''Swainsona affinis'', commonly known as common poison pea, is a species of flowering plant in the family

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

and is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to arid areas of inland Australia. It is a prostrate

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

herb Herbs are a widely distributed and widespread group of plants, excluding vegetables, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal purposes, or for fragrances. Culinary use typically distingu ...

with

imparipinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and in ...

leaves with 7 to 25 broadly elliptic leaflets, and

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 ...

s of purple, pink, yellow or white flowers.

Description

''Swainsona affinis'' is a prostrate perennial herb, that typically grows to a height of up to and has softly-hairy stems. The leaves are imparipinnate, long with 7 to 25 broadly elliptic leaflets, the leaflets long and wide. The flowers are arranged in racemes long of 5 to 35 or more on a peduncle long, each flower long. The

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 are joined at the base, forming a tube with lobes shorter than the sepal tube. The petals are purple, pink, yellow or white. Flowering occurs from June to August, and the fruit is a broadly oblong, oval or spherical pod long with the remains of the

style Style, or styles may refer to: Film and television * ''Style'' (2001 film), a Hindi film starring Sharman Joshi, Riya Sen, Sahil Khan and Shilpi Mudgal * ''Style'' (2002 film), a Tamil drama film * ''Style'' (2004 film), a Burmese film * '' ...

wide.

Taxonomy and naming

This species was first formally described in 1948 by

Alma Theodora Lee Alma Theodora Lee (née Melvaine; 12 April 1912 — 20 October 1990) was an Australian botanist and plant taxonomist who worked at the National Herbarium of New South Wales, University of Sydney, and CSIRO. She is notable for raising the standar ...

who gave it the name ''Swainsona microphylla'' subsp. ''affinis'' in ''Contributions from the New South Wales National Herbarium''. In 1990

Joy Thompson Joy Thompson (born Joy Gardiner-Garden, 1923, died 2018) was an Australian botanist. Her main research areas were taxonomy and Myrtaceae. Life and career Thompson's university studies occurred during the second world war and in university vacat ...

raised it to species status as ''S. affinis'' in the journal '' Telopea''. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

(''affinis'') means "allied to" (a closely related species).

Distribution and habitat

''Swainsona affinis'' grows in red sand or sandy loam on the edges of salt lakes, in claypans, on sand dunes or along creek lines, often with mulga and ''

Callitris ''Callitris'' is a genus of coniferous trees in the Cupressaceae (cypress family). There are 16 recognized species in the genus, of which 13 are native to Australia and the other three (''C. neocaledonica, C. sulcata'' and ''C. p ...

'' species. It is widespread in the arid inland areas of Western Australia and South Australia, the south of the Northern Territory, in Queensland and west of

Narrabri Narrabri ( ) is a locality and seat of Narrabri Shire Local government in Australia, local government area in the North West Slopes, New South Wales, Australia on the Namoi River, northwest of Sydney. It sits on the junction of the Kamilaroi Hi ...

in New South Wales.

References

{{Taxonbar, from=Q63171065 affinis Fabales of Australia Flora of Western Australia Flora of the Northern Territory Flora of South Australia Flora of New South Wales Flora of Queensland Plants described in 1948