Cyatheales

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Tree fern (Cyatheales)
Temporal range: Late Jurassic–Recent
Dicksonia antarctica in Nunniong, Australia.jpg
Dicksonia antarctica
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Subclass: Polypodiidae
Order: Cyatheales
A.B.Frank
Families

Note: These families are alternatively treated as subfamilies of the single family Cyatheaceae [1]

Contents

The order Cyatheales, which includes most tree ferns, is a taxonomic order of the fern class, Polypodiopsida. [2] No clear morphological features characterize all of the Cyatheales, but DNA sequence data indicate the order is monophyletic. Some species in the Cyatheales have tree-like growth forms from a vertical rhizome, others have shorter or horizontal expanding rhizomes.

Some species have scales on the stems and leaves, while others have hairs. However, most plants in the Cyatheales are tree ferns and have trunk-like stems up to 10 metres (33 ft) tall. It is unclear how many times the tree form has evolved and been lost in the order. [3]

Description

While the Cyatheales have been shown to be monophyletic through molecular analysis, no prominent morphological characteristics are common to the entire group. [4] Though loosely referred to as "tree ferns", most but not all members of the order possess the characteristic tree fern morphology: the rhizome is massive, woody, and rather than creeping horizontally below or on the ground, it stands erect and above ground, like a tree trunk, bearing a crown of fronds. This habit is most evident in families Dicksoniaceae and Cyatheaceae. Outside of the Cyatheales, a few ferns in other groups could be considered tree ferns, such as several ferns ( Leptopteris and Todea ) in the family Osmundaceae that can achieve short trunks under 1 metre (3.3 ft) tall. A few species in the genera Blechnum and Sadleria could also be considered tree ferns in a liberal interpretation of the term.

Like all ferns, tree ferns reproduce by means of spores developed in sporangia on the undersides of the fronds.

Dicksonia antarctica at Kew Dicksonia antarctica 20 - Kew Gardens.jpg
Dicksonia antarctica at Kew

The fronds of tree ferns are usually very large and multiple-pinnated, but at least one type has entire (undivided) fronds. The fronds of tree ferns also exhibit circinate vernation, meaning the young fronds emerge in coils that uncurl as they grow.

Unlike flowering plants, tree ferns do not form new woody tissue in their trunk as they grow. Rather, the trunk is supported by a fibrous mass of roots that expands as the tree fern grows.

Some genera for example Dicksonia and Cibotium , and some Cyathea can be transplanted by severing the top portion from the rest of the trunk and replanting it. If the transplanted top part is kept moist it will regrow a new root system over the next year. The success rate of transplantation increases if the roots are dug up intact. If the crown of the Tasmanian tree fern Dicksonia antarctica (the most common species in gardens) is damaged, it will die because all new growth occurs there. 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 reroot from this new prostrate position and begin new vertical growth.

Tree fern frond ("fiddlehead") by the Akatarawa River, New Zealand. Tree fern frond at Akatarawa.jpg
Tree fern frond ("fiddlehead") by the Akatarawa River, New Zealand.

The number of tree fern species is likely to be around a thousand. Although new species are discovered in New Guinea with each botanical survey, many species throughout its range have become extinct in the last century as forest habitats have come under pressure from human activities.

Transplanted Dicksonia antarctica tree ferns at Combe Martin Wildlife and Dinosaur Park, Devon, England Nzfern.arp.500pix.jpg
Transplanted Dicksonia antarctica tree ferns at Combe Martin Wildlife and Dinosaur Park, Devon, England

Taxonomy

In the molecular phylogenetic classification of Smith et al. in 2006, the Cyatheales were placed in the leptosporangiate ferns, class Polypodiopsida. Eight families, Thyrsopteridaceae, Loxsomataceae, Culcitaceae, Plagiogyriaceae, Cibotiaceae, Cyatheaceae, Dicksoniaceae, and Metaxyaceae, were recognized. [5] The linear sequence of Christenhusz et al. (2011), intended for compatibility with the classification of Chase and Reveal (2009) [6] which placed all land plants in Equisetopsida, [7] reclassified Smith's Polypodiopsida as subclass Polypodiidae and placed the Cyatheales there. The circumscription of the order and its families was not changed. [6] The classification of Christenhusz and Chase (2014) placed all members of the Cyatheales in a more broadly defined Cyatheaeaceae, reducing the eight existing families to subfamilies as Thyrsopteridoideae, Loxsomatoideae, Culcitoideae, Plagiogyrioideae, Cibotioideae, Cyatheoideae, Dicksonioideae, and Metaxyoideae. [1] The PPG I classification (2016) returned to the eight-family definition of the order., [8] but this is not yet accepted by the general botanical community.

Historically, the Plagiogyriaceae were considered the single member of order Plagiogyriales, thought to be more closely related to Osmundales than to the tree ferns, but this hypothesis has been disproven by molecular phylogenetics.

