''Casuarina'', also known as she-oak, Australian pine and native pine, is a genus of flowering plants 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, the Indian subcontinent,

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

islands This is a list of the lists of islands in the world grouped by country, by continent, by body of water, and by other classifications. For rank-order lists, see the #Other lists of islands, other lists of islands below. Lists of islands by count ...

of the western Pacific Ocean, and eastern Africa. Plants in the genus ''Casuarina'' are

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system comparable with gynomonoecy, andromonoecy and trimonoecy, and contras ...

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 ...

trees with green, pendulous,

photosynthetic Photosynthesis ( ) is a Biological system, system of biological processes by which Photoautotrophism, photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical ener ...

branchlets, the leaves reduced to small scales arranged 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 ...

around the branchlets, the male and female flowers arranged in separate spikes, the fruit a cone containing grey or yellowish-brown winged seeds.

Description

Plants in the genus ''Casuarina'' are dioecious trees (apart from ''C. equisetifolia'' that is monoecious), with fissured or scaly greyish-brown to black bark. They have soft, pendulous, green,

branchlets, the leaves reduced to scale-like leaves arranged in whorls of 5 to 20 around the branchlets. The branchlets are segmented at each whorl with deep furrows that conceal the

stoma In botany, a stoma (: stomata, from Greek language, Greek ''στόμα'', "mouth"), also called a stomate (: stomates), is a pore found in the Epidermis (botany), epidermis of leaves, stems, and other organs, that controls the rate of gas exc ...

tes. Male flowers are arranged along branchlets in spikes with persistent bracteoles, female flowers in spikes on short side-branches (effectively " peduncles") that differ in appearance from vegetative branchlets. After fertilisation, the female spikes develop into "cones" with thin, woody bracteoles that extend well beyond the cone body. The cones enclose grey or yellowish-brown winged seed known as samaras.

Ecology

''Casuarina'' are attacked by a range of herbivorous insects. * Hymenoptera: The wasps '' Bootanelleus orientalis'' and another '' Bootanelleus'' species ( Torymidae) feed on seeds. '' Selitrichodes casuarinae'' and '' S. utilis'' (

Eulophidae The Eulophidae is a large family of hymenopteran insects, with over 4,300 described species in some 300 genera. The family includes the genus '' Elasmus'', which used to be treated as a separate family, "Elasmidae", and is now treated as a subfa ...

) induce

gall Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or war ...

s. * Lepidoptera: Most lepidopteran herbivores are in the family

Oecophoridae Oecophoridae (concealer moths) is a family of small moths in the superfamily Gelechioidea. The phylogeny and systematics of gelechoid moths are still not fully resolved, and the circumscription of the Oecophoridae is strongly affected by this. ...

. '' Zauclophora pelodes'', '' Araeostoma aenicta'' and '' Lichenaula'' sp. feed on leaves, and the latter two are also leaf tiers. '' Cryptophasa irrorata'' bores in branches and stems. Outside of Oecophoridae, there are fruit- and leaf-feeders in families

Carposinidae Carposinidae, the "fruitworm moths", is a family of insects in the order Lepidoptera. These moths are narrower winged than Copromorphidae, with less rounded forewing tips. Males often have conspicuous patches of scales on either surface (Dugdal ...

and

Gelechiidae The Gelechiidae are a family of moths commonly referred to as twirler moths or gelechiid moths. They are the namesake family of the huge and little-studied Taxonomic rank, superfamily Gelechioidea, and the family's taxonomy (biology), taxonomy ...

. * Curculionidae: A weevil in genus '' Haplonyx'' feeds on cones. The genera '' Misophrice'' and '' Apion'' have also been recorded on ''Casuarina'', but the nature of their associations is unknown. * Hemiptera: '' Casuarinicola'' jumping plant lice (

Triozidae Triozidae is one of seven families, collectively referred to as Psylloidea, plant lice, based on the type genus ''Trioza''. They had traditionally been considered part of a single family, Psyllidae, but recent classifications divide the superfam ...

