Glade fern | |
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Homalosorus pycnocarpos in mesophytic forest, Brown County State Park, Indiana, USA. | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Division: | Polypodiophyta |
Class: | Polypodiopsida |
Order: | Polypodiales |
Suborder: | Aspleniineae |
Family: | Diplaziopsidaceae |
Genus: | Homalosorus Small ex Pic.Serm. |
Species: | H. pycnocarpos |
Binomial name | |
Homalosorus pycnocarpos (Spreng.) Pic.Serm. | |
Synonyms [2] | |
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Homalosorus is a genus of fern with only one species, Homalosorus pycnocarpos. It may also be referred to by its older synonyms Athyrium pycnocarpon and Diplazium pycnocarpon. [2] Commonly referred to as the narrow-leaved glade fern, narrow-leaved-spleenwort, or glade fern, [4] it is endemic to eastern North America and typically grows in moist woodlands. Once classified in the family Athyriaceae due to its linear, often doubled sori, in the Pteridophyte Phylogeny Group classification of 2016 (PPG I), it is placed in the small family Diplaziopsidaceae, whose other three species are native to east Asia. [5] Other sources place the genus in the subfamily Diplaziopsidoideae of a very broadly defined family Aspleniaceae, equivalent to the suborder Aspleniineae in PPG I. [6]
Homalosorus pycnocarpos grows from creeping stems. Its clustered fronds grow to about 90 cm (35 in) long and 15–20 cm (6–8 in) wide. The leaf blade is oblong-lanceolate and once-pinnate. The pinnae are linear and either more-or-less entire or with shallow indentations. The fertile leaves are similar to the sterile leaves, but narrower, with more widely spaced pinnae. The sori are long, straight or slightly curved, borne in two lines along the underside of a leaf pinna. The indusia are thick and prominent. [4] [7] The arrangement of the sori gives rise to its specific epithet pycnocarpos ('crowded fruits'). [7]
The genus Homalosorus was erected by Rudolfo Pichi-Sermolli in 1977. Homalosorus pycnocarpos in its present circumscription was first described by André Michaux in 1803 as Asplenium angustifolium. However, this name was illegitimate, since it had already been used by Nikolaus Joseph von Jacquin in 1786 for a different species of fern. [8] (The description "narrow-leaved" in the English name is a reflection of the original specific epithet: from Latin angustus 'narrow'and folium 'leaf'. [7] ) In 1804, Kurt Sprengler published a description of a species he named Asplenium pycnocarpon. He wrote that he doubted that it was the same as Michaux's Asplenium angustifolium, since that species was described as having smooth-edged leaves. [9] However, later authors have regarded the two as synonymous, [2] [10] so that Asplenium pycnocarpon is the first legitimate name, and hence the basionym of Homalosorus pycnocarpos.
The species has been placed in several genera. It was first described in Asplenium and later transferred to Athyrium . In 1977, Pichi-Sermolli transferred it to the monotypic genus Homalosorus. The Flora of North America placed it in Diplazium as Diplazium pycnocarpon, noting its similarity to the east Asian species then known as Diplazium flavoviride. [4] It was later shown that Diplazium flavoviride and Homalosorus pycnocarpos (as Diplazium pycnocarpon) were closely related to the genus Diplaziopsis . [11]
Molecular phylogenetic studies in 2011, 2012 and 2017 showed that Homalosorus and Diplaziopsis form a clade, with Homalosorus pycnocarpos sister to the species of Diplaziopsis. [12] [13] [14] In 2011, Maarten J. M. Christenhusz and Xuan-Chun Zhang created the family Diplaziopsidaceae, containing both Diplaziopsis and Homalosorus. [15] Diplaziopsidaceae is accepted in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). [5] Other sources place the genus Homalosorus in the subfamily Diplaziopsidoideae of a very broadly defined family Aspleniaceae, equivalent to the suborder Aspleniineae in PPG I. [6]
Homalosorus pycnocarpos is endemic to eastern North America. [2] It is widespread from southern Ontario to the Gulf of Mexico and west to Minnesota and Arkansas. [4] It grows in moist (mesophytic) woods and ravines in neutral or basic soils, at elevations of 150–1,000 m (500–3,300 ft). [4] [7]
Thelypteridaceae is a family of about 900 species of ferns in the order Polypodiales. In the Pteridophyte Phylogeny Group classification of 2016, it is placed in the suborder Aspleniineae. Alternatively, the family may be submerged in a very broadly defined family Aspleniaceae as the subfamily Thelypteridoideae.
The Aspleniaceae (spleenworts) are a family of ferns, included in the order Polypodiales. The composition and classification of the family have been subject to considerable changes. In particular, there is a narrow circumscription, Aspleniaceae s.s., in which the family contains only two genera, and a very broad one, Aspleniaceae s.l., in which the family includes 10 other families kept separate in the narrow circumscription, with the Aspleniaceae s.s. being reduced to the subfamily Asplenioideae. The family has a worldwide distribution, with many species in both temperate and tropical areas. Elongated unpaired sori are an important characteristic of most members of the family.
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.
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.
Oleandra is a genus of ferns. In the Pteridophyte Phylogeny Group classification of 2016, it is the only genus in the family Oleandraceae, which is placed in suborder Polypodiineae, order Polypodiales. Alternatively, the family may be placed in a very broadly defined family Polypodiaceae sensu lato as the subfamily Oleandroideae.
