Barneby's Reed-Mustard
Hesperidanthus barnebyi
Other common names: Sye's Butte Plainsmustard
NatureServe conservation status
Global (G-rank): G2
State (S-rank): S2
Utah Wildlife Action Plan status
- SGCN
External links
General information
Hesperidanthus barnebyi, is a Federally listed as endangered plant that grows in desert communities on the Chinie Formation of the Colorado Plateau in Emery County and Wayne County, Utah. Barneby reed-mustard has distinct four petaled white to lilac flowers which grow at the top of long thin stems giving this rare species unique appearance in the dry region where it is found.
Description
Hesperidanthus barnebyi, is a Federally listed as endangered plant that grows in desert communities on the Chinie Formation of the Colorado Plateau in Emery County and Wayne County, Utah. Barneby reed-mustard has distinct four petaled white to lilac flowers which grow at the top of long thin stems giving this rare species unique appearance in the dry region where it is found.
Phenology
Flowers from late April to early June.
Diagnostic characteristics
Hesperidanthus is a small genus of flowering plants with only 5 species yet described in North America and 3 of these occur only in Utah. H. barnebyi keys out last within this small group from couplets addressing floral and leaf characteristics. Barneby Reed-Mustard is distinct and rare for its combination of purple, lilac, lavender flowers, linear anthers measuring 2.5-3 mm, and petioled leaves with their oblong or elliptic to oblanceolate shape.
Hesperidanthus barnebyi is a relatively distinct plant within its range. Vegetatively, Barneby Reed-Mustard can resemble Stanleya pinnata however, S. pinnata generally has larger leaves (5-18 cm long, 2-5 cm wide) relative to H. barnebyi (1.3-5.1 cm long, 0.4-2.4 cm wide).
Species range
Endemic to the Canyonlands of south-central Utah, known from two distinct clusters of occurrences: one in the southern portion of the San Rafael Swell near Muddy Creek in southern Emery County and the other in Capitol Reef National Park in the Fremont River drainage west of Fruita in central Wayne County.
Threats or limiting factors
The inheriently small distribution (Emery and Wayne counties, Utah) and population size (estimated to be less than 3,000 individuals) of Barneby reed-mustard is not a threat, but may increase the species’ vulnerability to threats (USFWS 2021). Historical mining likely impacted this species, but currently there are few pre-existing mining claims within occupied habitat (Anderson 2021, USFWS 2021). Climate change continues to have the potential to affect the species, but it is unclear the effect of these stressors on this species at this time (USFWS 2021). Recreation on NPS lands may be impacting some individuals that occur near a popular hiking trail (URPD, accessed 2025). Domestic grazing may have had an impact on this species historically, but is not believed to be a significant threat currently due to grazing management by the Federal agencies (USFWS 2011).
Taxonomy
No, this species does not have taxonomic discrepancies