Stanleya, commonly known as prince's plumes, is a genus of flowering plants in the family Brassicaceae (order Brassicales), native to the western and central United States and northern Mexico. The genus comprises approximately seven accepted species ranging from annuals to perennials and subshrubs, often with a woody base.
Plants are typically erect, reaching shrub-like proportions in some species, and bear striking, plumelike racemes that elongate considerably in fruit — a feature responsible for the common name. The flowers are most often bright yellow, though white and yellow-orange forms occur; petals have a distinctly differentiated claw, and the six stamens are markedly exserted with linear anthers that coil spirally after dehiscence. The fruits are long-stipitate, narrow, and often torulose (beaded), with seeds arranged in a single row.
Stanleya is best known ecologically as a selenium hyperaccumulator: the plants concentrate selenium from seleniferous soils to levels toxic to livestock and other animals, making several species important indicator plants for selenium-rich geology in arid western landscapes. The most widespread member, Stanleya pinnata (desert prince's plume), is frequently encountered on selenium-bearing shales and gypseous desert soils of the Intermountain West.
Etymology
The genus name Stanleya honors Edward Smith-Stanley (1775–1851), the 13th Earl of Derby, a prominent British statesman and naturalist who served as president of the Linnean Society and was a noted patron of natural history.
Distribution
Stanleya species are native to the western and central United States and northern Mexico, growing primarily on arid and semi-arid terrain. The genus reaches its greatest diversity in the Intermountain West, with individual species occupying ranges from the Columbia Plateau (S. confertiflora) south to the Sonoran and Mojave deserts (S. pinnata, S. elata).
Ecology
Stanleya species are obligate or facultative selenium hyperaccumulators, drawing selenium from seleniferous soils — primarily derived from Cretaceous marine shales — and concentrating it in their tissues to levels acutely toxic to livestock. This trait makes them reliable geobotanical indicators of selenium-rich substrates. The plants occupy dry, open habitats including desert shrublands, rocky slopes, and sandy washes.
