''Sphaerophysa salsula'' is a species of flowering plant in the
known by the common names alkali swainsonpea, Austrian peaweed, and red bladder-vetch. It is native to Asia but it is known in many other parts of the world as an
introduced species
An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...
and often a
noxious weed
A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or liv ...
. It grows in cultivated land and disturbed habitat, easily tolerating
alkaline
In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a base (chemistry), basic, ionic compound, ionic salt (chemistry), salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as ...
substrates. It is commonly seen in areas where
alfalfa
Alfalfa () (''Medicago sativa''), also called lucerne, is a perennial flowering plant in the legume family Fabaceae. It is cultivated as an important forage crop in many countries around the world. It is used for grazing, hay, and silage, as w ...
is grown, because the seeds of the two species look similar and the weed seed is easily imported with the crop seed.
This is a long-lived perennial herb growing up to 1.5 meters tall. It reproduces via seed as well as by sprouting vigorously from its creeping root system. The stems are coated in short white hairs. The leaves are made up of many oval leaflets each up to two centimeters long. The
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. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...
is a
raceme
A raceme ( or ) or racemoid is an unbranched, 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 produced as the s ...
of several pea-like flowers each just over a centimeter wide. They may be brick-red to deep pink to brownish or red-orange in color. The fruit is a
legume
A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...
pod up to 3.5 centimeters long. It is inflated and bladderlike, hairless, translucent, shiny, and papery when dry. It is mottled greenish or reddish. It contains several seeds each about two millimeters long.
Like other legumes, this plant contains
endophytes. These include the
bacterium
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
''
Paracoccus sphaerophysae'', which was recently isolated from the roots of this species, and named for it. Other
rhizobia
Rhizobia are diazotrophic bacteria that fix nitrogen after becoming established inside the root nodules of legumes (Fabaceae). To express genes for nitrogen fixation, rhizobia require a plant host; they cannot independently fix nitrogen. In gene ...
in this species include ''
Shinella kummerowiae'' and species of the genera ''
Rhizobium
''Rhizobium'' is a genus of Gram-negative soil bacteria that fix nitrogen. ''Rhizobium'' species form an endosymbiotic nitrogen-fixing association with roots of (primarily) legumes and other flowering plants.
The bacteria colonize plant cells ...
'', ''
Agrobacterium
''Agrobacterium'' is a genus of Gram-negative bacteria established by H. J. Conn that uses horizontal gene transfer to cause tumors in plants. ''Agrobacterium tumefaciens'' is the most commonly studied species in this genus. ''Agrobacterium'' is ...
'', and ''
Mesorhizobium
''Mesorhizobium'' is a genus of Gram-negative soil bacteria. At least one, the nitrogen fixing species, ''Mesorhizobium loti'', forms symbiotic root nodules with plants in the genus '' Lotus''. Strain MAFF303099 of ''M. japonicum'' has been full ...
''.
[Xu, L., et al. (2008). Genetic diversity in rhizobia isolated from ''Sphaerophysa salsula'' in several regions of northwestern China. ''Acta Entomologica Sinica'' 51:5 1017-98.]
References
External links
Jepson Manual TreatmentUSDA Plants ProfileWashington Burke MuseumPhoto gallery
Galegeae
{{Faboideae-stub