CPC Plant Profile: Syes Butte Plains-mustard
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Plant Profile

Syes Butte Plains-mustard (Hesperidanthus barneybi)

This shot shows the entire plant, including flowers. Photo Credit: ©R. Delmatier
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Brassicaceae
  • State: UT
  • Nature Serve ID: 131256
  • Date Inducted in National Collection: 12/01/2021

This species was listed as Federally Endangered in 1992, and since that time the number of plants in the two remaining populations has increased from approximately 1,000 plants to a little over 2,000 plants (USFWS 1992; Clark and Groebner 2000). Barneby's reed mustard is a perennial herbaceous plant found only in south-central Utah. Plants are 10-25 cm tall with smooth stems. Flowers are produces from late April to mid-June, produces on racemes that contain 2-28 flowers each. The sepals of these flowers are green to violet, with papery margins. The flowers themselves are whit to lavender, with conspicuous purplish veins. This species is in the Brassicaceae family, and it produces seed pods called siliques. (Clark and Groebner 2000)

Participating Institutions
Nature Serve Biotics
  • 05/02/2017

Endemic to the Canyonlands of south-central Utah, where known from five occurrences in two distinct clusters: one in the southern portion of the San Rafael Swell in southern Emery County (administered by the BLM) and the other in Capitol Reef National Park in central Wayne County. Approximately 3,000 plants are known, but this may be an underestimate since this species occurs on difficult terrain. The Emery County occurrences are threatened by habitat degradation associated with uranium mining claim annual assessment work (an access road bisects the population); degradation could become more severe in the future if abandoned uranium mines near these occurrences were ever reopened. The Wayne County occurrences are vulnerable to trampling by hikers.

Sylvia Torti
  • 01/01/2010

Potential uranium mining activity Recreational development Foot traffic from visitors to Capitol Reef National Park (USFWS 1994)

Sylvia Torti
  • 01/01/2010

Only two known populations known, totaling approximately 2000 individuals. (Clark and Groebner 2000)

Sylvia Torti
  • 01/01/2010


Sylvia Torti
  • 01/01/2010

Currently managed by the BLM and Park Service at Capitol Reef National Park.

Sylvia Torti
  • 01/01/2010

This plant has not yet been germinated from seed. Tissue culture might be tried.


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Taxon Hesperidanthus barneybi
Authority (S.L. Welsh & N.D. Atwood) Al-Shehbaz
Family Brassicaceae
CPC Number 3871
ITIS 823219
Common Names Barneby reed-mustard | Barneby thelypody | Sye's Butte plainsmustard | Syes Butte plainsmustard
Associated Scientific Names Schoenocrambe barnebyi | ​Hesperidanthus barnebyi | Thelypodiopsis barnebyi
Distribution Known only from two populations in central Utah, one in Capitol Reef National Park and the other the San Rafael Swell. (USFWS 1992)
State Rank
State State Rank
Utah S1

This species grows on red clay soils rich in selenium and gypsum, overlain with sandstone talus at elevations between 1646-1753 meters. Populations are found on steep slopes, generally on northern exposures. Associated plant species are sagebrush, rabbitbush and Ephedra. (USFWS 1992)

Ecological Relationships


Common Name Name in Text Association Type Source InteractionID

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