The tree ferns are arborescent (tree-like)

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except t ...

s that grow with a trunk elevating the

frond A frond is 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. Other botanists allow the term frond to also apply to the lar ...

s above ground level, making them

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

s. Many extant tree ferns are members of the order

Cyatheales The order Cyatheales, which includes most tree ferns, is a taxonomic order of the fern class, Polypodiopsida. No clear morphological features characterize all of the Cyatheales, but DNA sequence data indicate the order is monophyletic. Some sp ...

, to which belong the families

Cyatheaceae The Cyatheaceae are a family of ferns, the scaly tree ferns, one of eight families in the order Cyatheales in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the family may defined much more broadly (Cyatheaceae '' ...

(scaly tree ferns),

Dicksoniaceae Dicksoniaceae is a group of tropical, subtropical and warm temperate ferns, treated as a family in the Pteridophyte Phylogeny Group classification of 2016 (PPG I), and counting 30-40 species. Alternatively, the family may be sunk into a very broa ...

Metaxyaceae ''Metaxya'' is a neotropical genus of ferns in the order Cyatheales. It is the only genus in the family Metaxyaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the genus may be placed in the subfamily Metax ...

, and

Cibotiaceae ''Cibotium'' (from Ancient Greek language, Greek , ''kibṓtion'', "little chest" or "box"), also known as manfern, is a genus of 11 species of tropical Cyatheales, tree ferns. It is the only genus in family Cibotiaceae in the Pteridophyte Phylog ...

. It is estimated that Cyatheales originated in the early Jurassic, and is the third group of ferns known to have given rise to tree-like forms. The others are the extinct ''

Tempskya ''Tempskya'' is an Extinction, extinct genus of tree fern that lived during the Cretaceous, Cretaceous period. Fossils have been found across both the Northern and Southern hemispheres. The growth habit of ''Tempskaya'' was unlike that of any liv ...

'' of uncertain position, and

Osmundales Osmundaceae (royal fern family) is a family of ferns containing four to six extant genera and 18–25 known species. It is the only living family of the order Osmundales in the class Polypodiopsida (ferns) or in some classifications the only ord ...

where the extinct Guaireaceae and some members of

Osmundaceae Osmundaceae (royal fern family) is a family of ferns containing four to six extant genera and 18–25 known species. It is the only living family of the order Osmundales in the class Polypodiopsida (ferns) or in some classifications the only ord ...

also grew into trees. In addition there were the Psaroniaceae and Tietea in the

Marattiales Marattiaceae is the only family of extant (living) ferns in the order Marattiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), Marattiales is the only order in the subclass Marattiidae. The family has six genera and about ...

, which is the sister group to most living ferns including Cyatheales. Other ferns which are also tree ferns, are ''

Leptopteris The fern genus ''Leptopteris'' is a small group of plants found growing in the Pacific Islands, New Guinea and Australia. They are similar to ferns in the related genus ''Todea'', and were originally included in that genus. However, the very thi ...

'' and ''

Todea The fern genus ''Todea'' is known from only two living species. ''Todea barbara'' L., known as the king fern, is native to South Africa, New Zealand, and Australia while '' Todea papuana'' H. is known only from Papua New Guinea. Species in the ge ...

'' in the family Osmundaceae, which can achieve short trunks under a metre tall. Fern species with short trunks in the genera ''

Blechnum ''Blechnum'', known as hard fern, is a genus of ferns in the family Blechnaceae, subfamily Blechnoideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Two very different circumscriptions of the genus are used by d ...

'', '' Cystodium'' and ''

Sadleria ''Sadleria'' is a genus of six species of ferns in the family Blechnaceae, all endemic to Hawaii.Fern pages''Sadleria''/ref> Taxonomy Georg Friedrich Kaulfuss distinguished the genus in 1824 based on samples of ''S. cyatheoides'' acquired by A ...

'' from the order

Polypodiales The order Polypodiales encompasses the major lineages of polypod ferns, which comprise more than 80% of today's fern species. They are found in many parts of the world including tropical, semitropical and temperate areas. Description Polypodiale ...

