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Montana Field Guide

Montana Field Guides

Hooker Thistle - Cirsium hookerianum


Global Rank: G5
State Rank: S4S5

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value:

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General Description
Taprooted biennial. Stems erect, often unbranched, 25–90 cm. Herbage thinly to moderately arachnoid-tomentose; lower leaf surfaces usually whitish. Leaves short-petiolate; blades linear-oblanceolate to linear-lanceolate, 8–30 cm long, dentate to pinnately lobed. Inflorescence capitate or spike-like with usually 3 to 12 subsessile heads subtended by leaf-like bracts; peduncles 2 cm long. Involucres campanulate, 2–3 cm high, arachnoid-tomentose across the phyllaries that are imbricate in 4 to 8 series, whitish to purplish, linear-lanceolate; sometimes with a darkened resinous keel; inner acuminate, ciliate; spines 3–5 mm long, erect. Disk corollas white to light purple, 20–25 mm long. Achenes 5–7 mm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range
Present
 


Range Comments
BC, AB south to WA, ID and WY (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Summary of Observations Submitted for Montana
Number of Observations: 16

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Meadows, grasslands, woodlands, open slopes; valleys to subalpine (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

References
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Citation for data on this website:
Hooker Thistle — Cirsium hookerianum.  Montana Field Guide.  .  Retrieved on , from