''Casuarina cunninghamiana'', commonly known as river oak, river sheoak or creek oak, is a species of flowering plant in the family

Casuarinaceae The Casuarinaceae are a family of dicotyledonous flowering plants placed in the order Fagales, consisting of four genera and 91 species of trees and shrubs native to eastern Africa, Australia, Southeast Asia, Malesia, Papuasia, and the Pacific ...

and is native to Australia and New Guinea. It is a tree with fissured and scaly bark, sometimes drooping branchlets, the leaves reduced to scales in

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). In nature File:Photograph and axial plane floral diagram ...

of 6 to 10, the fruit long containing winged seeds (

samaras Samaras (; feminine: Samara) is a Greek surname meaning 'saddler'. Notable people with the surname include: * Antonis Samaras (born 1951), Greek politician; Prime Minister of Greece, 2012–15 * Georgios Samaras (born 1985), Greek footballer * I ...

) long.

Description

''Casuarina cunninghamiana'' is a

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

tree that typically grows to a height of , has a DBH of . Its bark is finely fissured, scaly and greyish brown. The branchlets are often drooping, long, the leaves reduced to scale-like teeth long, arranged in whorls of 6 to 10 around the branchlets. The sections of branchlet between the leaf whorls (the "articles") are long and wide. The flowers on male trees are arranged in spikes long, the

anthers The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filamen ...

long. The female cones are on a peduncle long and sparsely covered with soft hairs. Mature cones are usually long and in diameter, the samaras long.

Taxonomy

''Casuarina cunninghamiana'' was first formally described in 1848 by Friedrich Miquel in his book ''Revisio critica Casuarinarum'' from specimens collected by Allan Cunningham near

Moreton Bay Moreton Bay is a bay located on the eastern coast of Australia from central Brisbane, Queensland. It is one of Queensland's most important coastal resources. The waters of Moreton Bay are a popular destination for recreational anglers and are ...

. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

(''cunninghamiana'') honours the collector of the

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * ...

specimens. In 1989, Lawrie Johnson and Alex George described subsp. ''miodon'' in the ''

Flora of Australia The flora of Australia comprises a vast assemblage of plant species estimated to over 21,000 vascular and 14,000 non-vascular plants, 250,000 species of fungi and over 3,000 lichens. The flora has strong affinities with the flora of Gondwana, ...

'', and the name, and that of the

autonym Autonym may refer to: * Autonym, the name used by a person to refer to themselves or their language; see Exonym and endonym * Autonym (botany), an automatically created infrageneric or infraspecific name See also * Nominotypical subspecies, in zo ...

are accepted by the

Australian Plant Census The Australian Plant Census (APC) provides an online interface to currently accepted, published, scientific names of the vascular flora of Australia, as one of the output interfaces of the national government Integrated Biodiversity Information Sys ...

: *''Casuarina cunninghamiana'' Miq. subsp. ''cunninghamiana'' is a tree to , the articles long with 8 to 10 teeth. *''Casuarina cunninghamiana'' subsp. ''miodon'' L.A.S.Johnson is a tree to , the articles long with 6 or 7 teeth.

Distribution and habitat

This casuarina mainly grows in pure stands in open forest on the banks of freshwater rivers and streams in Australia and New Guinea. Subspecies ''cunninghamiana'' occurs from Laura,

Chillagoe Chillagoe is a rural town and locality in the Shire of Mareeba, Queensland, Australia. In the , the locality of Chillagoe had a population of 214 people. It was once a thriving mining town for a range of minerals, but is now reduced to a small ...

and

Augathella Augathella is a rural town and locality in the Shire of Murweh, Queensland, Australia. In the , the locality of Augathella had a population of 328 people. Geography Augathella lies on the Matilda Highway, is north of the town of Charlevil ...

in Queensland to

Condobolin Condobolin is a town in the west of the Central West region of New South Wales, Australia, on the Lachlan River. At the , Condobolin had a population of 3,185. History Prior to European settlement, the area was inhabited by the Wiradjuri pe ...

and

Narrandera Narrandera ( ), until around 1949 also spelled "Narandera", is a town located in the central Riverina region of south-western New South Wales, Australia. The town lies on the junction of the Newell Highway, Newell and Sturt Highway, Sturt highwa ...

in New South Wales, and the

Australian Capital Territory The Australian Capital Territory (ACT), known as the Federal Capital Territory until 1938, is an internal States and territories of Australia, territory of Australia. Canberra, the capital city of Australia, is situated within the territory, an ...

. Subspecies ''miodon'' occurs between the Daly River in the north of the Northern Territory to the

Gulf of Carpentaria The Gulf of Carpentaria is a sea off the northern coast of Australia. It is enclosed on three sides by northern Australia and bounded on the north by the eastern Arafura Sea, which separates Australia and New Guinea. The northern boundary ...

in Queensland.

Uses

River oak is widely recognised as an important tree for stabilising riverbanks and for soil erosion prevention accepting wet and dry soils. The foliage is quite palatable to stock.

Invasive species

''Casuarina cunninghamiana'' is an

invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

in the

Everglades The Everglades is a natural region of flooded grasslands in the southern portion of the U.S. state of Florida, comprising the southern half of a large drainage basin within the Neotropical realm. The system begins near Orlando with the K ...

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

and in South Africa.

References

{{Authority control cunninghamiana Trees of Australia Fagales of Australia Flora of Queensland Flora of New South Wales Flora of the Northern Territory Flora of the Australian Capital Territory Drought-tolerant trees Taxa named by Friedrich Anton Wilhelm Miquel Plants described in 1848