Casuarina
Encyclopedia
Casuarina is a genus
of 17 species in the family Casuarinaceae
, native to Australasia
, southeast Asia
, and islands
of the western Pacific Ocean
. It was once treated as the sole genus in the family, but has been split into three genera (see Casuarinaceae
).
They are evergreen
shrub
s and tree
s growing to 35 m tall. The foliage consists of slender, much-branched green to grey-green twigs bearing minute scale-leaves
in whorls of 5–20. The flower
s are produced in small catkin
-like inflorescence
s; the flowers are simple spikes. Most species are dioecious
, but a few are monoecious
. The fruit
is a woody, oval structure superficially resembling a conifer cone
made up of numerous carpels
each containing a single seed
with a small wing. The generic name is derived from the Malay
word for the cassowary
, kasuari, alluding to the similarities between the bird's feathers and the plant's foliage, though the tree is presently called "Rhu" in current standard Malay.
Casuarina species are a food source of the larva
e of hepialid
moth
s; members of the genus Aenetus
, including A. lewinii and A. splendens, burrow horizontally into the trunk then vertically down. Endoclita malabaricus
also feeds on Casuarina. The noctuid
Turnip Moth
is also recorded feeding on Casuarina.
Casuarictin
, a type of tannin
, is found in the species within the genus.
Sources:
and subtropical
areas throughout the world. The tree has delicate, slender ultimate branches and leaves that are no more than scales, making the tree look more like a wispy conifer. The plants are very tolerant of windswept locations, and are widely planted as windbreak
s, although usually not in agricultural situations.
C. equisetifolia
is a common tropical seashore tree known as Common Ironwood, Beefwood, Bull-oak, or Whistling-pine and is often planted as a windbreak. The wood of this tree is used for shingles, fencing, and is said to make excellent, hot burning firewood.
C. oligodon has been planted in New Guinea in an ancient (more than 3,000 years) silviculture
by highland gardeners practicing an intensive traditional permaculture
. The wood of this tree is used for building-timber, furniture and tools and makes excellent firewood. The tree's root nodules are known to fix nitrogen, and it is traditionally prized for its ability to increase the soil's fertility. Its abundant leaf-fall
is high in nitrogen and traditionally prized for mulch
.
The resin
exuded from some casuarinas is edible and was a food source for Aboriginal
people.
Gardeners in Bermuda can appreciate that all parts of the casuarina tree (needles, sawdust, bark, and prepared mulch) can be useful in lowering the soil pH, as Bermuda's topography consists of naturally high pH limestone
rock, and perhaps only a foot of red or sandy soil. Lowering soil pH makes the soil more acidic, which can help Bermuda's biodiversity by growing acid-loving plants such as blueberries, blackberries, azaleas
, rhododendrons, and such plants that may be seen in similar hardiness zones
as Bermuda (USDA 9-11), such as plants found in New Zealand
and Florida
, which naturally have a lower pH soil than Bermuda, albeit some other environmental differences as well.
, C. glauca
and C. equisetifolia
have become naturalized
in several countries, including Argentina
, Cuba
, China
, Egypt
, Israel
, Iraq
, Mauritius
, Kenya
, Mexico
, South Africa
, Rio de Janeiro
, the Bahamas
and the southern United States
; in the United States it was introduced in the early 1900s, and is now considered an invasive species
. The species has nearly quadrupled in southern Florida
between 1993 and 2005, where it is known as Australian pine.
C. equisetifolia is widespread in the Hawaiian Islands
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 introduced, invasive plant in Bermuda
, where it was introduced to replace the Juniperus bermudiana
windbreaks killed by juniper blight in the 1940s. Now the ironwoods are growing on cliffs and sandy slopes strangling all surrounding plants, or covering them in needles; they also erode the cliffs by digging their roots deep into them and splitting them apart. Casuarinas are strongly suspected of having allelopathic
properties, as evidenced by the near absence of understory
once a mat of litter
develops around the plants.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of 17 species in the family Casuarinaceae
Casuarinaceae
Casuarinaceae is a family of dicotyledonous flowering plants placed in the order Fagales, consisting of 3 or 4 genera and approximately 70 species of trees and shrubs native to the Old World tropics , Australia, and the Pacific Islands...
