CPC Plant Profile: Ownbey's Thistle
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Plant Profile

Ownbey's Thistle (Cirsium ownbeyi)

Full view of flowering plant in native habitat. Note the finely divided lobes of the leaves. Photo Credit: Carol Dawson
Description
  • Global Rank: G3 - Vulnerable
  • Legal Status: N/A
  • Family: Asteraceae
  • State: CO, UT, WY
  • Nature Serve ID: 149014
  • Date Inducted in National Collection: 02/25/1988

Ownbey's thistle is the rarest native thistle in Colorado. First discovered in the state in 1987, it is found in the dry canyons and cliff walls of northwestern Colorado and northeastern Utah. Current research is attempting to determine the effect of an introduced biocontrol agent (Rhinocyllus conicus) on the seed production of the plant. This thistle is incredibly spiny and has white to rose colored flowers. The spines may help to protect the plant from water loss or grazing. The plant is found on lands managed by the Bureau of Land Management and National Park Service (Dinosaur National Monument). (Von Bargen 1997)

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Updates
  • 09/07/2020
  • Propagation Research

The Denver Botanic Gardens has been sampling populations of C. ownbeyi at Cross Mountain Canyon, Colorado, to determine the effect of the introduced biocontrol on seed production of this native thistle.

Nature Serve Biotics
  • 05/02/2017

Cirsium ownbeyi occurs across a very restricted range as a regional endemic to Colorado, Utah, and Wyoming. It is known from nearly 30 extant occurrences, with over 25,000 individuals, many on habitat that is somewhat self-protected. However, increased visitor use at the Dinosaur National Monument, where it occurs, poses a threat. The plant does seem to be adapted to natural surface disturbances.

Thomas Grant
  • 01/01/2010

Visitor traffic at Dinosaur National Monument and seed predation by Rhinocyllus conicus, a seed-eating weevil. This insect has been introduced across the intermountain western United States to help control Musk Thistle, a non-native noxious weed (Atwood

Thomas Grant
  • 01/01/2010

Remaining individuals are unknown.

Thomas Grant
  • 01/01/2010

The Denver Botanic Gardens has been sampling populations of C. ownbeyi at Cross Mountain Canyon, Colorado, to determine the effect of the introduced biocontrol on seed production of this native thistle.

Thomas Grant
  • 01/01/2010

Management strategies may have to account for the influence of the biocontrol agent.

Thomas Grant
  • 01/01/2010

Insect exclusion techniques need to be tested, especially if the biocontrol is shown to have a negative effect on seed production.

Thomas Grant
  • 01/01/2010

Seed collection, banking, germination, and growth protocols need to be established.

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Photos
Nomenclature
Taxon Cirsium ownbeyi
Authority Welsh
Family Asteraceae
CPC Number 961
ITIS 501549
USDA CIOW
Common Names Ownbey's thistle
Associated Scientific Names Cirsium ownbeyi
Distribution Endemic to the east flank of the Uinta Mountains in Daggett and northern Uintah counties, Utah; Sweetwater Co. in SW Wyoming, and Moffat County in NW Colorado. (Atwood et al. 1991)
State Rank
State State Rank
Colorado S2
Utah S1
Wyoming S2
Habitat

Sparsely vegetated juniper, sagebrush, and riparian communities. 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 stream channels. Elev. 5500-6200 ft. (Spackman 1997)

Ecological Relationships

Ecological relationships are unknown.

Pollinators
Common Name Name in Text Association Type Source InteractionID
Bees
Bees Confirmed Pollinator Link
Butterflies & Moths
Butterflies Confirmed Pollinator Link
Other
Wasps Confirmed Pollinator Link
Reintroduction
Lead Institution State Reintroduction Type Year of First Outplanting

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