''Acacia rigescens'' 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 the subgenus ''Juliflorae'' that is native to northern
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 single stemmed shrub typically grows to a maximum height of and has a spindly, viscid habit. It has grey coloured bark that is smooth and
glabrous, scurfy angular branchlets that are a pale-yellow to tawny colour. Like most species of ''Acacia'' it has
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 rather than true leaves. The glossy green, coriaceous and glabrous phyllodes are held rigidly erect on the branchlets. The straight and flat phyllodes have a linear shape that tapers gradually towards the base but barely taper near the apex, they have a length of and a width of and a prominent midvein. It blooms between June and July producing golden flowers. The cylindrical flower-spikes occur singly or in pairs and have a length of and are packed with golden coloured flowers.
Taxonomy
The species was first formally described in 1996 by the botanists
Mary Tindale
Mary Douglas Tindale (19 September 1920 – 31 March 2011) was an Australian botanist specialising in pteridology (ferns) and the genera ''Acacia'' and ''Glycine''.
Tindale was born in Randwick, New South Wales, the only child of George Harold Ti ...
and Michael Bedward as part of the work ''Acacia multistipulosa and A. rigescens (Fabaceae: Mimosoideae, Acacia sect. Juliflorae), two new species from the
Northern Territory, Australia as published in the journal ''
Australian Systematic Botany''. It was reclassified as ''Racosperma rigescens'' by
Leslie Pedley in 2003 then transferred back to the ''Acacia'' genus in 2006.
Distribution
It is
endemic to a small area in the
top end of the
Northern Territory in the
Kakadu National Park and parts of
Arnhem Land
Arnhem Land is a historical region of the Northern Territory of Australia, with the term still in use. It is located in the north-eastern corner of the territory and is around from the territory capital, Darwin. In 1623, Dutch East India Compan ...
where it is Kakadu Natl Park and Arnhem Land on sandstone plateaux that have a stony quartz surfaces where it grows in a range of soil types as a part of low open ''
Eucalyptus'' woodland and shrubland communities.
[
]
See also
* List of ''Acacia'' species
References
{{Taxonbar, from=Q15288731
rigescens
Flora of the Northern Territory
Plants described in 1996