Cirsium ownbeyi
Author: Welsh

Ownbey's thistle

Asteraceae (Sunflower Family)

Close up of Cirsium ownbeyi by Delia Malone.
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Close up of Cirsium ownbeyi by Delia Malone.
Click image to enlarge.
Close up of Cirsium ownbeyi by Delia Malone.
Click image to enlarge.
Close up of Cirsium ownbeyi by Delia Malone.
Click image to enlarge.

Ranks and Status

Global rank: G3
State rank: S2
Federal protection status: None
State protection status: None

[+] Description and Phenology

Cirsium ownbeyi by Kaye H. Thorne
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General description: Taprooted perennial, 3-7 dm tall. Stems are lightly pubescent, spiny winged along internodes. Leaves are strongly decurrent, green, glabrous, thrice-compound into spiny, finely divided lobes. Upper-most leaves are reduced to spines. Involucre 1.8-2.5 cm high, bracts lightly pubescent on margins only, spine-tipped. Flower heads at tip of stem, not densely clustered, but hidden in a mass of spines. Flowers white to rose pink or lavender (Spackman et al. 1997, Weber and Wittmann 2012, Ackerfield 2015).

Look Alikes: Cirsium calcareum leaves are tomentose at least beneath, rarely almost glabrous. Cirsium eatonii has densely cobwebby-pubescent involucre bracts (Spackman et al. 1997).

Phenology: June-August (Spackman et al. 1997).

[+] Herbarium Photos

Images of Cirsium ownbeyi housed at the Colorado State University Herbarium.

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Click image to enlarge.

[+] Habitat

Habitat of Cirsium ownbeyi by Delia Malone.
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Habitat of Cirsium ownbeyi by Delia Malone.
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In Colorado, this species is found in pinyon-juniper, sagebrush, and riparian communities in open places in rocky, sandy, or clay soils. Found on gravelly alluvium, talus, or sandy slopes; usually on sandstone and occasionally on limestone of the Weber and Morgan formations. Often associated with alcove seeps and abandoned channels (Spackman et al. 1997, Ackerfield 2015). Associated taxa include Zigadenus vaginatusLimnorchis zothecinaAquilegia micrantha, Erigeron wilkenii, Fendlerella utahensis, Petrophyton caespitosum. Ephedra viridis, Heterotheca villosa, Cercocarpus montanusDodecatheon pulchellum, Clematis ligusticifoliaCarex lanuginosaChrysothamnus viscidiflorus, Rhus trilobata, Acer negundo, Senecio integerrimus, Cryptantha flava, Cirsium tracyi, Hymenopappus filifolius, Amelanchier utahensis, Mahonia repens, Stenotus acaulis, Tetraneuris acaulis, Pellaea glabella, Chrysothamnus nauseosus, Castilleja chromosaFraxinus anomala, and Pseudoroegneria spicata

Elevation Range: 5,079 - 7,398 feet (1,548 - 2,255 meters)

[+] Distribution

Distribution of Cirsium ownbeyi in Colorado according to mapped land ownership/management boundaries (CNHP 2017, COMaP).
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Distribution of Cirsium ownbeyi in Colorado.
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Colorado endemic: No
Global range: Cirsium ownbeyi is a regional endemic of northeast Utah, southwest Wyoming, and northwest Colorado.
State range: In Colorado, only in Moffat County.  Also known from a limited distribution in Utah and Wyoming.

[+] Threats and Management Issues

Habitat is generally inaccessible. However, this species could be mistaken for a non-native thistle and subject to weed treatments including inadvertent effects from biocontrol measures targeting other thistle species. Many occurrecnes are in Dinosaur National Park. Colorado climate scenarios for 2050 suggest temperature will increase by 3-7 F and precipitation may decrease or increase. The impact to any given rare plant habitat is likely to vary. Long-term monitoring that includes weather and soil moisture data is critical to understanding climate impacts.

[+] References

    • Ackerfield, J. 2015. Flora of Colorado. Brit Press, Botanical Research Institute of Texas, Fort Worth, TX. 818 pp.
    • Colorado Native Plant Society. 1989. Rare plants of Colorado. Rocky Mountain Nature Association, Colorado Native Plant Society, Estes Park, Colorado. 73 pp.
    • Colorado Natural Heritage Program and the Geospatial Centroid. 2017. The Colorado Ownership and Protection Map (COMaP). Colorado State University, Ft. Collins, CO.
    • Cronquist, A., A. H. Holmgren, N. H. Holmgren, J. L. Reveal, P. K. Holmgren. 1994. Intermountain Flora Vascular Plants of the Intermountain West, USA: Vol. 5. New York Botanical Garden, Bronx, NY.
    • Fletcher, R., B. Isaacs, P. Knight, W. Martin, D. Sabo, R. Spellenberg, and T. Todsen. 1984. A Handbook of Rare and Endemic Plants of New Mexico. University of New Mexico Press, Alburquerque, NM.
    • Flora of North America Editorial Committee. 2006. Flora of North America North of Mexico. Vol. 19. Magnoliophyta: Asteridae, part 6: Asteraceae, part 1. Oxford University Press, New York. xxiv + 579 pp.
    • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
    • O'Kane, S. L. 1988. Colorado's Rare Flora. Great Basin Naturalist. 48(4):434-484.
    • O'Kane, S.L. 1986. Plant species of special concern for the State of Colorado. Unpublished report.
    • Spackman, S., B. Jennings, J. Coles, C. Dawson, M. Minton, A. Kratz, and C. Spurrier. 1997. Colorado rare plant field guide. Prepared for Bureau of Land Management, U.S. Forest Service and U.S. Fish and Wildlife Service by Colorado Natural Heritage Program.
    • USDA, Natural Resources Conservation Service, PLANTS Database [USDA PLANTS]. Accessed 2017.
    • Weber, W. A. and R. C. Wittmann. 2012. Colorado Flora, Western Slope, A Field Guide to the Vascular Plants, Fourth Edition. Boulder, Colorado. 532 pp.
    • Welsh, S.L. 1982. New taxa of thistles (Cirsium, Asteraceae) in Utah. Great Basin Naturalist. 42:199-202.
    • Welsh, S.L., N.D. Atwood, L.C. Higgins and S. Goodrich. 1987. Utah Flora, Great Basin Naturalist Memoirs, No. 9. Brigham Young University, Provo, Utah. 986 pp.
    • Welsh, S.L., N.D. Atwood, S. Goodrich, and L.C. Higgins (eds.) 1993. A Utah flora. 2nd edition. Brigham Young Univ., Provo, Utah. 986 pp.

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