, and smaller members of Cyatheales like ''

Calochlaena ''Calochlaena'' is a genus of ferns within the family Dicksoniaceae. Although these ground ferns resemble bracken, they are only distantly related. Five species are known from Melanesia, Polynesia and eastern Australia. '' Calochlaena dubia'', i ...

'', '' Cnemedaria'', '' Culcita'' (mountains only tree fern), ''

Lophosoria Lophosoria is a genus of tree ferns within the family Dicksoniaceae. Although it is confined to tropical America in modern times, there is fossil evidence that it was once spread throughout Gondwana with the exception of New Zealand N ...

'' and ''

Thyrsopteris ''Thyrsopteris'' is a genus of tree fern. It contains a single living species, ''Thyrsopteris elegans'', endemic to the Juan Fernandez Archipelago off the coast of Chile. ''Thyrsopteris'' is the only genus in the family Thyrsopteridaceae in the ...

'' are also considered tree ferns.

Range

Tree ferns are found growing in tropical and subtropical areas worldwide, as well as cool to temperate

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

s in

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 ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

and neighbouring regions (e.g.

Lord Howe Island Lord Howe Island (; formerly Lord Howe's Island) is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, part of the Australian state of New South Wales. It lies directly east of mainland P ...

, etc.). Like all ferns, tree ferns reproduce by means of

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s formed on the undersides of the fronds.

Description

The fronds of tree ferns are usually very large and multiple-

pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and in ...

. Their trunk is actually a vertical and modified

rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

, and

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...

y tissue is absent. To add strength, there are deposits of

lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity ...

in the cell walls and the lower part of the stem is reinforced with thick, interlocking mats of tiny roots. If the

crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...

of ''Dicksonia antarctica'' (the most common species in gardens) is damaged, it will inevitably die because that is where all the new growth occurs. But other clump-forming tree fern species, such as ''D. squarrosa'' and ''D. youngiae'', can regenerate from basal offsets or from "pups" emerging along the surviving trunk length. Tree ferns often fall over in the wild, yet manage to re-root from this new prostrate position and begin new vertical growth.

Uses

Tree-ferns have been cultivated for their beauty alone; a few, however, were of some economic application, chiefly as sources of starch. The ''Alsophila excelsa'' of

Norfolk Island Norfolk Island (, ; Norfuk: ''Norf'k Ailen'') is an external territory of Australia located in the Pacific Ocean between New Zealand and New Caledonia, directly east of Australia's Evans Head and about from Lord Howe Island. Together with ...

was threatened with extinction for the sake of its

sago Sago () is a starch extracted from the pith, or spongy core tissue, of various tropical palm stems, especially those of ''Metroxylon sagu''. It is a major staple food for the lowland peoples of New Guinea and the Maluku Islands, where it is ...

-like

pith Pith, or medulla, is a tissue in the stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other ...

, which was eaten by hogs. ''Cyathea medullaris'' also furnished a kind of sago to the natives of New Zealand, Queensland and the Pacific islands. A

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...

nese species of ''Dicksonia'' (''D. chrysotricha'') furnishes silky hairs, which were once imported as a

styptic An antihemorrhagic (antihæmorrhagic) agent is a substance that promotes hemostasis (stops bleeding). It may also be known as a hemostatic (also spelled haemostatic) agent. Antihemorrhagic agents used in medicine have various mechanisms of action: ...

, and the long silky or wooly hairs, abundant on the stem and frond-leaves in the various species of ''Cibotium'' have not only been put to a similar use, but in the

Hawaiian Islands The Hawaiian Islands ( haw, Nā Mokupuni o Hawai‘i) are an archipelago of eight major islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost Kur ...

furnished wool for stuffing mattresses and cushions, which was formerly an article of export.

Species

250px, Transplanted ''Dicksonia antarctica'' tree ferns at Combe Martin Wildlife and Dinosaur Park, North Devon, England It is not certain the exact number of species of tree ferns there are, but it may be close to 600-700 species. Many species have become

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

in the last century as forest habitats have come under pressure from human intervention. *''

'' (tropical America, 1 species) *''

Metaxya ''Metaxya'' is a neotropical genus of ferns in the order Cyatheales. It is the only genus in the family Metaxyaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the genus may be placed in the subfamily Metax ...