Cyathea medullaris can grow up to 20 m tall in its native New Zealand. Cyathea-med2.jpg
Cyathea medullaris can grow up to 20 m tall in its native New Zealand.
Koral 2006, Koral 2007 & Lehtonen 2011 [2] [9] [10] Nitta et al. 2022 [11] and Fern Tree of life [12]
Cyatheales

Incertae sedis fossil genera

Distribution and habitat

Tree ferns are found growing in tropical and subtropical areas, as well as temperate rainforests in South Africa, Australia, Spain, Portugal, New Zealand, and other island groups nearby; a few genera extend further, such as Culcita in southern Europe.

While many ferns are able to achieve a widespread distribution because of their spore reproduction, tree fern species tend to be very local. This makes their species much more susceptible to the effects of local deforestation. Why species are not more widespread is unknown, especially considering they have sufficient height to have a greater chance of getting spores into the wind stream.[ citation needed ]

Conservation

Where feral pigs are a problem, as in some Hawaiian rainforests, they will knock over tree ferns to root out the starchy pith, killing the plant. [13]

A lone tree fern next to the Peak Tram line on Hong Kong Island Fern Tree next to the Peak Tram road.jpg
A lone tree fern next to the Peak Tram line on Hong Kong Island

Related Research Articles

<span class="mw-page-title-main">Osmundaceae</span> Family of ferns

Osmundaceae 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 order in the class Osmundopsida. This is an ancient and fairly isolated group that is often known as the "flowering ferns" because of the striking aspect of the ripe sporangia in Claytosmunda, Osmunda, Osmundastrum, and Plensium. In these genera the sporangia are borne naked on non-laminar pinnules, while Todea and Leptopteris bear sporangia naked on laminar pinnules. Ferns in this family are larger than most other ferns.

<span class="mw-page-title-main">Schizaeales</span> Order of ferns

Schizaeales is an order of ferns.

<i>Osmunda</i> Genus of ferns

Osmunda is a genus of primarily temperate-zone ferns of family Osmundaceae. Five to ten species have been listed for this genus.

<span class="mw-page-title-main">Salviniales</span> Order of plants

The order Salviniales is an order of ferns in the class Polypodiopsida.

<span class="mw-page-title-main">Marattiaceae</span> Family of ferns

Marattiaceae is the only family of extant (living) ferns in the order Marattiales. In the Pteridophyte Phylogeny Group classification of 2016, Marattiales is the only order in the subclass Marattiidae. The family has six genera and about 110 species. Many are different in appearance from other ferns, having large fronds and fleshy rootstocks.

<span class="mw-page-title-main">Gleicheniales</span> Order of ferns

Gleicheniales is an order of ferns in the subclass Polypodiidae. The Gleicheniales have records potentially as early as the Carboniferous, but the oldest unambiguous records date to the Permian.

<span class="mw-page-title-main">Dryopteridaceae</span> Family of ferns

The Dryopteridaceae are a family of leptosporangiate ferns in the order Polypodiales. They are known colloquially as the wood ferns. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family is placed in the suborder Polypodiineae. Alternatively, it may be treated as the subfamily Dryopteridoideae of a very broadly defined family Polypodiaceae sensu lato.

<span class="mw-page-title-main">Polypodiales</span> Order of ferns

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.

<span class="mw-page-title-main">Pteridophyte</span> Group of plants that reproduce by spores

A pteridophyte is a vascular plant that reproduces by means of spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as "cryptogams", meaning that their means of reproduction is hidden.

<span class="mw-page-title-main">Psilotaceae</span> Family of ferns

Psilotaceae is a family of ferns consisting of two genera, Psilotum and Tmesipteris with about a dozen species. It is the only family in the order Psilotales.

<span class="mw-page-title-main">Cyatheaceae</span> Family of ferns

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. Alternatively, the family may defined much more broadly as the only family in the Cyatheales, with the PPG I family treated as the subfamily Cyatheoideae. The narrower circumscription is used in this article.

<span class="mw-page-title-main">Dicksoniaceae</span> Family of ferns

Dicksoniaceae is a group of tropical, subtropical and warm temperate ferns, treated as a family in the Pteridophyte Phylogeny Group classification of 2016, and counting 30-40 species. Alternatively, the family may be sunk into a very broadly defined family Cyatheaceae sensu lato as the subfamily Dicksonioideae. Most of the genera in the family are terrestrial ferns or have very short trunks compared to tree ferns of the family Cyatheaceae sensu stricto. However, some of the larger species can reach several metres in height. A number of others are epiphytes. They are found mostly in tropical regions in the Southern Hemisphere, as far south as southern New Zealand. Larger tree ferns in the genus Cibotium were formerly included in Dicksoniaceae, but are now segregated as the family Cibotiaceae.