, native to Australasia
Australasia
Australasia is a region of Oceania comprising Australia, New Zealand, the island of New Guinea, and neighbouring islands in the Pacific Ocean. The term was coined by Charles de Brosses in Histoire des navigations aux terres australes...
, southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
, and islands
Pacific Islands
The Pacific Islands comprise 20,000 to 30,000 islands in the Pacific Ocean. The islands are also sometimes collectively called Oceania, although Oceania is sometimes defined as also including Australasia and the Malay Archipelago....
of the western Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
. It was once treated as the sole genus in the family, but has been split into three genera (see Casuarinaceae
Casuarinaceae
Casuarinaceae is a family of dicotyledonous flowering plants placed in the order Fagales, consisting of 3 or 4 genera and approximately 70 species of trees and shrubs native to the Old World tropics , Australia, and the Pacific Islands...
).
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...
shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
s and tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s growing to 35 m tall. The foliage consists of slender, much-branched green to grey-green twigs bearing minute scale-leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
in whorls of 5–20. The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are produced in small catkin
Catkin
A catkin or ament is a slim, cylindrical flower cluster, with inconspicuous or no petals, usually wind-pollinated but sometimes insect pollinated . They contain many, usually unisexual flowers, arranged closely along a central stem which is often drooping...
-like inflorescence
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. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
s; the flowers are simple spikes. Most species are dioecious
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
, but a few are monoecious
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
. The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
is a woody, oval structure superficially resembling a conifer cone
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
made up of numerous carpels
Gynoecium
Gynoecium is most commonly used as a collective term for all carpels in a flower. A carpel is the ovule and seed producing reproductive organ in flowering plants. Carpels are derived from ovule-bearing leaves which evolved to form a closed structure containing the ovules...
each containing a single seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
with a small wing. The generic name is derived from the Malay
Malay language
Malay is a major language of the Austronesian family. It is the official language of Malaysia , Indonesia , Brunei and Singapore...
word for the cassowary
Cassowary
The cassowaries are ratites, very large flightless birds in the genus Casuarius native to the tropical forests of New Guinea, nearby islands and northeastern Australia. There are three extant species recognized today...
, kasuari, alluding to the similarities between the bird's feathers and the plant's foliage, though the tree is presently called "Rhu" in current standard Malay.
Casuarina species are a food source of the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e of hepialid
Hepialidae
The Hepialidae is a family of insects in the lepidopteran order. Moths of this family are often referred to as swift moths or ghost moths.-Taxonomy and systematics:...
moth
Moth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...
s; members of the genus Aenetus
Aenetus
Aenetus is a genus of moths of the family Hepialidae. There are 24 described species found in Indonesia, New Guinea, New Caledonia, Australia and New Zealand. Most species have green or blue forewings and reddish hindwings but some are predominantly brown or white...
, including A. lewinii and A. splendens, burrow horizontally into the trunk then vertically down. Endoclita malabaricus
Endoclita
Endoclita is a genus of moths of the family Hepialidae. There are 60 described species found in eastern and southeast Asia and the Indian subcontinent.- Species :*E. aboe - India*E. absurdus - China*E. actinidae - China...
also feeds on Casuarina. The noctuid
Noctuidae
The Noctuidae or owlet moths are a family of robustly-built moths that includes more than 35,000 known species out of possibly 100,000 total, in more than 4,200 genera. They constitute the largest family in the Lepidoptera....
Turnip Moth
Turnip Moth
The Turnip Moth is a moth of the family Noctuidae. It is a common European species, but it is also found in Asia and Africa, very likely having been spread by the international trade in nursery stock...
is also recorded feeding on Casuarina.
Casuarictin
Casuarictin
Casuarictin is an ellagitannin, a type of hydrolysable tannin. It can be found in Casuarina and Stachyurus species.The molecule is formed from tellimagrandin II, itself formed from pentagalloyl glucose via oxidation. Casuarictin is transformed into pedunculagin via loss of a gallate group, and...
, a type of tannin
Tannin
A tannin is an astringent, bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids.The term tannin refers to the use of...
, is found in the species within the genus.
