''Acacia leeuweniana'', also commonly known as Leeuwen's wattle or Spear Hill wattle,
is a tree 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 the subgenus ''Juliflorae'' that 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 north western
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
.
Description
The narrow and obconic tree typically grows to a height of . It has mini richi bark and inflorescence in spikes.
[ It usually has a single trunk or sometimes few trunks at the base of the tree. The brownish to red coloured bark exfoliates in narrow curled shavings that age to a grey colour. The terete, brittle branchlets have obscure ribbing. The green to grey-green ]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 mostly linear in shape and have a length of and a width of and have very fine parallel longitudinal nerves that are close together.[ It is known to flower between April and May and as late as October and is thought to bloom in response rainfall events. The simple ]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 occur in groups of two to six on the axil
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...
s. The flower-spikes have a length of with light golden flowers. The light grey-brown sub-woody 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 that form after flowering have a broad-linear shape and a length of and a width of . The pods are shallowly curved, glabrous and resinous with a visible marginal nerve. The shiny brown seeds are arranged longitudinally and have an
obloid to ellipsoidal shape. The flattened seeds have a length of and a width of large.[
]
Taxonomy
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 ...
honours Stephen van Leeuwen, who was a Scientist who made a large contribution to the understanding of the flora in the Pilbara. The tree is closely related to ''Acacia cyperophylla
''Acacia cyperophylla'', commonly known as creekline miniritchie or red mulga, is a tree in the family Fabaceae. The species' range extends across arid and semi-arid regions of Central Australia, from Carnarvon in Western Australia to western Q ...
''.[
]
Distribution
It is native to a small area in the Pilbara
The Pilbara () is a large, dry, thinly populated region in the north of Western Australia. It is known for its Aboriginal peoples; its ancient landscapes; the red earth; and its vast mineral deposits, in particular iron ore. It is also a glo ...
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 ...
where it is found amongst boulders in rocky outcrops growing in fissures in skeletal sandy loam to gravelly sand soils over and around granite
Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...
.
See also
* List of ''Acacia'' species
References
{{Taxonbar, from=Q17438705
leeuweniana
Acacias of Western Australia
Plants described in 2008
Taxa named by Bruce Maslin