Cyathea australis
Encyclopedia
Cyathea australis, also known as the Rough Tree Fern, is a species of tree fern
native to southeastern Queensland
, New South Wales
and southern Victoria
in Australia
, as well as Tasmania
and Norfolk Island
. It grows in moist shady forest, both coastal and montane, at an altitude of up to 1280 m, often in the company of Dicksonia antarctica
. The massive erect trunk is usually up to 12 m tall, although specimens reaching 20 m have been reported from Queensland, Australia. Frond
s are bi- or tripinnate and may reach 4 m in length, occasionally even 6 m. These form a distinctive crown that is dark green above and lighter green below. The Tree Fern has quite adventitious roots, tubercles and hair-like follicles on its ‘trunk’.
Plants growing in southern Australia, often lose their fronds by the end of winter, as is the case with Cyathea dregei
in South Africa
. Characteristically of this species, stipe
bases are often retained around the trunk long after withering. They are covered with scale
s and conical, blunt spines towards the base. The scales range in colour from shiny brown to bicoloured (pale and brown) and are often distinctly twisted. Sori
are circular and occur on either side of the fertile pinnule midvein. True indusia are absent, although reduced scales may encircle the sori. C. australis is a highly variable taxon
, with several subspecies
and varieties
.
C. australis is a highly variable species. Plants from Norfolk Island
, belonging to the subspecies norfolkensis, are larger, more robust and differ primarily in scale characteristics. They are rare in cultivation. Further study is needed to determine whether this taxon
represents a separate species or not. C. australis appears to be related to Cyathea woollsiana.
C. australis was described by Robert Brown
in 1810 from a specimen collected on King Island
in Bass Strait
, off the coast of Tasmania. It is the type for the genus Alsophila, which has now been reduced to a section. The specific epithet
australis means "southern" and refers to this southerly location.
C. australis is a relatively hardy species and a popular landscape and container plant. Provided moisture levels remain high, it will tolerate frost and full sun, or shade in warmer regions. Although well known in its native country, this species is not common in cultivation outside of Australia.
In the horticultural
trade, most plants labeled as C. australis are in fact Cyathea cooperi
. Much confusion has existed between the two, especially in the United States, although they are quite distinct from one another. C. australis is relatively stout trunked and has a large number of closely spaced fronds emerging at one time,with a slower increase in trunk height. C. cooperi in contrast, grows more quickly with fewer fronds emerging each year and a much narrower trunk with the frond bases aligned vertically for some distance ("hugging" the trunk as it were), before arching outwards.
C. australis is also a robust tub plant and tolerant of salty winds. It is a popular cool climate hardy tree-fern, and adaptable to a variety of climates and soils.
Cyatheales
The order Cyatheales is a taxonomic division of the fern subclass, Cyatheatae, which includes the tree ferns. No clear morphological features characterize all of the Cyatheales, but DNA sequence data indicates that the order is monophyletic. Some species in the Cyatheales have tree-like growth...
native to southeastern Queensland
Queensland
Queensland 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 Wales
New South Wales
New 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...
and southern Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
in Australia
Australia
Australia , 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...
, as well as Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
and Norfolk Island
Norfolk Island
Norfolk Island is a small island in the Pacific Ocean located between Australia, New Zealand and New Caledonia. The island is part of the Commonwealth of Australia, but it enjoys a large degree of self-governance...
. It grows in moist shady forest, both coastal and montane, at an altitude of up to 1280 m, often in the company of Dicksonia antarctica
Dicksonia antarctica
Dicksonia antarctica, known as the Soft Tree Fern, Man Fern or Tasmanian Tree Fern, is an evergreen tree fern native to parts of Australia, namely south-east Queensland, coastal New South Wales and Victoria and Tasmania.- Anatomy and biology :...
. The massive erect trunk is usually up to 12 m tall, although specimens reaching 20 m have been reported from Queensland, Australia. Frond
Frond
The term frond refers to a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group...
s are bi- or tripinnate and may reach 4 m in length, occasionally even 6 m. These form a distinctive crown that is dark green above and lighter green below. The Tree Fern has quite adventitious roots, tubercles and hair-like follicles on its ‘trunk’.
