''Allocasuarina'' is a
genus of trees in the
flowering plant family
Casuarinaceae. They are
endemic to
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 ...
, occurring primarily in the south. Like the closely related genus ''
Casuarina'', they are commonly called sheoaks or she-oaks.
Wilson and Johnson
distinguish the two very closely related genera, ''
Casuarina'' and ''Allocasuarina'' on the basis of:
*''
Casuarina'': the mature samaras being grey or yellow-brown, and dull; cone bracteoles thinly woody, prominent, extending well beyond cone body, with no dorsal protuberance;
*''Allocasuarina'': the mature samaras being red-brown to black, and shiny; cone bracteoles thickly woody and convex, mostly extending only slightly beyond cone body, and usually with a separate angular, divided or spiny dorsal protuberance.
Description
They are trees or shrubs that are notable for their long, segmented branchlets that function as leaves. Formally termed
cladodes
:''In botany, "Cladodes" may refer to a synonym of the genus '' Alchornea'' or to the plural of " cladode".''
''Cladodes'' is a genus of firefly beetles.
It used to be included in the subfamily Amydetinae, which is probably a highly artifici ...
, these branchlets somewhat resemble
pine needles, although sheoaks are
flowering plants. The
leaves
A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...
are reduced to minute scales encircling each joint. Fallen cladodes form a dense, soft mat beneath sheoaks, preventing the development of undergrowth (a phenomenon known as
allelopathy
Allelopathy is a biological phenomenon by which an organism produces one or more biochemicals that influence the germination, growth, survival, and reproduction of other organisms. These biochemicals are known as allelochemicals and can have be ...
) and making sheoak woods remarkably quiet.
Another characteristic feature are the spiny "cones", about the size of an
acorn
The acorn, or oaknut, is the nut of the oaks and their close relatives (genera ''Quercus'' and '' Lithocarpus'', in the family Fagaceae). It usually contains one seed (occasionally
two seeds), enclosed in a tough, leathery shell, and borne ...
but with a texture more resembling a
conifer cone. However, sheoak "cones" are a woody
fruit.
As with
legume
A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...
s, sheoak roots possess nodules containing
symbiotic
Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...
nitrogen fixing
Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the Atmosphere of Earth, air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but al ...
bacteria; together with their highly
drought-adapted foliage, this enables sheoaks to thrive in very poor soil and semi-arid areas. However, sheoaks are much less
bushfire-tolerant than
eucalypts.
Fossils of closely related species have been found dating back to the time of
Gondwana
Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...
.
Uses
The hard wood and rich texture makes sheoak wood popular among
wood-turners. Sheoak wood is also regarded as an excellent
firewood
Firewood is any wooden material that is gathered and used for fuel. Generally, firewood is not highly processed and is in some sort of recognizable log or branch form, compared to other forms of wood fuel like pellets or chips. Firewood can ...
as it burns with very little ash.
Because of its ability to grow and develop extensive root systems in very poor or sandy soils, and to completely cover the ground with its "needles", it is often used to stabilise soils in
erosion prone areas, or on
sand dune
A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, fl ...
s. Sheoak is also used as an
ornamental shrub, although for this purpose the mat of "needles" may become a nuisance and must be carefully considered.
List of species
''Allocasuarina'' comprises the following species:
* ''
Allocasuarina acuaria
''Allocasuarina acuaria'' is a shrub of the genus ''Allocasuarina'' native to the Wheatbelt, Goldfields-Esperance and Great Southern regions of Western Australia.
The dioecious shrub typically grows to a height of . The cone is often obscured ...
''
* ''
Allocasuarina acutivalvis
''Allocasuarina acutivalvis'' is a shrub or tree of the genus ''Allocasuarina'' native to the Wheatbelt, Goldfields-Esperance and Mid West regions of Western Australia.
The dioecious shrub or tree typically grows to a height of . It produces b ...
''
* ''
Allocasuarina brachystachya
''Allocasuarina brachystachya'' is a species of flowering plant in the family Casuarinaceae and is endemic to the Northern Tablelands of New South Wales. It is an open, usually monoecious shrub that has branchlets up to long, the leaves reduced ...
''
* ''
Allocasuarina campestris
''Allocasuarina campestris'', commonly known as the Shrubby she-oak, is a shrub of the she-oak family Casuarinaceae native to Western Australia.
The dioecious or monoecious shrub typically grows to a height of and produces red-brown flowers fro ...
'' (tamma)
* ''
Allocasuarina corniculata
''Allocasuarina corniculata'' is a species of flowering plant in the family Casuarinaceae and is endemic to the south-west of Western Australia. It is an erect to spreading, dioecious shrub that has more or less erect branchlets, the leaves redu ...
''
* ''
Allocasuarina crassa
''Allocasuarina crassa'', commonly known as Cape Pillar sheoak, is a species of flowering plant in the family Casuarinaceae and is endemic to a small area in far south-eastern Tasmania. It is a low shrub to small tree that is monoecious or dioe ...
