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Montana Field Guide

Montana Field Guides

Gray Green Thistle - Cirsium canovirens
Other Names:  Cirsium cymosum, Cirsium subniveum, Cirsium inamoenum

Native Species

Global Rank: G4G5
State Rank: S3S4
(see State Rank Reason below)

Agency Status
MNPS Threat Rank:
C-value: 4

External Links

State Rank Reason (see State Rank above)
Cirsium canovirens is treated as a variety (Cirsium cymosum variety canovirens) by the Flora of North America (FNA 2006). Whether treated at the species or variety level this plant occurs in southwest Montana where it is fairly common. In general thistles are under-collected, and more location data would be welcomed.
  • Details on Status Ranking and Review
    Gray Green Thistle (Cirsium canovirens) Conservation Status Review
    Review Date = 08/08/2017
    View State Conservation Rank Criteria
    Population Size

    ScoreC - 250 - 1,000 individuals

    Range Extent

    ScoreD - 1,000-5,000 sq km (~400-2,000 sq mi)

    Area of Occupancy

    ScoreC - 3-5 4-km2 grid cells

    Number of Populations

    ScoreB - 6 - 20

    Number of Occurrences or Percent Area with Good Viability / Ecological Integrity

    ScoreC - Few (4-12) occurrences with excellent or good viability or ecological integrity

    Environmental Specificity

    ScoreC - Moderate. Generalist or community with some key requirements scarce


    ScoreD - Low

    CommentNo known threats.

General Description
Taprooted biennial. Stems erect, branched above or not, 30–100 cm, sometimes with spiny wings from leaf bases. Herbage tomentose to arachnoid, upper leaf surfaces sometimes sparsely so. Leaves short-petiolate; blade linear-oblanceolate, 8–25 cm long, pinnately lobed, becoming clasping or decurrent upward. Inflorescence heads 1 to few at tips of peduncles forming corymbiform arrays; peduncles 1–8 cm long. Involucres broadly campanulate, 15–30 mm high, sparsely arachnoid-tomentose; phyllaries imbricate in 6 to 10 series, green, linear-lanceolate; sometimes with a darkened, often resinous midvein; spines 2–6 mm long, spreading. Disk corollas white to light purple, 15–26 mm long. Achenes 5–8 mm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range

Range Comments
OR to MT to CA, NV and WY (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 59

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



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

Sagebrush steppe, grasslands, open forest; montane, subalpine (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

  • Literature Cited AboveLegend:   View Online Publication
    • Cronquist, A., A.H. Holmgren, N.H. Holmgren, J.L. Reveal, and P.K. Holmgren. 1994. Intermountain Flora: Vascular Plants of the Intermountain West. Asterales. U.S.A., Volume 5. Published for The New York Botanical Garden, Bronx, New York.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
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Citation for data on this website:
Gray Green Thistle — Cirsium canovirens.  Montana Field Guide.  .  Retrieved on , from