''Peteria thompsoniae'' is a species of flowering plant in the legume family known by the common names spine-noded milkvetch and Thompson's peteria. It is native to the western United States, where it grows in salt desert shrublands in soils of

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, created during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to refer ...

origin, and in

alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to semiarid climates, but a ...

s. It is a spiny perennial herb growing from a

taproot A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproo ...

and rhizome system, its stem growing 20 to 60 centimeters tall. The leaves are made up of several pairs of oval leaflets. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...

, a spikelike raceme at the top of the stem, produces white or pinkish pealike flowers up to 2.5 centimeters long, its base encapsulated in a tubular calyx of glandular

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coine ...

s. The fruit is a leathery, slightly inflated legume pod up to 6 centimeters long.

History

''Peteria thompsoniae'' was published as a new species by

Sereno Watson Sereno Watson (December 1, 1826 in East Windsor Hill, Connecticut – March 9, 1892 in Cambridge, Massachusetts) was an American botanist. Graduating from Yale in 1847 in Biology, he drifted through various occupations until, in California, he j ...

in 1873, based on material collected by

Ellen Powell Thompson Ellen Louella (Nellie) Powell Thompson (1840–1911) was an American naturalist and botanist, and an active advocate for women's suffrage. Life Ellen Louella (Nellie) Powell Thompson was born in Ohio to parents of English origin. Her siblings i ...

in 1872 in the vicinity of Kanab, Utah, during the US Topographical and Geological Survey of the Colorado River (led by

John Wesley Powell John Wesley Powell (March 24, 1834 – September 23, 1902) was an American geologist, U.S. Army soldier, explorer of the American West, professor at Illinois Wesleyan University, and director of major scientific and cultural institutions. He ...

). Her specimen, the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

, is deposited at the Gray Herbarium.Digital record and specimen imag
Gray Herbarium

References

External links

Jepson Manual TreatmentUSDA Plants Profile
Robinieae {{Faboideae-stub