| Alsophila | |
|---|---|
 | |
| Alsophila capensis | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Division: | Polypodiophyta |
| Class: | Polypodiopsida |
| Order: | Cyatheales |
| Family: | Cyatheaceae |
| Genus: | Alsophila R.Br. [1] |
| Synonyms [2] | |
Dicranophlebia(Mart.) Lindl. (1846) | |
Alsophila is a genus of tree ferns in the family Cyatheaceae. [1] It has also been considered to be a section in the subgenus Cyathea of the genus Cyathea.
Species of Alsophila have a treelike growth habit, with an erect trunk that rarely branches, or sometimes a more shrublike habit, with a creeping stem. Their fronds are large, with a strawlike stalk (stipe), dark brown or black in colour. Brown or dark brown scales are present, with distinct margins. The blade (lamina) of the frond is divided one to three times (one- to three-pinnate). The sori (spore-producing structures) are rounded and borne on smaller veins on the lower surface of the frond. An indusium (a covering to the sori) may or may not be present; if present initially, it may be lost as the frond ages. [3]
Alsophila is now separated from the other genera in the family Cyatheaceae primarily on the basis of molecular phylogenetic studies. [1] The scales on the stalks (petioles) provide a morphological distinction. Alsophila has scales with distinct margins, unlike Sphaeropteris, and with an apical hair or spine (seta), unlike Cyathea. The ornamentation of the spores also distinguishes Alsophila and Cyathea. [4] [5]
The genus Alsophila was erected by Robert Brown in 1810. [6] It is placed in the family Cyatheaceae. [1] The division of the family into genera has had a long and controversial history. [5] Three or four clades have been suggested based on molecular phylogenetic studies. The Pteridophyte Phylogeny Group classification of 2016 (PPG I) accepts three genera, placing the Gymnosphaera clade within Alsophila. [1] In 2018, Dong and Zuo proposed the relationship shown in the cladogram below, and provided names in Gymnosphaera for species they considered to belong in this genus. [7]
| Cyatheaceae |
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Older sources, such as the New Zealand Organisms Register as of October 2000 [update] and Large and Braggins (2004), place Alsophila within a broadly defined Cyathea. [8] [9]
The Pteridophyte Phylogeny Group classification of 2016 (PPG I) accepted the genus Alsophila with 275 species. [1] As of December 2023 [update] , Plants of the World Online accepted 248 species. [2]
(Partial list)
The genus Alsophila is native in tropical and subtropical areas, from North and South America, through Africa, Madagascar and tropical Asia, to eastern Australasia as far south as the subantarctic Auckland Islands. [2] [3] It is found in moist montane forests, on slopes or in ravines, forming part of the lower canopy, middle understorey, or ground layers. [3]
Alsophila species all require frost-free or virtually frost-free, permanently moist, shaded conditions. Those which have been grown in Europe outside their native habitat include A. australis , A. cunninghamii , A. dealbata , A. leichhardtiana and A. rebeccae . [11] Other species are grown in their native regions. In Australia, A. australis is commonly grown and is a robust species, capable of tolerating some sun if kept in moist soil. [12] A. dregei is a popular garden plant in South Africa, with plants being collected for use from the wild sufficiently often to cause it to become extinct in some areas. [13]
The silver fern, Alsophila dealbata has become a widely recognised symbol of New Zealand, although it is not an official national symbol. [14]
In the 1971 comedy film A New Leaf , Henrietta Lowell (played by Elaine May) is a botanist whose dream is to classify a new species of fern. On a honeymoon trip, she indeed discovers a new species which she names Alsophila grahami after her new husband Henry Graham (Walter Matthau). She describes the plant as having a vestigial indusium.
Pteris (brake) is a genus of about 300 species of ferns in the subfamily Pteridoideae of the family Pteridaceae. They are native to tropical and subtropical regions, southward to New Zealand, Australia, and South Africa, north to Japan and North America. 78 species are found in China. Some species of Pteris have considerable economic and ecological value, such as Pteris multifida, Pteris ensiformis, Pteris vittata can be used for ornamental purposes; as a hyperaccumulator, Pteris multifida and Pteris vittata can be used to control soil pollution.
Cyathea is a genus of tree ferns, the type genus of the fern order Cyatheales.