) feed on sap of ''Casuarina.'' Another hemipteran associated with this genus is the felt scale '' Choneochiton casuarinae'' ( Eriococcidae). * Diptera: The gall midge '' Ophelmodiplosis clavata'' (

Cecidomyiidae Cecidomyiidae is a family of diptera, flies known as gall midges or gall gnats. As the name implies, the larvae of most gall midges feed within plant tissue, creating abnormal plant growths called galls. Cecidomyiidae are very fragile small in ...

) induces galls on branchlet tips.

Taxonomy

The genus ''Casuarina'' was first formally described in 1759 by

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

in ''

Amoenitates Academicae Amoenitates Academicae is the title of a multi-volume zoological and botanical publication (published during 1749–1790) consisting of the dissertations of the students of Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), ...

'' and the first species he described (the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

) was ''

Casuarina equisetifolia ''Casuarina equisetifolia'', commonly known as coastal she-oak, horsetail she-oak, ironwood, beach sheoak, beach casuarina, whistling tree or Australian pine is a species of flowering plant in the family Casuarinaceae and is native to Australia, ...

''. The generic name is derived from the Malay word for the

cassowary Cassowaries (; Biak: ''man suar'' ; ; Papuan: ''kasu weri'' ) are flightless birds of the genus ''Casuarius'', in the order Casuariiformes. They are classified as ratites, flightless birds without a keel on their sternum bones. Cassowaries a ...

, ''kasuari'', alluding to the similarities between the bird's feathers and the plant's foliage.

Species List

The following is a list of ''Casuarina'' species accepted by

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

as of April 2023: * '' Casuarina collina'' Poiss. ex Pancher & Sebert (

New Caledonia New Caledonia ( ; ) is a group of islands in the southwest Pacific Ocean, southwest of Vanuatu and east of Australia. Located from Metropolitan France, it forms a Overseas France#Sui generis collectivity, ''sui generis'' collectivity of t ...

) * ''

Casuarina cristata ''Casuarina cristata'', commonly known as belah or muurrgu, is a species of flowering plant in the family Casuarinaceae and is endemic to inland eastern Australia. It is a tree with fissured or scaly bark, sometimes drooping branchlets, the lea ...

'' Miq. – belah, muurrgu (Qld., N.S.W.). * '' Casuarina cunninghamiana'' Miq. – river oak, river sheoak, creek oak (Qld., N.S.W., A.C.T., N.T.) * ''

'' L. – coastal she-oak, horsetail she-oak (South Asia, Southeast Asia, Australia) * '' Casuarina glauca'' Sieber ex Spreng. – swamp she-oak, swamp buloke, marsh sheoak (Qld., N.S.W.) * '' Casuarina grandis'' L.A.S.Johnson (

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

) * '' Casuarina junghuhniana'' Miq. (Indonesia) * '' Casuarina obesa'' Miq. – swamp she-oak, swamp oak, western swamp oak (W.A., S.A., Vic., N.S.W.) * '' Casuarina oligodon'' L.A.S.Johnson (New Guinea) * '' Casuarina orophila'' L.A.S.Johnson (New Guinea) * '' Casuarina pauper'' F.Muell. ex L.A.S.Johnson – black oak, belah, kariku (W.A., S.A., Qld., N.S.W., Vic.) * '' Casuarina potamophila'' Schltr. (New Caledonia) * '' Casuarina tenella'' Schltr. (New Caledonia) * '' Casuarina teres'' Schltr. (New Caledonia) In 1982, Lawrence Johnson raised the genera ''

Allocasuarina ''Allocasuarina'', commonly known as sheoak or she-oak, is a genus of flowering plants in the family Casuarinaceae and is endemic to Australia. Plants in the genus ''Allocasuarina'' are trees or shrubs with soft, pendulous, green branchlets, th ...

