summit County