Microsorum is a genus of ferns in the family Polypodiaceae, subfamily Microsoroideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). The species are tropical. Like most ferns, they grow from rhizomes, rather than roots. The genus name is often misspelled "Microsorium" or "Microsoreum". It includes some species that are lithophytic rheophytes.
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.
Gymnosphaera biformis, synonyms Alsophila biformis and Cyathea biformis, is a species of tree fern native to New Guinea and the Maluku Islands, where it grows against trees in mossy forest and rain forest at elevations of 850–2200 m. The climbing trunk is very thin, only 1–2 cm in diameter, but can reach 3 m in height. The apex of the trunk is covered in scales. Two types of fronds are produced, simple pinnate fronds, which are sterile, and bipinnate fronds, which may be fertile. The stipe is smooth, glossy and very dark, almost to the point of being black. It is covered at the base with long, very dark scales that have a pale margin. Fertile pinnules are distinctly stalked and lobed. Sori occur in four pairs per pinnule lobe and lack indusia.
Gymnosphaera is a genus of tree ferns in family Cyatheaceae.
Dennstaedtia is a mostly tropical and subtropical genus of ferns described as a genus in 1801. hayscented fern, or cup ferns, are common names for some species in this genus. Its best-known member is probably the temperate North-American hay-scented fern, Dennstaedtia punctilobula, which forms extensive clonal ground-cover colonies on level surfaces in the Appalachian area.
Bolbitis is a genus of ferns in the family Dryopteridaceae, subfamily Elaphoglossoideae, in the Pteridophyte Phylogeny Group classification of 2016.
Hymenophyllum is a genus of ferns in the family Hymenophyllaceae. Its name means "membranous leaf", referring to the very thin translucent tissue of the fronds, which gives rise to the common name filmy fern for this and other thin-leaved ferns. The leaves are generally only one cell thick and lack stomata, making them vulnerable to desiccation. Consequently, they are found only in very humid areas, such as in moist forests and among sheltered rocks. They are small and easy to overlook.
Saccoloma is a fern genus in family Saccolomataceae. It is the only genus in the family in the Pteridophyte Phylogeny Group classification of 2016, but further investigation is needed. It is pantropical and its species are found in wet, shaded forest areas. Saccoloma species are characterized by an omega-shaped (Ω) vascular bundle in the cross-sections of their petioles. The common name soralpouch fern is used for Saccoloma.
Tectaria is a genus of fern in the family Tectariaceae, according to the Pteridophyte Phylogeny Group classification of 2016. Halberd fern is a common name for species in this genus.
Deparia is a genus of ferns. The Pteridophyte Phylogeny Group classification of 2016 places the genus in the family Athyriaceae, although other sources include it within an expanded Aspleniaceae or Woodsiaceae.
Lindsaea, common name necklace fern, is a genus of around 180 species of fern, 15 of which reach Australia. The name is in honour of surgeon John Lindsay of Jamaica. The genus is sometimes spelt Lindsaya.
Christella is a genus of around 70-80 species of ferns in the subfamily Thelypteridoideae of the family Thelypteridaceae in the Pteridophyte Phylogeny Group classification of 2016. Other sources sink Christella into a very broadly defined genus Thelypteris. The genus was named after Konrad H. Christ, a Swiss botanist. The distribution of these plants is mostly in the tropics and sub tropical areas. An Australian example is C. dentata.
Pronephrium is a genus of ferns in the family Thelypteridaceae in the family Thelypteridaceae, subfamily Thelypteridoideae, in the Pteridophyte Phylogeny Group classification of 2016. Other sources sink Pronephrium into a very broadly defined genus Thelypteris. Some species were split off into the genera Abacopteris, Grypothrix and Menisciopsis in 2021 as a result of a phylogenetic study of the family Thelypteridaceae.
Amauropelta is a genus of ferns in the family Thelypteridaceae, subfamily Thelypteridoideae, in the Pteridophyte Phylogeny Group classification of 2016. Other sources sink the genus into a very broadly defined genus Thelypteris.
Coryphopteris is a genus of ferns in the family Thelypteridaceae, subfamily Thelypteridoideae, in the Pteridophyte Phylogeny Group classification of 2016.