''Peteria thompsoniae'' is a species of flowering plant in the family

Fabaceae Fabaceae () or Leguminosae,International Code of Nomen ...

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, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...

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 Semi-arid climate, semiar ...

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 taproot ...

and

rhizome In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...

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

, a spikelike

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 ...

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 Etymology The term ''sepalum'' ...

s. The fruit is a leathery, slightly inflated

legume Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consum ...

pod up to 6 centimeters long.

History

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

Sereno Watson Sereno Watson (December 1, 1826 – March 9, 1892) was an American botanist. Life Watson was born on December 1, 1826, in East Windsor Hill, Connecticut. Graduating from Yale in 1847 in biology, he drifted through various occupations unt ...

in 1873, based on material collected by Ellen Powell Thompson 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 (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

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

References

External links

Jepson Manual TreatmentUSDA Plants Profile
Robinieae {{Faboideae-stub