<span class="mw-page-title-main">Pteridaceae</span> Family of ferns

Pteridaceae is a family of ferns in the order Polypodiales, including some 1150 known species in ca 45 genera, divided over five subfamilies. The family includes four groups of genera that are sometimes recognized as separate families: the adiantoid, cheilanthoid, pteridoid, and hemionitidoid ferns. Relationships among these groups remain unclear, and although some recent genetic analyses of the Pteridales suggest that neither the family Pteridaceae nor the major groups within it are all monophyletic, as yet these analyses are insufficiently comprehensive and robust to provide good support for a revision of the order at the family level.

<span class="mw-page-title-main">Leptosporangiate fern</span> Subclass of ferns

The Polypodiidae, commonly called leptosporangiate ferns, formerly Leptosporangiatae, are one of four subclasses of ferns, the largest of these being the largest group of living ferns, including some 11,000 species worldwide. The group has also been treated as the class Pteridopsida or Polypodiopsida, although other classifications assign them a different rank. Older names for the group include Filicidae and Filicales, although at least the "water ferns" were then treated separately.

<i>Sadleria cyatheoides</i> Species of plant

Sadleria cyatheoides, commonly known as amaumau fern or ʻamaʻu, is a fern species in the family Blechnaceae, in the eupolypods II clade of the order Polypodiales, in the class Polypodiopsida. It is endemic to Hawaii and inhabits lava flows, open areas, and wet forests on all major islands up to an altitude of 1,676 m (5,499 ft). Reaching a height of 0.9–1.5 m (3.0–4.9 ft) and a trunk diameter of 7.5–10 cm (3.0–3.9 in), ʻamaʻu resembles a small tree fern. Kīlauea's Halemaʻumaʻu is named for this species.

<span class="mw-page-title-main">Saccolomataceae</span> Family of ferns

Saccolomataceae is a family of ferns in the order Polypodiales with about 19 species. It has been formerly treated as part of the Dennstaedtiaceae, however it has been classified as its own family according to Smith et al. (2006) The genus Saccoloma has been classified to include Orthiopteris, but the phylogeny of the group not yet fully understood. The family includes a dozen known species.

<i>Lophosoria quadripinnata</i> Species of fern

Lophosoria quadripinnata(J.F.Gmel.) C.Chr. is a species of fern that, according to DNA molecular analysis, belongs to the family Dicksoniaceae, where it is placed in the genus Lophosoria. It is found in the Americas spanning from Cuba and Mexico to Chile. In Chile it is present in the area between Talca and Aysén including Juan Fernández Islands. In Argentina it grows only in the humid valleys of western Neuquén and Río Negro Province. Diamondleaf fern is a common name. In Spanish it is known as 'ampe' or palmilla, but one has to remember that there are several species of ferns called "palmillas" that have larger or smaller fronds, and which grow in colder climates. It is a medium-sized plant, growing to about 4–5 feet and even though the rhizome does not grow a trunk, it is clearly related to the other tree ferns due to features that were apparently already present in their common ancestor, like 'pneumathodes', and the rhizome which changed from the dorsiventral symmetry typical of the other ferns, to a radial symmetry typical of tree ferns. Their large and multiple pinnate fronds, with the petiole raised adaxially, and the hairs on the rhizome and lower part of the petioles, also resemble those of tree ferns. To identify the species, use the position and characteristics of the spores found on the fertile fronds. The genus already existed in the Cretaceous Period in southern Gondwana according to fossil remains found in Antarctica. The species is well known as an ornamental plant.

<span class="mw-page-title-main">Tectariaceae</span> Family of ferns

Tectariaceae is a family of leptosporangiate ferns in the order Polypodiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family is placed in the suborder Polypodiineae. Alternatively, it may be treated as the subfamily Tectarioideae of a very broadly defined family Polypodiaceae sensu lato. The family comprises seven genera, of which Tectaria is by far the largest.

<span class="mw-page-title-main">Ophioglossidae</span> Subclass of ferns

Ophioglossidae is one of the four subclasses of Polypodiopsida (ferns). This subclass consists of the ferns commonly known as whisk ferns, grape ferns, adder's-tongues and moonworts. It is equivalent to the class Psilotopsida in previous treatments, including Smith et al. (2006). The subclass contains two orders, Psilotales and Ophioglossales, whose relationship was only confirmed by molecular phylogenetic studies.

<span class="mw-page-title-main">Lindsaeineae</span> Suborder of ferns

Lindsaeineae is a suborder of ferns (Polypodiopsida), order Polypodiales, created by the Pteridophyte Phylogeny Group (2016). It consists of two monogeneric families plus the larger Lindsaeaceae with seven genera, and the suborder contains about 237 species overall. It corresponds to Lindsaeaceae sensu Smith 2016.

References

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