Shrubby Reed-mustard
Hesperidanthus suffrutescens
NatureServe conservation status
Global (G-rank): G1
State (S-rank): S1
Utah Wildlife Action Plan status
- SGCN
External links
General information
Hesperidanthus suffrutescens, is a federally listed as endangered species that occurs in mixed desert shrub communities, shale barrens, decomposed chip-rock, and limy shale in the Green River formation and the Uintah Basin of Duchesne County and Uintah County, Utah. This rare mustard has four petaled yellow flowers and is the only Hesperidanthus species with yellow flowers. Named for its many stemmed growth habit, Shrubby Reed-mustard has a remarkably distinct appearance where it grows.
Description
Hesperidanthus suffrutescens, is a federally listed as endangered species that occurs in mixed desert shrub communities, shale barrens, decomposed chip-rock, and limy shale in the Green River formation and the Uintah Basin of Duchesne County and Uintah County, Utah. This rare mustard has four petaled yellow flowers and is the only Hesperidanthus species with yellow flowers. Named for its many stemmed growth habit, Shrubby Reed-mustard has a remarkably distinct appearance where it grows.
Phenology
Flowers from May through July.
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. suffrutescens keys out very first within this small group from couplets addressing floral and leaf characteristics. Shrubby Reed-Mustard is distinct and rare for its yellow flowers and can be further identified by its shrubby growth habit of several stems and petioled leaves with their oblolanceolate to lanceolate or elliptic blade shape.
Hesperidanthus suffrutescens may be confused with Sisymbrium linifolia, but is distinguishable by its clump-forming growth habit.
Species range
Endemic to the Green River Formation, Uinta Basin of eastern Utah.
Threats or limiting factors
The inheriently small distribution (Uinta Basin area of Utah) and population size (estimated to be a little more than 3,000 individuals) of shrubby reed-mustard may increase the species’ vulnerability to threats (USFWS 2019). Threatened by habitat destruction associated with energy exploration and development, building stone collection, mining, off-road vehicle use, and grazing (Holmgren et al. 2005). The Uinta Basin is an area of intense oil and gas exploration; the development of both tar sands and oil shale are of interest (Franklin 2005). Observations in Utah Rare Plant Database report threats from feral horses (URPD, 2025).
Taxonomy
No, this species does not have taxonomic discrepancies