''Diplazium'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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

classification of 2016 (PPG I) places the genus in the

Athyriaceae The Athyriaceae (ladyferns and allies) 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 gene ...

. 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 A pantropical ("all tropics") distribution is one which covers tropical regions of both the Eastern and Western hemispheres. Examples of species include caecilians, modern sirenians and the plant genera ''Acacia'' and ''Bacopa''. ''Neotropical' ...

, with a few species extending into temperate areas. The

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

of the genus ''Diplazium'' varies from creeping to erect, and is scaly. Its fronds are

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

, are trophopodicThe trophopod is food storage organ described from a number of North American ferns. It consists of the enlarged and modified leaf base filled with starch storage tissue. See W. H. Wagner, Jr. and D. M. Johnson, ''Taxon'', Vol. 32, No. 2 (May, 1983), pp. 268-269 for more information on this organ. and are either monomorphic or weakly dimorphic. The stipe is green, deeply grooved from above, and is either scaly or

glabrous Glabrousness () is the technical term for a lack of hair, down, setae, trichomes, or other such covering. A glabrous surface may be a natural characteristic of all or part of a plant or animal, or be due to loss because of a physical condition, ...

. It always has two

lunate Lunate is a crescent or moon-shaped microlith. In the specialized terminology of lithic reduction, a lunate flake is a small, crescent-shaped lithic flake, flake removed from a stone tool during the process of pressure flaking. In the Natufian cu ...

vascular bundles. The blades are either singular or in sets of two and are entirely

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 ...

, range from oblong-lanceolate to deltate, and from

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of ...

to papery. It has linear basal sori that are paired back-to-back on the same vein. The

indusium A sorus (: sori) is a cluster of sporangia (structures producing and containing spores) in ferns and fungi. A coenosorus (: coenosori) is a compound sorus composed of multiple, fused sori. Etymology This Neo-Latin word is from Ancient Greek � ...

is linear and persistent, and the

sporangia A sporangium (from Late Latin, ; : sporangia) is an enclosure in which spores are formed. It can be composed of a unicellular organism, single cell or can be multicellular organism, multicellular. Virtually all plants, fungus, fungi, and many ot ...

are brownish. Some common species include ''Diplazium hymenodes'', the peacock fern; ''Diplazium esculentum'', the vegetable fern; ''Diplazium molokaiense'', the Molokai twinsorus fern; and ''Diplazium lonchophyllum'', the lance-leaved glade fern.

Taxonomy

''Diplazium'' is in the family

in the

eupolypods II 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 o ...

clade of the order

Polypodiales The Order (biology), 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 Tropics, tropical, semitropical and Temperate clima ...

. The common glade fern of North America, ''Diplazium pycnocarpon'', is found not to belong to that genus, but rather placed in the genus ''

Homalosorus ''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''. Commonly referred to as the narrow-leaved glade fern, ...

'' (

Diplaziopsidaceae 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 treat ...

). Two further species formerly placed in the genus have been transferred to a new genus, ''

Desmophlebium ''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. Taxonomy The family and genus w ...

''.

Selected species

*''

Diplazium australe ''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 Rainforests are forests char ...

'' *''

Diplazium dietrichianum ''Diplazium dietrichianum'' is a small fern occurring in eastern Australia. It occurs in shady damp places.sign at the Royal Botanic Gardens, Sydney. Stating this fern grows from northern New South Wales to tropical Queensland. This plant is from ...

'' *''

Diplazium dilatatum ''Diplazium dilatatum'' is a small fern occurring in India, Indochina, Malesia and Australia as far south as Wauchope, New South Wales. The habitat is moist shaded areas. The type specimen was collected from Burangrang mountain in Java Java ...

'' *''

Diplazium esculentum ''Diplazium esculentum'', the vegetable fern, is an edible fern found throughout Asia and Oceania. It is probably one of the most commonly consumed ferns. The genus '' Diplazium'' is in the family Athyriaceae, in the eupolypods II clade of th ...

'' *''

Diplazium fraxinifolium ''Diplazium fraxinifolium'' is a species of fern in the family Athyriaceae. It is found from India through Malesia to New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of isl ...

'' *'' Diplazium hymenodes'' *'' Diplazium laffanianum'' *'' Diplazium melanochlamys'' *'' Diplazium molokaiense'' *'' Diplazium queenslandicum'' *'' Diplazium sibiricum''

Notes

References

{{Taxonbar, from=Q1802740 Fern genera Pantropical flora Taxa named by Olof Swartz