''Lepidium barnebyanum'' is a rare species of flowering plant in the family

Brassicaceae Brassicaceae () or (the older but equally valid) Cruciferae () is a medium-sized and economically important Family (biology), family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous pla ...

known by the common names Barneby's pepperweed, Barneby's pepper-grass, and Barneby's ridge-cress. It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

, where there is a single population in

Duchesne County Duchesne County ( ) is a county in the northeast part of the U.S. state of Utah. As of the 2020 United States census, the population was 19,596. Its county seat is Duchesne, and the largest city is Roosevelt. History Much of Duchesne County ...

. It is a federally listed

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

of the United States. This is a clumpy perennial herb with a woody

caudex A caudex (: caudices) of a plant is a stem, but the term is also used to mean a rootstock and particularly a basal stem structure from which new growth arises.pages 456 and 695 In the strict sense of the term, meaning a stem, "caudex" is most ...

at the base layered with new leaves and the remains of previous seasons' leaves. The stems grow less than 20 centimeters tall. The leaves are linear in shape and one half centimeter to eight centimeters in length. Most are at the caudex and there are a few smaller ones higher on the stems. The

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

is a

raceme A raceme () or racemoid is an unbranched, indeterminate growth, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are ...

of many white, cream, or yellowish flowers.''Lepidium barnebyanum''.
Flora of North America. Blooming occurs in April and May''Lepidium barnebyanum''.
Center for Plant Conservation. through June. This plant grows in pinyon-juniper woodland and desert scrub on rock outcrops in white

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

formations.''Lepidium barnebyanum''.
The Nature Conservancy. There are

petroleum Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring un ...

deposits under the rock. Common plants in the area include

Colorado Pinyon ''Pinus edulis'', the Colorado pinyon, two-needle piñon, pinyon pine, or simply piñon, is a pine in the pinyon pine group native to the Southwestern United States, used for its edible pine nuts. Description The piñon pine (''Pinus edulis'' ...

(''Pinus edulis''),

Utah juniper ''Juniperus osteosperma'' (Utah juniper; syn. ''J. utahensis'') is a shrub or small tree native to the southwestern United States. Description The plant reaches , rarely to 9 m, tall. The shoots are fairly thick compared to most junipers, in ...

(''Juniperus osteosperma''), Hooker's sandwort (''Arenaria hookeri''), spiny phlox (''Phlox hoodii''), Colorado feverfew (''Parthenium ligulatum''), large-flowered goldenweed (''Haplopappus armerioides''), stemless hymenoxys (''Hymenoxys acaulis''), Bateman's buckwheat (''Eriogonum batemanii''), and table Townsend daisy (''Townsendia mensana''). There is one known population of this plant containing about 5000 individuals. The population occurs on a shale substrate that is popular with

off-road vehicle An off-road vehicle (ORV), also known as an off-highway vehicle (OHV), overland vehicle or adventure vehicle, is a type of transportation specifically engineered to navigate unpaved roads and surfaces. These include trails, forest roads, and ...

enthusiasts whose vehicles damage the habitat. Petroleum exploration is also a threat.

References

banebyanum Flora of Utah Duchesne County, Utah Plants described in 1967 {{Brassicales-stub