Cirsium perplexans

(Rocky Mountain Thistle)

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Cirsium perplexans, Divide Rd., Uncompahgre Plateau, Mesa Co. 4588

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Cirsium perplexans, Divide Rd., Uncompahgre Plateau, Mesa Co. 4542

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Cirsium perplexans, Divide Rd., Uncompahgre Plateau, Mesa Co. 4540

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Cirsium perplexans, Divide Rd., Uncompahgre Plateau, Mesa Co. 4581

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Basal leaf, Cirsium perplexans, Divide Rd., Uncompahgre Plateau, Mesa Co. 4546

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Stem leaf, Cirsium perplexans, Divide Rd., Uncompahgre Plateau, Mesa Co. 4578

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Cirsium perplexans, Divide Rd., Uncompahgre Plateau, Mesa Co. 4570

Scientific Name Cirsium perplexans USDA PLANTS Symbol CIPE5
Common Name Rocky Mountain Thistle, Adobe Hills Thistle ITIS Taxonomic Serial No. 36399
Family Asteraceae (Sunflower) SEINet
Reference
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Description Life zones and habitat: Shrublands and foothills (5000 to 8000 ft.); shale or clay soils in open sites in areas of woodlands, sagebrush scrub and roadsides.
Plant: Erect perennial or biennial 8 to 40 inches tall, one or more reddish stems with few to many branches, thinly-covered with soft hairs.
Leaves: Lower leaves oblanceolate, upper lanceolate and clasping; from 6 to 12 inches long and 0.8 to 2.4 inches wide; blades often unlobed and sometimes pinnatifid to about halfway to the middle with lobes broadly separated or dentate; upper leaves becoming small and bract-like; leaf surfaces with thin wooly hairs; slender, weak yellow spines.
Inflorescence: Few to many flower heads in an openly-branched array; rose or reddish-purple composite flower heads (rays absent) about 1-1/4 inches tall and wide; layered phyllaries are spreading to reflexed, with erose (fringed) edges, a white glutinose ridge in the middle and short spines.
Bloom Period: June and July.
References: "Flora of Colorado" by Jennifer Ackerfield, Flora of North America, Colorado Rare Plant Guide and Thistles of Colorado.
BONAP Distribution Map


Map Color Key
Colorado Status:
Native
Rare

© Tom Lebsack 2024

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