'' (tropical America, 1 species) *''

Sphaeropteris ''Sphaeropteris'' is a genus of tree fern in the family Cyatheaceae. It has been treated as a subgenus within the genus ''Cyathea'', but is accepted in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Description Species of '' ...

'' (tropical America,

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

, the

Marquesas The Marquesas Islands (; french: Îles Marquises or ' or '; Marquesan: ' ( North Marquesan) and ' ( South Marquesan), both meaning "the land of men") are a group of volcanic islands in French Polynesia, an overseas collectivity of France in t ...

, and

Pitcairn Island Pitcairn Island is the only inhabited island of the Pitcairn Islands, of which many inhabitants are descendants of mutineers of HMS ''Bounty''. Geography The island is of volcanic origin, with a rugged cliff coastline. Unlike many other ...

, about 120 species) *'' Alsophila'' (pantropic area, about 230 species) *''

Nephelea ''Cyathea'' is a genus of tree ferns, the type genus of the fern order Cyatheales. The genus name ''Cyathea'' is derived from the Greek ''kyatheion'', meaning "little cup", and refers to the cup-shaped sori on the underside of the fronds. De ...

'' (tropical America, about 30 species) *'' Trichipteris'' (tropical America, about 90 species) *''

Cyathea ''Cyathea'' is a genus of tree ferns, the type genus of the fern order Cyatheales. The genus name ''Cyathea'' is derived from the Greek ''kyatheion'', meaning "little cup", and refers to the cup-shaped sori on the underside of the fronds. Des ...

'' (tropical America, Australasia, about 110 species) *'' Cnemidaria'' (tropical America, about 40 species) *''

Dicksonia ''Dicksonia'' is a genus of tree ferns in the order Cyatheales. It is regarded as related to ''Cyathea'', but is considered to retain more primitive traits, dating back at least to the Jurassic and Cretaceous periods. The fossil record includes ...

'' (tropics and southern subtropics in

Island Southeast Asia Maritime Southeast Asia comprises the countries of Brunei, Indonesia, Malaysia, the Philippines, Singapore, and East Timor. Maritime Southeast Asia is sometimes also referred to as Island Southeast Asia, Insular Southeast Asia or Oceanic Sout ...

Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologica ...

, America,

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

St. Helena Saint Helena () is a British overseas territory located in the South Atlantic Ocean. It is a remote volcanic tropical island west of the coast of south-western Africa, and east of Rio de Janeiro in South America. It is one of three constit ...

, about 25 species) *'' Cystodium'' (Island Southeast Asia, 1 species) *''

'' (

Juan Fernández Islands The Juan Fernández Islands ( es, Archipiélago Juan Fernández) are a sparsely inhabited series of islands in the South Pacific Ocean reliant on tourism and fishing. Situated off the coast of Chile, they are composed of three main volcanic i ...

, 1 species) *'' Culcita'' (tropical America,

Macaronesia Macaronesia (Portuguese: ''Macaronésia,'' Spanish: ''Macaronesia'') is a collection of four volcanic archipelagos in the North Atlantic, off the coasts of Africa and Europe. Each archipelago is made up of a number of List of islands in the At ...

Iberian Peninsula The Iberian Peninsula (), ** * Aragonese and Occitan: ''Peninsula Iberica'' ** ** * french: Péninsule Ibérique * mwl, Península Eibérica * eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, defi ...

, 2 species) *''

Cibotium ''Cibotium'' (from Greek , ''kibṓtion'', "little chest" or "box"), also known as manfern, is a genus of 11 species of tropical tree ferns. It is the only genus in family Cibotiaceae in the Pteridophyte Phylogeny Group classification of 2016 (PP ...

'' (Southeast Asia, Hawaii,

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

, about 12 species)

References

{{reflist

External links

Flora Technical Note No. 5: Identification and management of tree ferns
from Tasmania Forest Practices Authority
Tree Fern
from the San Diego Zoo website Ferns Plant common names Plants by habit