Plants growing in southern Australia, often lose their fronds by the end of winter, as is the case with Cyathea dregei
Cyathea dregei
Cyathea dregei, also known as the Common Tree Fern and Gewone Boomvaring in Afrikaans, is a widespread species of tree fern in southern Africa...
in 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...
. Characteristically of this species, stipe
Stipe (botany)
In botany, a stipe is a stalk that supports some other structure. The precise meaning is different depending on which taxonomic group is being described....
bases are often retained around the trunk long after withering. They are covered with scale
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...
s and conical, blunt spines towards the base. The scales range in colour from shiny brown to bicoloured (pale and brown) and are often distinctly twisted. Sori
Sorus
A sorus is a cluster of sporangia .In fungi and lichens, the sorus is surrounded by an external layer. In some red algae it may take the form of a depression into the thallus....
are circular and occur on either side of the fertile pinnule midvein. True indusia are absent, although reduced scales may encircle the sori. C. australis is a highly variable taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
, with several subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
and varieties
Variety (biology)
In botanical nomenclature, variety is a taxonomic rank below that of species: as such, it gets a three-part infraspecific name....
.
C. australis is a highly variable species. Plants from Norfolk Island
Norfolk Island
Norfolk Island is a small island in the Pacific Ocean located between Australia, New Zealand and New Caledonia. The island is part of the Commonwealth of Australia, but it enjoys a large degree of self-governance...
, belonging to the subspecies norfolkensis, are larger, more robust and differ primarily in scale characteristics. They are rare in cultivation. Further study is needed to determine whether this taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
represents a separate species or not. C. australis appears to be related to Cyathea woollsiana.
C. australis was described by Robert Brown
Robert Brown (botanist)
Robert Brown was a Scottish botanist and palaeobotanist who made important contributions to botany largely through his pioneering use of the microscope...
in 1810 from a specimen collected on King Island
King Island, Tasmania
King Island is one of the islands that make up the state of Tasmania, Australia. It is located in the Roaring Forties of Bass Strait, off the north-western tip of the main island of Tasmania, about half way between Tasmania and the mainland state of Victoria. The southernmost point is called Stokes...
in Bass Strait
Bass Strait
Bass Strait is a sea strait separating Tasmania from the south of the Australian mainland, specifically the state of Victoria.-Extent:The International Hydrographic Organization defines the limits of the Bass Strait as follows:...
, off the coast of Tasmania. It is the type for the genus Alsophila, which has now been reduced to a section. The specific epithet
Epithet
An epithet or byname is a descriptive term accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, divinities, objects, and binomial nomenclature. It is also a descriptive title...
australis means "southern" and refers to this southerly location.
C. australis is a relatively hardy species and a popular landscape and container plant. Provided moisture levels remain high, it will tolerate frost and full sun, or shade in warmer regions. Although well known in its native country, this species is not common in cultivation outside of Australia.
In the horticultural
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
trade, most plants labeled as C. australis are in fact Cyathea cooperi
Cyathea cooperi
Cyathea cooperi, also known as the Australian tree fern, lacy tree fern, scaly tree fern, or Cooper’s tree fern, is a medium-to-large, fast growing tree fern native to Australia. This fern grows to in height with a thick trunk...
. Much confusion has existed between the two, especially in the United States, although they are quite distinct from one another. C. australis is relatively stout trunked and has a large number of closely spaced fronds emerging at one time,with a slower increase in trunk height. C. cooperi in contrast, grows more quickly with fewer fronds emerging each year and a much narrower trunk with the frond bases aligned vertically for some distance ("hugging" the trunk as it were), before arching outwards.
C. australis is also a robust tub plant and tolerant of salty winds. It is a popular cool climate hardy tree-fern, and adaptable to a variety of climates and soils.