'' and ''

Gymnostoma ''Gymnostoma'' is a genus of about eighteen species of trees and shrubs, constituting one of the four genera of the plant family Casuarinaceae. The species grow naturally in the tropics, including at high elevations having temperate climates, ...

'' in the ''

Journal of the Adelaide Botanic Gardens The Adelaide Botanic Garden is a public garden at the north-east corner of the Adelaide city centre, in the Adelaide Park Lands. It encompasses a fenced garden on North Terrace (between Lot Fourteen, the site of the old Royal Adelaide Hospita ...

'', and transferred some species previously included in ''Casuarina'' to the new genera. The species of ''Allocasuarina'' previously in ''Casuarina'' are: '' A. acuaria'', '' A. acutivalvis'', '' A. campestris'', '' A. corniculata'', '' A. decaisneana'', '' A. decussata'', '' A. dielsiana'', '' A. distyla'', '' A. drummondiana'', '' A. drummondiana'', '' A. fraseriana'', '' A. grevilleoides'', '' A. helmsii'', '' A. huegeliana'', '' A. humilis'', '' A. inophloia'', ''A. lehmanniana'' subsp. ''lehmanniana'', '' A. littoralis'', '' A. luehmannii'', '' A. microstachya'', '' A. monilifera'', '' A. muelleriana'', '' A. nana'', '' A. paludosa'', '' A. paradoxa'', '' A. pinaster'', '' A. pusilla'', '' A. ramosissima'', '' A. rigida'', '' A. robusta'', '' A. striata'', '' A. tessellata'', '' A. thuyoides'', '' A. torulosa'', '' A. trichodon'' and '' A. verticillata''. The species of ''Gymnostoma'' previously included in ''Casuarina'' are '' G. chamaecyparis'', '' G. deplancheanum'', '' G. intermedium'', '' G. leucodon'', '' G. nobile'', '' G. nodiflorum'', '' G. papuanum'', '' G. poissonianum'', '' G. rumphianum'' and '' G. sumatranum'' and '' G. webbianum''.

Invasive species

'' C. cunninghamiana'', '' C. glauca'' and '' C. equisetifolia'' have become

naturalized Naturalization (or naturalisation) is the legal act or process by which a non-national of a country acquires the nationality of that country after birth. The definition of naturalization by the International Organization for Migration of the ...

in many countries, including

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Cuba Cuba, officially the Republic of Cuba, is an island country, comprising the island of Cuba (largest island), Isla de la Juventud, and List of islands of Cuba, 4,195 islands, islets and cays surrounding the main island. It is located where the ...

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the Bahamas The Bahamas, officially the Commonwealth of The Bahamas, is an Archipelagic state, archipelagic and island country within the Lucayan Archipelago of the Atlantic Ocean. It contains 97 per cent of the archipelago's land area and 88 per cent of ...

, and

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. They are considered 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 ...

USFS FEIS
''Casuarina''
/ref>USDA Forest service

in the United States, especially in southern

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 ...

where they have nearly quadrupled in number between 1993 and 2005 and are called the Australian pine. ''C. equisetifolia'' is widespread in the

Hawaiian Islands The Hawaiian Islands () are an archipelago of eight major volcanic islands, several atolls, and numerous smaller islets in the Pacific Ocean, North Pacific Ocean, extending some from the Hawaii (island), island of Hawaii in the south to nort ...

where it grows both on the seashore in dry, salty, calcareous soils and up in the mountains in high rainfall areas on volcanic soils. It is also an invasive plant in

, where it was introduced to replace the ''

Juniperus bermudiana ''Juniperus bermudiana'' is a species of juniper endemic to Bermuda. This species is most commonly known as Bermuda cedar, but is also referred to as Bermuda juniper ( Bermudians refer to it simply as ''cedar''). Historically, this tree formed w ...

'' windbreaks killed by a scale insect in the 1940s.

References

External links

* {{Authority control Fagales genera