''Osmunda'' 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 primarily temperate-zone

fern The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

s of

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Osmundaceae. Five to ten

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

have been listed for this genus. They have existed since the Early Cretaceous.

Description

Completely dimorphic

frond A frond is a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group. Other botanists allow the term frond to also apply to the lar ...

s or pinnae (hemidimorphic), green

photosynthetic Photosynthesis ( ) is a Biological system, system of biological processes by which Photoautotrophism, photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical ener ...

sterile fronds, and non-photosynthetic

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

-bearing fertile pinnae, with large, naked

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 ...

. Because of the large mass of

that ripen uniformly at the same time to a showy golden color, the ferns look as if they are in flower, and so this genus is sometimes called the "flowering ferns".

Taxonomy

''Osmunda'', the

type genus In biological taxonomy, the type genus (''genus typica'') is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearin ...

of the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Osmundales Osmundaceae (royal fern family) 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 or ...

has historically been the largest genus in the family Osmundaceae. Smith et al. (2006), who carried out the first higher-level

pteridophyte A pteridophyte is a vascular plant (with xylem and phloem) 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 ...

classification published in the

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

era, described three genera in that family, namely ''Osmunda'', '' Leptopteris'', and '' Todea''. The genus has also been treated historically as consisting of a number of subgroups, generally subgenera, ''Osmunda'' (3 species), ''Osmundastrum'' (2 species), and ''Plenasium'' (3–4 species). However, there was suspicion that the genus was not

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

. The publication of a detailed

phylogeny A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or Taxon, taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, M ...

of the family by Metzgar et al. in 2008 showed that ''Osmunda'' as circumscribed was

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

and that ''

Osmunda cinnamomea ''Osmundastrum'' is genus of leptosporangiate ferns in the family Osmundaceae with one living species, ''Osmundastrum cinnamomeum'', the cinnamon fern. It is native to the Americas and eastern Asia, growing in swamps, bogs and moist woodlands. ...

'', despite its morphological similarity to '' Osmunda claytoniana'', was

sister A sister is a woman or a girl who shares parents or a parent with another individual; a female sibling. The male counterpart is a brother. Although the term typically refers to a familial relationship, it is sometimes used endearingly to ref ...

to the rest of the family, and resurrected the segregate genus ''Osmundastrum'', by elevating it from subgenus, to contain it and render ''Osmunda''

. The phylogeny of ''Osmunda'' is shown in the following cladograms. A number of authors have proposed elevating the subgenera to separate genus level, In 2016 the Pteridophyte Phylogeny Group (PPG) classification split ''Osmunda'' further by elevating its subgenera to genera as ''Claytosmunda'' and ''Plenasium'', leaving only the species originally included in subgenus ''Osmunda''. *'' O. abyssinica'' (Kuhn 1879) Bobrov *'' O. acuta'' (Burm.fil. 1768) Fraser-Jenk. *'' O. chengii'' Bomfleur, Grimm & McLoughlin 'Osmunda claytoniites'' Phipps, Taylor & Taylor non Graham 1963">Osmunda_claytoniites.html" ;"title="'Osmunda claytoniites">'Osmunda claytoniites'' Phipps, Taylor & Taylor non Graham 1963ref>Thomas N. Taylor, Edith L. Taylor, Michael Krings: Paleobotany. The Biology and Evolution of Fossil Plants . Second Edition, Academic Press 2009, , p. 437-443 *'' O. herbacea'' Copeland *'' O. hybrida'' Tsutsumi et al. *'' O. × intermedia'' *'' O. japonica'' Thunberg (Japanese flowering fern) *'' O. lancea'' Thunberg (Japanese lancea flowering fern) *'' O. x mildei'' *'' O. piresii'' Brade 1965 *'' O. regalis'' L. (Old World royal fern) *'' O. × ruggii'' *''Osmunda spectabilis">O. spectabilis'' Willdenow (American royal fern) *''Osmunda wehrii">O. wehrii'' Miller (Middle Miocene, Washington state)

Etymology

The derivation of the genus name is uncertain. A common theory is that ''Osmunda'' derives from ''Osmunder'', a Saxon name for the god Thor. Other explanations propose that it is from Middle English and Middle French words for a type of fern, or mention an English folk tale of a boatman named Osmund hiding his wife and children in a patch of royal fern during the Danish invasion.

Ecology

''Osmunda'' species are used as food plants by the

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e of some

Lepidoptera Lepidoptera ( ) or lepidopterans is an order (biology), order of winged insects which includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organ ...

species including the engrailed. One of the species, the

cinnamon fern ''Osmundastrum'' is genus of leptosporangiate ferns in the family Osmundaceae with one living species, ''Osmundastrum cinnamomeum'', the cinnamon fern. It is native to the Americas and eastern Asia, growing in swamps, bogs and moist woodlands. ...

(''Osmundastrum cinnamomeum'') forms huge clonal colonies in

swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

areas. These ferns form massive rootstocks with densely matted, wiry roots. This root mass is an excellent substrate for many epiphytal plants. They are often harvested as osmundine and used horticulturally, especially in propagating and growing

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Orchids are cosmopolitan plants that are found in almost every habitat on Eart ...

References

Bibliography

* * * * * * * * * * * * , in * Phipps, C.J., Taylor, T.N., Taylor, E.L., Cuneo, N.R., Boucher, L.D., and Yao, X. (1998). ''Osmunda'' (Osmundaceae) from the Triassic of Antarctica: An example of evolutionary stasis. American Journal of Botany 85: 888-895

External links

Germplasm Resources Information Network: ''Osmunda''Flora of North America: ''Osmunda''
*http://data.gbif.org/species/browse/taxon/13191108 {{Taxonbar, from=Q1427328 Osmundales Extant Triassic first appearances Fern genera Taxa named by Carl Linnaeus