''Thryptomene decussata'' is a species of flowering plant in the family

Myrtaceae Myrtaceae, the myrtle family, is a family of dicotyledonous plants placed within the order Myrtales. Myrtle, pōhutukawa, bay rum tree, clove, guava, acca (feijoa), allspice, and eucalyptus are some notable members of this group. All speci ...

and is

endemic Endemism is the state of a species being found 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 found elsew ...

to Western Australia. It is an erect shrub with upward pointing, egg-shaped leaves, and white or pink flowers with five petals and twenty to thirty

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s in two

whorls A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral d ...

Description

''Thryptomene decussata'' is an erect, open shrub that typically grows to a height of , often with large galls on the stems and flowers. Its leaves are pointed upwards and broadly egg-shaped with the narrower end towards the base, long and wide on a petiole long. The flowers are arranged in pairs in up to three adjacent leaf axils, on peduncles about long with bracteoles long that remain until the fruit falls. The flowers are in diameter and cup-shaped with egg-shaped, pinkish

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 coined b ...

s long and wide. The petals are pink, long and there are twenty to thirty stamens in two whorls, some with filaments up to long. Flowering occurs from May to November.

Taxonomy

This species was first formally described in 1904 by William Vincent Fitzgerald who gave it the name ''Scholtzia decussata'' in the '' Journal of the West Australian Natural History Society''. In 1985, John Green changed the name to ''Thryptomene decussata''. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

(''decussata'') refers to the

decussate Decussation is used in biological contexts to describe a crossing (due to the shape of the Roman numeral for ten, an uppercase 'X' (), ). In Latin anatomical terms, the form is used, e.g. . Similarly, the anatomical term chiasma is named aft ...

arrangement of the leaves.

Distribution and habitat

This thryptomene is widely distributed from near

Shark Bay Shark Bay (Malgana: ''Gathaagudu'', "two waters") is a World Heritage Site in the Gascoyne region of Western Australia. The http://www.environment.gov.au/heritage/places/world/shark-bay area is located approximately north of Perth, on the ...

to near Leonora, growing on sand plains, breakaways and on stony ridges in the Coolgardie,

Gascoyne The Gascoyne region is one of the nine administrative regions of Western Australia. It is located in the northwest of Western Australia, and consists of the local government areas of Carnarvon, Exmouth, Shark Bay and Upper Gascoyne. The Gasc ...

, Murchison and Yalgoo

biogeographic regions A biogeographic realm or ecozone is the broadest biogeographic division of Earth's land surface, based on distributional patterns of terrestrial organisms. They are subdivided into bioregions, which are further subdivided into ecoregions. De ...

Conservation status

''Thryptomene decussata'' is classified as "not threatened" by the Western Australian Government

Department of Parks and Wildlife The Department of Parks and Wildlife (DPaW) was the department of the Government of Western Australia responsible for managing lands described in the ''Conservation and Land Management Act 1984'' and implementing the state's conservation and e ...

References

{{Taxonbar, from=Q15388567 decussata Rosids of Western Australia Plants described in 1904 Taxa named by William Vincent Fitzgerald