Selected species
- Casuarina cristata Miq. (Northeastern AustraliaAustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
: QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
, New South WalesNew South WalesNew South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
). - Casuarina cunninghamianaCasuarina cunninghamianaCasuarina cunninghamiana is a she-oak species of the genus Casuarina. The native range extends from Daly River in the Northern Territory, north and east in Queensland and eastern New South Wales.-Description:...
Miq. – River Sheoak (Northern and eastern Australia: Northern TerritoriesNorthern TerritoryThe Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...
to New South Wales) - Casuarina equisetifoliaCasuarina equisetifoliaCasuarina equisetifolia is a she-oak species of the genus Casuarina. The native range extends from Burma and Vietnam throughout Malesia east to French Polynesia, New Caledonia, and Vanuatu, and south to Australia...
L. – Australian Pine, Beach Sheoak, Common Ironwood (Northern Australia, southeastern Asia, doubtfully native to MadagascarMadagascarThe Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
), ঝাউ in বাংলা (Bengali)Trees of IndiaSources: Common Trees of India, Pippa Mukherjee, World Wildlife Fund India/ Oxford University Press 1983, Flowering Trees and Shrubs in India, D.V. Cowen... - Casuarina glaucaCasuarina glaucaCasuarina glauca, commonly known as the swamp she-oak, is a species of Casuarina native to the east coast of Australia. It is found from central Queensland south to southern New South Wales. It has become naturalised in the Everglades in Florida where it is considered a weed.The larvae of the...
Sieber ex Spreng. Gray Sheoak, Longleaf Ironwood, Saltmarsh Ironwood, Swamp Oak (New South Wales) - Casuarina grandis L.A.S.Johnson (New GuineaNew GuineaNew Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
) - Casuarina junghuhniana Miq. (IndonesiaIndonesiaIndonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
) - Casuarina obesaCasuarina obesaCasuarina obesa, commonly known as Swamp She-oak or Swamp Oak, is a species of Casuarina that is closely related to C. glauca and C...
Miq. (Southern Australia: southwestern Western Australia, New South Wales [one site, now extinct], Victoria) - Casuarina oligodon L.A.S.Johnson (New Guinea)
- Casuarina pauperCasuarina pauperCasuarina pauper is an Australian tree species known as black oak. It is native to a band across southern Australia....
F.Muell. ex L.A.S.Johnson (Interior Australia)
Sources:
Formerly placed here
|
Allocasuarina luehmannii Allocasuarina luehmannii is a species of she-oak native to Australia. Stands are endangered by farming practices in the Wimmera region of western Victoria, where it is integral to the survival of the endangered southeastern subspecies of the Red-tailed Black Cockatoo for feeding and nesting.The... (R.T.Baker) L.A.S.Johnson (as C. luehmannii R.T.Baker) Allocasuarina nana Allocasuarina nana, commonly known as the Dwarf She-Oak, is a small plant found in eastern Australia. Often seen around one metre tall, it grows in exposed heathlands, ridges, clifftops on sandstone based soils... (Sieber ex Spreng.) L.A.S.Johnson (as C. nana Sieber ex Spreng.) Allocasuarina torulosa Allocasuarina torulosa is a tree which grows in sub-rainforest of Queensland and New South Wales, Australia. Originally described as Casuarina torulosa by William Aiton, it was moved to its current genus in 1982 by Australian botanist Lawrie Johnson... (Aiton) L.A.S.Johnson (as C. tenuissima Sieber ex Spreng. or C. torulosa Aiton) Allocasuarina verticillata Allocasuarina verticillata or drooping sheoak is a nitrogen fixing native tree of southeastern Australia. Originally collected in Tasmania and described as Casuarina verticillata by French naturalist Jean-Baptiste Lamarck in 1786, it was moved to its current genus in 1982 by Australian botanist... (Lam.) L.A.S.Johnson (as C. quadrivalvis Labill., C. stricta Aiton or C. verticillata Lam.) Gymnostoma sumatranum Gymnostoma sumatranum and the other members of this family are characterized by drooping equisetoid twigs, are evergreen, and monoecious or dioecious. The roots have nitrogen-fixing nodules. The foliage of this tropical angiosperm tree looks like that of gymnosperm pine trees which typically grow... (Jungh. ex de Vriese) L.A.S.Johnson (as C. sumatrana Jungh. ex de Vriese) |
Cultivation and uses
Commonly known as the she-oak, sheoak, ironwood, or beefwood, casuarinas are commonly grown in tropicalTropics
The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately N and the Tropic of Capricorn in the southern hemisphere at S; these latitudes correspond to the axial tilt of the Earth...
