Eaton's Thistle - Cirsium eatonii
Taprooted perennial, often from a branched caudex. Stems erect, often unbranched, 10–70 cm. Herbage glabrate to arachnoid. Leaves short-petiolate; blade linear-lanceolate, 10–30 cm long with 10 to 20 pairs of shallow, closely-spaced lobes. Inflorescence capitate or spike-like with few, nearly sessile heads. Involucres broadly campanulate, 2–3 cm high, enclosed by uppermost leaves that obscure the phyllaries; phyllaries arachnoid especially on the margins, subequal in 4 to 5 series, green, linear-lanceolate; outer with spine-tips 7–10 mm long; inner acuminate. Disk corollas white, 17–23 mm long. Achenes 5–7 mm long (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX
Our plants are variety murdockii
OR to MT south to NV, UT and NM (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus vagans
, Bombus appositus
, Bombus auricomus
, Bombus bifarius
, Bombus borealis
, Bombus centralis
, Bombus fervidus
, Bombus flavifrons
, Bombus frigidus
, Bombus huntii
, Bombus mixtus
, Bombus nevadensis
, Bombus rufocinctus
, Bombus sylvicola
, Bombus ternarius
, Bombus terricola
, Bombus sitkensis
, Bombus occidentalis
, Bombus pensylvanicus
, Bombus bimaculatus
, Bombus griseocollis
, Bombus impatiens
, Bombus insularis
, Bombus suckleyi
, Bombus bohemicus
, and Bombus flavidus
(Thorp et al. 1983, Mayer et al. 2000, Wilson et al. 2010, Colla and Dumesh 2010, Colla et al. 2011, Koch et al. 2012, Williams et al. 2014, Tripoldi and Szalanski 2015).
- Literature Cited AboveLegend: View Online Publication
- Colla, S., L. Richardson, and P. Williams. 2011. Bumble bees of the eastern United States. Washington, DC: USDA Forest Service, Pollinator Partnership. 103 p.
- Colla, S.R. and S. Dumesh. 2010. The bumble bees of southern Ontario: notes on natural history and distribution. Journal of the Entomological Society of Ontario 141:39-68.
- Koch, J., J. Strange, and P. Williams. 2012. Bumble bees of the western United States. Washington, DC: USDA Forest Service, Pollinator Partnership. 143 p.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Mayer, D.F., E.R. Miliczky, B.F. Finnigan, and C.A. Johnson. 2000. The bee fauna (Hymenoptera: Apoidea) of southeastern Washington. Journal of the Entomological Society of British Columbia 97: 25-31.
- Thorp, R.W., D.S. Horning, and L.L. Dunning. 1983. Bumble bees and cuckoo bumble bees of California (Hymenoptera: Apidae). Bulletin of the California Insect Survey 23:1-79.
- Tripoldi, A.D. and A.L. Szalanski. 2015. The bumble bees (Hymenoptera: Apidae: Bombus) of Arkansas, fifty years later. Journal of Melittology 50: doi: http://dx.doi.org/10.17161/jom.v0i50.4834
- Williams, P., R. Thorp, L. Richardson, and S. Colla. 2014. Bumble Bees of North America. Princeton, NJ: Princeton University Press. 208 p.
- Wilson, J.S., L.E. Wilson, L.D. Loftis, and T. Griswold. 2010. The montane bee fauna of north central Washington, USA, with floral associations. Western North American Naturalist 70(2): 198-207.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- Aho, Ken Andrew. 2006. Alpine and Cliff Ecosystems in the North-Central Rocky Mountains. Ph.D. Dissertation. Bozeman, Montana: Montana State University. 343 p.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.