''Acacia pterocaulon'' is a shrub belonging to the genus ''

Acacia ''Acacia'', commonly known as the wattles or acacias, is a large genus of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa and Australasia. The genus na ...

'' and subgenus ''Alatae''. It is native to a small area in the

Mid West The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of the United States. I ...

region of

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

Description

The intricate shrub has an erect or sprawling habit with many branches. It typically grows to a height of but can reach up to around . It has green glabrous branchlets. The

phyllode Phyllodes are modified petioles or leaf stems, which are leaf-like in appearance and function. In some plants, these become flattened and widened, while the leaf itself becomes reduced or vanishes altogether. Thus the phyllode comes to serve the ...

s are continuous with the branchlets, splitting to form opposing wings along the branchlet with each one extending to the next underneath. Each wing is wide. The free portion of each phyllode has a lanceolate to narrowly triangular shape and is straight or very shallowly incurved with a length of . It blooms between October and January producing yellow flowers. Each racemose

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 ...

s has globular head of a diameter containing 60 to 70 densely packed golden flowers. Linear

seed pod This page provides a glossary of plant morphology. Botanists and other biologists who study plant morphology use a number of different terms to classify and identify plant organs and parts that can be observed using no more than a handheld magnify ...

s form later that are up to in length and wide. Each oblong seed is long.

Taxonomy

The species was first formally described by the botanist

Bruce Maslin Bruce Roger Maslin (born 3 May 1946) is an Australian botanist, known for his work on ''Acacia'' taxonomy. Born in Bridgetown, Western Australia, he obtained an honours degree in botany from the University of Western Australia in 1967, then to ...

in 1995 as part of the work ''Acacia Miscellany 13. Taxonomy of some Western Australian phyllocladinous and aphyllodinous taxa (Leguminosae: Mimosoideae)'' as published in the journal ''

Nuytsia ''Nuytsia floribunda'' is a hemiparasitic tree found in Western Australia. The species is known locally as moodjar and, more recently, the Christmas tree or Western Australian Christmas tree. The display of intensely bright flowers during the ...

''. It was reclassified by

Leslie Pedley Leslie Pedley (19 May 1930 – 27 November 2018)IPNILeslie Pedley/ref> was an Australian botanist who specialised in the genus ''Acacia''. He is notable for bringing into use the generic name ''Racosperma'', creating a split in the genus, which r ...

in 2003 and ''Racosperma pterocaulon'' then transferred back to the current genus in 2006. The type specimen was collected by Maslin in 1976 near Three Springs. ''

Acacia willdenowiana ''Acacia willdenowiana'' is a shrub belonging to the genus ''Acacia''. The plant is also commonly known as wattle grass, grass wattle or two-winged acacia. It is native to the south west of Western Australia. Description The shrub has erect and ...

'' has phyllodes resembling those of ''A. pterocaulon''. It is also similar to the closely related ''

Acacia glaucoptera ''Acacia glaucoptera'', commonly known as flat wattle or clay wattle, is a species of ''Acacia'' which is endemic to the south-west of Western Australia. Description It is a spreading or erect shrub which ranges in height from and up to in wid ...

''.

Distribution

The species is confined to a small area between Morawa and Three Springs where it is found on rocky hill slopes where growing in clay-loam or sandy-loam soils. It is often part of the understorey in ''

Eucalyptus ''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including '' Corymbia'', they are commonly known as euca ...

'' woodland communities or in dense ''

Casuarina ''Casuarina'' is a genus of 17 tree species in the family Casuarinaceae, native to Australia, the Indian subcontinent, southeast Asia, islands of the western Pacific Ocean, and eastern Africa. It was once treated as the sole genus in the fami ...

'' scrub.

References

{{Taxonbar, from=Q15288577

pterocaulon ''Pterocaulon'' is a genus of flowering plants in the sunflower family, native to North and South America and to Australasia. Blackroot is a common name for species native to North America. The plants are perennial herbs, frequently densely cov ...

Acacias of Western Australia Plants described in 1995 Taxa named by Bruce Maslin

Description

Taxonomy

Distribution

See also

References