'' (Cape Pillar sheoak)
* ''
Allocasuarina decaisneana'' (Desert oak)
* ''
Allocasuarina decussata
''Allocasuarina decussata'', commonly known as karri oak or karri she-oak, is a medium-sized tree, or more rarely a shrub, that is endemic to the south west of Western Australia. It is an understory tree in karri forest but also occurs as a stun ...
'' (Karri oak)
* ''
Allocasuarina defungens
''Allocasuarina defungens'', commonly known as dwarf heath casuarina, is a species of flowering plant in the family Casuarinaceae and is endemic to a restricted area of New South Wales. It is a straggly, dioecious or monoecious shrub that has br ...
''
* ''
Allocasuarina dielsiana'' (Northern sheoak)
* ''
Allocasuarina diminuta
''Allocasuarina diminuta'' is a species of flowering plant in the family Casuarinaceae and is endemic to eastern New South Wales. It is a Dioecy, dioecious or Monoecy, monoecious shrub or small tree that has branchlets up to long, the leaves r ...
''
* ''
Allocasuarina distyla
''Allocasuarina distyla'', commonly known as scrub she-oak, is a shrub or small tree of the She-oak family Casuarinaceae endemic to New South Wales.
Description
This dioecious shrub or small tree will typically grow to a height of tall, or 7 me ...
'' (Scrub sheoak)
* ''
Allocasuarina drummondiana
''Allocasuarina drummondiana'' is a species of flowering plant in the family Casuarinaceae and is endemic to the south-west of Western Australia. It is an intricately branched, dioecious shrub that has its leaves reduced to scales in whorls of si ...
''
* ''
Allocasuarina duncanii'' (Duncan's sheoak)
* ''
Allocasuarina emuina
''Allocasuarina emuina'', commonly known as the Emu Mountain sheoak, is a shrub of the genus ''Allocasuarina'' native to Queensland.
The shrub has a spreading habit that typically grows to a height have and has smooth bark. It has long wiry nee ...
'' (Emu Mountain sheoak)
* ''
Allocasuarina eriochlamys''
* ''
Allocasuarina fibrosa'' (Woolly sheoak)
* ''
Allocasuarina filidens'' (Mount Beerwah sheoak)
* ''
Allocasuarina fraseriana'' (Western sheoak)
* ''
Allocasuarina glareicola''
* ''
Allocasuarina globosa
''Allocasuarina globosa'' is a species of flowering plant in the family Casuarinaceae and is endemic to a restricted part of inland Western Australia. It is a dioecious shrub that has more or less erect branchlets, its leaves reduced to scales in ...
''
* ''
Allocasuarina grampiana
''Allocasuarina grampiana'', commonly known as Grampians sheoak, is a species of flowering plant in the family Casuarinaceae and is endemic to the Grampians National Park in Victoria. It is a dioecious shrub that has branchlets up to long, the ...
''
* ''
Allocasuarina grevilleoides
''Allocasuarina grevilleoides'' is a shrub of the genus ''Allocasuarina'' native to a small area in the western Wheatbelt region of Western Australia.
The dioecious lignotuberous shrub typically grows to a height of . It is found in sandy and ...
''
* ''
Allocasuarina gymnanthera''
* ''
Allocasuarina helmsii
''Allocasuarina helmsii'' is a shrub of the genus ''Allocasuarina'' native to both South Australia[Allocasuarina huegeliana
''Allocasuarina huegeliana'', commonly known as rock sheoak or sighing sheoak, is a tree in the family Casuarinaceae. Endemic to Western Australia, it occurs mostly throughout the Wheatbelt region. It is now especially common on road verges, w ...]
'' (Rock sheoak)
* ''
Allocasuarina humilis
''Allocasuarina humilis'', commonly known as the dwarf sheoak or dwarf casuarina, is a woody shrub of the family Casuarinaceae endemic to the south-west of Western Australia.
Description
Unlike many sheoaks which grow into trees, ''Allocasuarin ...
'' (Dwarf sheoak)
* ''
Allocasuarina hystricosa''
Wege
* ''
Allocasuarina inophloia'' (Hairy oak)
* ''
Allocasuarina lehmanniana
''Allocasuarina lehmanniana'', commonly known as dune sheoak, is a shrub in the family Casuarinaceae. Endemic to Western Australia, it is widespread along on the coast from the Murchison River south to Israelite Bay.
Dune sheoak grows as an up ...
'' (Dune sheoak)
* ''
Allocasuarina littoralis
''Allocasuarina littoralis'', commonly known as black sheoak, black she-oak, or river black-oak, is an endemic medium-sized Australian tree (usually up to 8 metres, but sometimes to 15 metres - coarse shrub in exposed maritime areas). A. littoral ...
'' (Black sheoak)
* ''
Allocasuarina luehmannii'' (Bull-oak or buloke)
* ''
Allocasuarina mackliniana'' (Western sheoak)
* ''
Allocasuarina media''
* ''
Allocasuarina microstachya''
* ''
Allocasuarina misera''
* ''
Allocasuarina monilifera
''Allocasuarina monilifera'', commonly known as necklace sheoak, is a species of flowering plant in the family Casuarinaceae and is endemic to Tasmania. It is usually a monoecious, low-growing shrub that has branchlets up to long, the leaves re ...