and subtropical
Subtropics
The subtropics are the geographical and climatical zone of the Earth immediately north and south of the tropical zone, which is bounded by the Tropic of Cancer and the Tropic of Capricorn, at latitudes 23.5°N and 23.5°S...
areas throughout the world. The tree has delicate, slender ultimate branches and leaves that are no more than scales, making the tree look more like a wispy conifer. The plants are very tolerant of windswept locations, and are widely planted as windbreak
Windbreak
A windbreak or shelterbelt is a plantation usually made up of one or more rows of trees or shrubs planted in such a manner as to provide shelter from the wind and to protect soil from erosion. They are commonly planted around the edges of fields on farms. If designed properly, windbreaks around a...
s, although usually not in agricultural situations.
C. equisetifolia
Casuarina equisetifolia
Casuarina equisetifolia is a she-oak species of the genus Casuarina. The native range extends from Burma and Vietnam throughout Malesia east to French Polynesia, New Caledonia, and Vanuatu, and south to Australia...
is a common tropical seashore tree known as Common Ironwood, Beefwood, Bull-oak, or Whistling-pine and is often planted as a windbreak. The wood of this tree is used for shingles, fencing, and is said to make excellent, hot burning firewood.
C. oligodon has been planted in New Guinea in an ancient (more than 3,000 years) silviculture
Silviculture
Silviculture is the practice of controlling the establishment, growth, composition, health, and quality of forests to meet diverse needs and values. The name comes from the Latin silvi- + culture...
by highland gardeners practicing an intensive traditional permaculture
Permaculture
Permaculture is an approach to designing human settlements and agricultural systems that is modeled on the relationships found in nature. It is based on the ecology of how things interrelate rather than on the strictly biological concerns that form the foundation of modern agriculture...
. The wood of this tree is used for building-timber, furniture and tools and makes excellent firewood. The tree's root nodules are known to fix nitrogen, and it is traditionally prized for its ability to increase the soil's fertility. Its abundant leaf-fall
Plant litter
Plant litter, leaf litter or tree litter is dead plant material, such as leaves, bark, needles, and twigs, that has fallen to the ground. Litter provides habitat for small animals, fungi, and plants, and the material may be used to construct nests. As litter decomposes, nutrients are released to...
is high in nitrogen and traditionally prized for mulch
Mulch
In agriculture and gardening, is a protective cover placed over the soil to retain moisture, reduce erosion, provide nutrients, and suppress weed growth and seed germination. Mulching in gardens and landscaping mimics the leaf cover that is found on forest floors....
.
The resin
Resin
Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials...
exuded from some casuarinas is edible and was a food source for Aboriginal
Indigenous Australians
Indigenous Australians are the original inhabitants of the Australian continent and nearby islands. The Aboriginal Indigenous Australians migrated from the Indian continent around 75,000 to 100,000 years ago....
people.
Gardeners in Bermuda can appreciate that all parts of the casuarina tree (needles, sawdust, bark, and prepared mulch) can be useful in lowering the soil pH, as Bermuda's topography consists of naturally high pH limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
rock, and perhaps only a foot of red or sandy soil. Lowering soil pH makes the soil more acidic, which can help Bermuda's biodiversity by growing acid-loving plants such as blueberries, blackberries, azaleas
Azalea
Azaleas are flowering shrubs comprising two of the eight subgenera of the genus Rhododendron, Pentanthera and Tsutsuji . Azaleas bloom in spring, their flowers often lasting several weeks...
, rhododendrons, and such plants that may be seen in similar hardiness zones
Hardiness zone
A hardiness zone is a geographically defined area in which a specific category of plant life is capable of growing, as defined by climatic conditions, including its ability to withstand the minimum temperatures of the zone...
as Bermuda (USDA 9-11), such as plants found in New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
and Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, which naturally have a lower pH soil than Bermuda, albeit some other environmental differences as well.