Blechnaceae is a family of ferns in the order Polypodiales, with a cosmopolitan distribution. Its status as a family and the number of genera included have both varied considerably. In the Pteridophyte Phylogeny Group classification of 2016, the family has 24 genera, and excludes genera placed in the separate family Onocleaceae. The family is divided into three subfamilies, including Blechnoideae s.s. Alternatively, the entire family may be treated as the subfamily Blechnoideae s.l. of a very broadly defined family Aspleniaceae, and include genera others place in Onocleaceae.
The Athyriaceae are a family of terrestrial ferns in the order Polypodiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family is placed in the suborder Aspleniineae, and includes two genera. Alternatively, it may be treated as the subfamily Athyrioideae of a very broadly defined family Aspleniaceae. The family has with a cosmopolitan distribution.
Onocleaceae is a small family of terrestrial ferns in the order Polypodiales. It is placed in the suborder Aspleniineae in the Pteridophyte Phylogeny Group classification of 2016. Alternatively, the family, along with Blechnaceae, may be placed in a very broadly defined family Aspleniaceae as the subfamily Blechnoideae. The family may contain from one to four genera, consisting of five species largely in north temperate climes. The four genera, Matteuccia, Onoclea, Onocleopsis and Pentarhizidium, may be included under the single genus Onoclea.
Woodsiaceae is a family of ferns. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), it is placed in the suborder Aspleniineae. The family can also be treated as the subfamily Woodsioideae of a very broadly defined family Aspleniaceae sensu lato. In PPG I, the family contained only one genus, Woodsia. In 2020, Physematium was split off from Woodsia on the basis of molecular phylogenetic evidence. As of June 2023, Plants of the World Online continued to treat Physematium as a synonym of Woodsia.
Aspleniineae is a suborder of ferns in the order Polypodiales. It is equivalent to the clade eupolypods II in earlier systems; it is also treated as a single very broadly defined family Aspleniaceae. The suborder generally corresponds with the order Blechnales as described by J. L. Reveal in 1993. Aspleniineae includes some important ferns, including Onoclea sensibilis, the sensitive fern, which grows as a virtual weed throughout much of its temperate North American range, and ferns of the genus Thelypteris, a genus that has shown remarkable speciation. It also includes one of the more common horticultural ferns, Matteuccia struthiopteris, the ostrich fern.
Asplenium ruprechtii, which goes by the common name Asian walking fern, is a rare, hardy, low-lying fern native to East Asia. It is a close relative of Asplenium rhizophyllum which is found in North America and also goes by the common name of walking fern. The species should not be confused with Asplenium sibiricum which is a synonym of Diplazium sibiricum.
Diplazium is a genus of ferns that specifically includes the approximately 400 known species of twinsorus ferns. The Greek root is diplazein meaning double: the indusia in this genus lie on both sides of the vein. These ferns were earlier considered part of either the Athyriaceae, Dryopteridaceae, Aspleniaceae, or Polypodiaceae families or recognized as belonging to their own taxonomic family. The Pteridophyte Phylogeny Group classification of 2016 places the genus in the Athyriaceae. The taxonomy of the genus is difficult and poorly known, and by 2009 has never been the subject of a complete monographic study. Their distribution is pantropical, with a few species extending into temperate areas.
Cystopteridaceae is a family of ferns in the order Polypodiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family is placed in the suborder Aspleniineae of the order Polypodiales, and includes three genera. Alternatively, it may be treated as the subfamily Cystopteridoideae of a very broadly defined family Aspleniaceae.
Diplazium australe, commonly known as the Austral lady fern, is a small fern occurring in eastern Australia, New Zealand and Norfolk Island. The habitat is moist shaded areas, often occurring in rainforest.
Polypodiineae is a suborder of ferns in the order Polypodiales. It is equivalent to the clade eupolypods I in earlier systems, and to the very broadly defined family Polypodiaceae in the classification of Christenhusz & Chase (2014). It probably diverged from the suborder Aspleniineae during the mid-Cretaceous. The divergence is supported by both molecular data and an often overlooked morphological characteristic which lies in the vasculature of the petiole. Most species that make up the suborder have three vascular bundles. The only exceptions are the grammitid ferns which have one, and the genus Hypodematium which has two. This differs from eupolypods II which mostly have two vascular bundles.
Diplaziopsidaceae is a family of ferns in the order Polypodiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family is placed in the suborder Aspleniineae, and includes two genera. Alternatively, it may be treated as the subfamily Diplaziopsidoideae of a very broadly defined family Aspleniaceae.
Rhachidosorus is a genus of ferns in the order Polypodiales. It is the only genus in the family Rhachidosoraceae in the Pteridophyte Phylogeny Group classification of 2016. Alternatively, the genus may be placed in the subfamily Rhachidosoroideae of a more broadly defined family Aspleniaceae, the family placement used in Plants of the World Online as of November 2019.
Desmophlebium is a genus of ferns. In the Pteridophyte Phylogeny Group classification of 2016, it is the only genus in the family Desmophlebiaceae. Other sources place it in a more widely defined Aspleniaceae.
Hemionitis is a genus of ferns in the subfamily Cheilanthoideae of the family Pteridaceae. Its circumscription varies greatly in different systems of fern classification. In the Pteridophyte Phylogeny Group classification of 2016, it was one of more than 20 genera in the subfamily Cheilanthoideae, and was said to have five species. Other sources treat it as the only genus in the subfamily, and so accept about 450 species. With the restricted circumscription, species are native to tropical America.
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