''
* ''
Allocasuarina muelleriana'' (Slaty sheoak)
* ''
Allocasuarina nana''
* ''
Allocasuarina ophiolitica''
* ''
Allocasuarina paludosa
''Allocasuarina paludosa'', commonly known as the swamp sheoak or scrub sheoak, is a woody shrub of the family Casuarinaceae. It is endemic
Endemism is the state of a species being found in a single defined geographic location, such as an ...
'' (Scrub sheoak)
* ''
Allocasuarina paradoxa
''Allocasuarina paradoxa'' is a species of flowering plant in the family Casuarinaceae and is endemic to Victoria (state), Victoria. It is a Dioecy, dioecious or Monoecy, monoecious shrub that has branchlets up to long, the leaves reduced to ...
''
* ''
Allocasuarina pinaster
''Allocasuarina pinaster'', commonly known as compass bush, is a species of flowering plant in the family Casuarinaceae and is endemic to the south-west of Western Australia. It is a prickly, dioecious shrub resembling a pine tree and that has i ...
''
* ''
Allocasuarina portuensis
''Allocasuarina portuensis'', commonly known as the Nielsen Park she-oak, is an extremely rare plant growing in Sydney, Australia. Encountered as a shrub or small slender tree, up to tall, it has green drooping branchlets up to in length. It ...
''
* ''
Allocasuarina pusilla
''Allocasuarina pusilla'', commonly known as the heath oak-bush or the dwarf she-oak, is a species of ''Allocasuarina'' genera native to Australia.
The dioecious shrub typically grows to a height of . It is found in sandy soils of south eastern ...
'' (Dwarf sheoak)
* ''
Allocasuarina ramosissima''
* ''
Allocasuarina rigida
''Allocasuarina rigida'' is a species of the genus ''Allocasuarina'' native to Australia.
The dioecious shrub typically grows to a height of . It is found on volcanic outcrops in exposed situations in north eastern New South Wales and south east ...
''
* ''
Allocasuarina robusta''
* ''
Allocasuarina rupicola''
* ''
Allocasuarina scleroclada
''Allocasuarina scleroclada'' is a species of flowering plant in the family Casuarinaceae and is endemic to areas along the south coast of Western Australia. It is a straggly, dioecious shrub that has branchlets up to long, the leaves reduced t ...
''
* ''
Allocasuarina simulans
''Allocasuarina simulans'', commonly known as Nabiac casuarina, is a species of flowering plant in the family Casuarinaceae and is endemic to a restricted part of eastern New South Wales. It is a usually a dioecious shrub with branchlets up to ...
''
* ''
Allocasuarina spinosissima''
* ''
Allocasuarina striata'' (Small bull-oak)
* ''
Allocasuarina tessellata
''Allocasuarina tessellata'' is a species of flowering plant in the family Casuarinaceae and is endemic to the south-west of Western Australia. It is a dioecious shrub or tree that has more or less erect branchlets, the leaves reduced to scales i ...
''
* ''
Allocasuarina thalassoscopica
''Allocasuarina thalassoscopica'' is a species of ''Allocasuarina'' native to Australia.
The shrub typically grows to a height of .
It has a limited range and is restricted to a small area in south east Queensland and north-east New South Wale ...
''
* ''
Allocasuarina thuyoides
''Allocasuarina thuyoides'', commonly known as horned sheoak, is a species of flowering plant in the family Casuarinaceae and is endemic to the south-west of Western Australia. It is monoecious or dioecious shrub that has its leaves reduced to s ...
'' (Horned she-oak)
* ''
Allocasuarina tortiramula
''Allocasuarina tortiramula'', commonly known as twisted sheoak, is a species of flowering plant in the family Casuarinaceae and is endemic to a restricted area in the south-west of Western Australia. It is a dioecious shrub that has spreading, t ...
'' (Twisted sheoak)
* ''
Allocasuarina torulosa'' (Forest sheoak)
* ''
Allocasuarina trichodon
''Allocasuarina trichodon'' is a shrub of the genus ''Allocasuarina'' native to an area along the south coast in the Great Southern and Goldfields-Esperance regions of Western Australia
Western Australia (commonly abbreviated as WA) is a st ...
''
* ''
Allocasuarina verticillata'' (Drooping sheoak)
Allocasuarina verticillata
Windmill Outback Nursery, 2003-03-13. Retrieved 2007-01-23.
* ''Allocasuarina zephyrea
''Allocasuarina zephyrea'' is a species of flowering plant in the family Casuarinaceae and is endemic to Tasmani. It is a Dioecy, dioecious shrub that has branchlets up to long, the leaves reduced to scales in whorls of seven to nine or ten, t ...
''
Species names with uncertain taxonomic status
The status of the following species is unresolved:
* ''Allocasuarina decemilinanana''
References
External links
*
*
Research team
fro
IRD
working on Casuarinaceae
{{Taxonbar, from=Q135346
Fagales genera
Fagales of Australia