Invasive species
C. cunninghamianaCasuarina cunninghamiana
Casuarina cunninghamiana is a she-oak species of the genus Casuarina. The native range extends from Daly River in the Northern Territory, north and east in Queensland and eastern New South Wales.-Description:...
, C. glauca
Casuarina glauca
Casuarina glauca, commonly known as the swamp she-oak, is a species of Casuarina native to the east coast of Australia. It is found from central Queensland south to southern New South Wales. It has become naturalised in the Everglades in Florida where it is considered a weed.The larvae of the...
and C. equisetifolia
Casuarina equisetifolia
Casuarina equisetifolia is a she-oak species of the genus Casuarina. The native range extends from Burma and Vietnam throughout Malesia east to French Polynesia, New Caledonia, and Vanuatu, and south to Australia...
have become naturalized
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
in several countries, including Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
, Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
, China
Mainland China
Mainland China, the Chinese mainland or simply the mainland, is a geopolitical term that refers to the area under the jurisdiction of the People's Republic of China . According to the Taipei-based Mainland Affairs Council, the term excludes the PRC Special Administrative Regions of Hong Kong and...
, Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
, Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
, Iraq
Iraq
Iraq ; officially the Republic of Iraq is a country in Western Asia spanning most of the northwestern end of the Zagros mountain range, the eastern part of the Syrian Desert and the northern part of the Arabian Desert....
, Mauritius
Mauritius
Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...
, Kenya
Kenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
, Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
, Rio de Janeiro
Rio de Janeiro
Rio de Janeiro , commonly referred to simply as Rio, is the capital city of the State of Rio de Janeiro, the second largest city of Brazil, and the third largest metropolitan area and agglomeration in South America, boasting approximately 6.3 million people within the city proper, making it the 6th...
, the Bahamas
The Bahamas
The Bahamas , officially the Commonwealth of the Bahamas, is a nation consisting of 29 islands, 661 cays, and 2,387 islets . It is located in the Atlantic Ocean north of Cuba and Hispaniola , northwest of the Turks and Caicos Islands, and southeast of the United States...
and the southern United States
Southern United States
The Southern United States—commonly referred to as the American South, Dixie, or simply the South—constitutes a large distinctive area in the southeastern and south-central United States...
; in the United States it was introduced in the early 1900s, and is now considered an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
. The species has nearly quadrupled in southern Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
between 1993 and 2005, where it is known as Australian pine.
C. equisetifolia is widespread in the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
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 introduced, invasive plant in Bermuda
Flora and fauna in Bermuda
The flora and fauna of Bermuda forms part of a unique ecosystem thanks to Bermuda's isolation from the mainland of North America. There are a wide range of endemic species and the islands form a distinct ecoregion, the Bermuda subtropical conifer forests....
, where it was introduced to replace the Juniperus bermudiana
Juniperus bermudiana
Juniperus bermudiana is a species of juniper endemic to Bermuda. This species is most commonly known as Bermuda cedar although, like most "cedars" it is not a true cedar ; a more botanically accurate name would be Bermuda juniper, but this term is extremely rare.It is an evergreen tree growing up...
windbreaks killed by juniper blight in the 1940s. Now the ironwoods are growing on cliffs and sandy slopes strangling all surrounding plants, or covering them in needles; they also erode the cliffs by digging their roots deep into them and splitting them apart. Casuarinas are strongly suspected of having allelopathic
Allelopathy
Allelopathy is a biological phenomenon by which an organism produces one or more biochemicals that influence the growth, survival, and reproduction of other organisms. These biochemicals are known as allelochemicals and can have beneficial or detrimental effects on the target organisms...
properties, as evidenced by the near absence of understory
Understory
Understory is the term for the area of a forest which grows at the lowest height level below the forest canopy. Plants in the understory consist of a mixture of seedlings and saplings of canopy trees together with understory shrubs and herbs...
once a mat of litter
Plant litter
Plant litter, leaf litter or tree litter is dead plant material, such as leaves, bark, needles, and twigs, that has fallen to the ground. Litter provides habitat for small animals, fungi, and plants, and the material may be used to construct nests. As litter decomposes, nutrients are released to...
develops around the plants.