Peteria thompsoniae
Encyclopedia
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
origin, and in alluvial fan
s. It is a spiny perennial herb growing from a taproot
and rhizome
system, its stem growing 20 to 60 centimeters tall. The leaves are made up of several pairs of oval leaflets. The inflorescence
, 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
s. The fruit is a leathery, slightly inflated legume pod up to 6 centimeters long.
Fabaceae
The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species...
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
Volcanic ash consists of small tephra, which are bits of pulverized rock and glass created by volcanic eruptions, less than in diameter. There are three mechanisms of volcanic ash formation: gas release under decompression causing magmatic eruptions; thermal contraction from chilling on contact...
origin, and in alluvial fan
Alluvial fan
An alluvial fan is a fan-shaped deposit formed where a fast flowing stream flattens, slows, and spreads typically at the exit of a canyon onto a flatter plain. A convergence of neighboring alluvial fans into a single apron of deposits against a slope is called a bajada, or compound alluvial...
s. It is a spiny perennial herb growing from a taproot
Taproot
A taproot is an enlarged, somewhat straight to tapering plant root that grows vertically downward. It forms a center from which other roots sprout laterally.Plants with taproots are difficult to transplant...
and rhizome
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
system, its stem growing 20 to 60 centimeters tall. The leaves are made up of several pairs of oval leaflets. The inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
, a spikelike raceme
Raceme
A raceme is a type of inflorescence that is unbranched and indeterminate and bears pedicellate flowers — flowers having short floral stalks called pedicels — along the axis. In botany, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne...
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
Sepal
A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...
s. The fruit is a leathery, slightly inflated legume pod up to 6 centimeters long.