Clay Reed-mustard

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Clay Reed-mustard

Schoenocrambe argillacea

ListedJanuary 14, 1992
FamilyCruciferae (Brassicaceae)
DescriptionPerennial herb with sparsely leafed stems 6-12 in (15.2-30.5 cm) tall from a woody root crown.
HabitatDesert shrub on clay soils which are rich in gypsum and overlain with sandstone talus.
ThreatsSurface disruption associated with oil and gas development.


The clay reed-mustard is a perennial herb with sparsely leafed stems 6-12 in (15.2-30.5 cm) tall which rise from a woody root crown. The leaves are very narrow with smooth margins and grow to 0.4-1.4 in (1-3.6 cm) in length and less than 0.1 in (0.25 cm) in width. Leaves are alternately arranged on the stem and are attached directly without a petiole. Flowers range in color from pale lavender to whitish with purple veins. Petals measure from 0.3-0.4 in (0.8-1 cm) in length and from 0.14-0.18 in (0.36-0.46 cm) in width. The entire flowers are 0.4 in (1 cm) across in full anthesis and are displayed in clusters of from 3-20 at the end of the leafy stems. Flowering occurs in May to early June.


This species occurs in mixed desert shrub and shadscale communities between the elevations of 5,000-5,650 ft (1,524-1722 m). It grows on clay soils which are rich in gypsum and overlain with sandstone talus. The soils are derived from a mixture of shales and sandstones from the zone of contact between the Uinta and Green River geologic formation. The species is associated with Eriogonum carymbosum, Ephedra torreyana, Atriplex spp., and Artemisia spp.


Past distribution of this species is unknown. At present, the species occurs in only two populations in Uintah County, Utah. Both are Federally owned (Bureau of Land Management, Vernal District and Diamond Mountain Resource Area, and Utah Indian Tribal lands) and are subject to mineral leasing by the government. Clay reed-mustard may occur on Ute Indian Tribal lands.


The species is threatened by surface disruption associated with energy development within its habitat. All known populations occur on Federal lands that are leased for their oil and gas energy reserves. An increase in oil and gas exploratory activity could lead to further development. The entire habitat of the species is underlain by oil shale which may be mined when economic conditions favor it.

In the past, grazing has negatively impacted the species but no longer is a threat due to the management efforts of the Bureau of Land Management (BLM). Some sites do not support enough individuals to maintain genetic viability.

Conservation and Recovery

All populations of this species occur on lands administered by the BLM or the Ute Indian Tribal lands. The BLM is responsible for leasing mineral rights under the jurisdiction of the United States. It may not lease any rights which may cause harm to this species without first consulting with the U.S. Fish and Wildlife Service (FWS). In the meantime, specific recovery goals are being drafted by the FWS.

This species was listed as Endangered in part because of the potential of mineral development actions adversely impacting it. A threat to the clay reed-mustard is habitat destruction associated with potential uranium mining activity. Assessment work related to mining claims for uranium is a chronic threat to this mustard and its habitat. The BLM requires a mine plan be prepared for mining assessment areas within environmentally critical areas which must provide for the conservation of those environmental values.

Formal land management designations need to be established to provide habitat protection. Such designations may include the following: Research Natural Areas, Areas of Critical Environmental Concern, or designated Wilderness. Special protected areas similar to those mentioned above should ensure the long-term protection of enough populations of this mustard to ensure its survival as a vigorous reproducing species. The Center for Plant Conservation should consider inclusion of individual living specimens of this mustard in the "National Collection of Endangered Plant Species" and subsequently, propagation. These collections are for the purpose of maintaining a refuge garden population for those species which are threatened in their natural habitat and for conducting research beneficial to the species' conservation and recovery, including techniques necessary for the establishment of additional populations in suitable habitat.

Introduction of new stands into or proximal to the species' current range may be conducted if suitable habitat is found and if such introduction is determined to be desirable or feasible. Because no reintroductions have previously been undertaken, the success of such reintroductions is uncertain. Reintroductions, however, should be considered for the biological information that would be obtained and for the possibility of successful establishment of viable stands of the species.


U.S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
P. O. Box 25486
Denver Federal Center
Denver, Colorado 80225
Telephone: (303) 236-7920

Ecological Services Field Office
Lincoln Plaza
145 East 1300 South, Suite 404
Salt Lake City, Utah 84115
Telephone: (801) 524-5001


U.S. Fish and Wildlife Service. 14 January 1992. "Endangered and Threatened Wildlife and Plants; Final Rule to determine the Plant Schoenocrambe argillacea (Clay Reed-Mustard) To be a Threatened Species, and the Plant Schoenocrambe barnebyi (Barneby Reed-Mustard) To be an Endangered Species." Federal Register 57 (9): 1398-1402.