''Didymoglossum'' is a tropical

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 in the family

Hymenophyllaceae The Hymenophyllaceae, the filmy ferns and bristle ferns, are a family of two to nine genera (depending on classification system) and about 650 known species of ferns, with a subcosmopolitan distribution, but generally restricted to very damp pla ...

. It comprises more than 30

epilithic Lithophytes are plants that grow in or on rocks. They can be classified as either epilithic (or epipetric) or endolithic; epilithic lithophytes grow on the surfaces of rocks, while endolithic lithophytes grow in the crevices of rocks (and are also ...

or low-

epiphytic An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...

species under two subgenera.Ebihara et al.: A Taxonomic Revision of Hymenophyllaceae
Blumea - Biodiversity, Evolution and Biogeography of Plants, Volume 51, Number 2, July 2006 , pp. 221-280(60) The genus is accepted in the

Pteridophyte Phylogeny Group The Pteridophyte Phylogeny Group, or PPG, is an informal international group of systematic botanists who collaborate to establish a consensus on the classification of pteridophytes (lycophytes and ferns) that reflects knowledge about plant relation ...

classification of 2016 (PPG I), but not by some other sources which sink it into a broadly defined ''

Trichomanes ''Trichomanes'' is a genus of ferns in the family Hymenophyllaceae, termed bristle ferns. The circumscription of the genus is disputed. All ferns in the genus are filmy ferns, with leaf tissue typically 2 cells thick. This thinness generally nec ...

''.

Taxonomy

The genus ''Didymoglossum'' was first described by

Nicaise Auguste Desvaux Nicaise Auguste Desvaux (28 August 1784 – 12 July 1856) was a French botanist. From 1816 he taught classes in Angers, where from 1817 to 1838 he served as director of its botanical garden. He described the botanical genera ''Neslia'', ''Mycenast ...

in 1827. Its status, like other genera in the subfamily

Trichomanoideae The Hymenophyllaceae, the filmy ferns and bristle ferns, are a family of two to nine genera (depending on classification system) and about 650 known species of ferns, with a subcosmopolitan distribution, but generally restricted to very damp pla ...

, remains disputed. The

classification of 2016 (PPG I) accepts the genus, placing it in the subfamily

Hymenophylloideae ''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 fern ...

and saying that there are about 30 species. , the ''Checklist of Ferns and Lycophytes of the World'' listed 55 species, whereas ''

Plants of the World Online Plants of the World Online (POWO) is an online database published by the Royal Botanic Gardens, Kew. It was launched in March 2017 with the ultimate aim being "to enable users to access information on all the world's known seed-bearing plants by ...

'' sank the genus into ''

''.

Subgenera and species

Subgenus ''Didymoglossum''

Subgenus is mainly

neotropical The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In bioge ...

, with about 20 species, which include:

Subgenus ''Microgonium''

Subgenus is mainly

paleotropical The Paleotropical Kingdom (Paleotropis) is a floristic kingdom comprising tropical areas of Africa, Asia and Oceania (excluding Australia and New Zealand), as proposed by Ronald Good and Armen Takhtajan. Part of its flora, inherited from the ancient ...

with more than 10 species, which include:

References

{{Taxonbar, from=Q2255950 Hymenophyllales Fern genera