Osmunda
Encyclopedia
Osmunda is a genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of primarily temperate-zone fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...

s of family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Osmundaceae
Osmundaceae
The Osmundaceae is a family of four genera and 15-25 species. It is the only fern family of the order Osmundales; an order in the class Pteridopsida or in some classifications the only order in the class Osmundopsida...

. Five to ten species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 have been listed for this genus.

The species have completely dimorphic frond
Frond
The term frond refers to 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...

s or pinna
Pinna
In animal anatomy, the pinna is the visible part of the ear that resides outside of the head ....

e (hemidimorphic), green photosynthetic
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...

 sterile fronds, and non-photosynthetic spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

-bearing fertile pinnae, with large, naked sporangia
Sporangium
A sporangium is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. All plants, fungi, and many other lineages form sporangia at some point in their life cycle...

. Because of the large mass of sporangia 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".

The genus is known in the fossil record back to the Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

 period from fragmentary foliage nearly identical to the living Osmunda claytoniana.

Section Osmunda (Euosmunda)

  • Osmunda japonica – Japanese flowering fern
  • Osmunda lancea
    Osmunda lancea
    Osmunda lancea is a fern in the genus Osmunda, section Euosmunda. It is found in Japan.It often hybridizes with Osmunda japonica to produce O. × intermedia.-External Links:***...

    -- Japanese lancea flowering fern
  • Osmunda regalis – Old World royal fern
  • Osmunda spectabilis
    Osmunda spectabilis
    Osmunda spectabilis is a species of fern once thought to be the same as Osmunda regalis, but recent genetic studies have shown it to be a separate species. -Description:...

    - American royal fernOsmunda wehrii
    Osmunda wehrii
    Osmunda wehrii is an extinct species of fern in the modern Osmundaceae family genus Osmunda. Osmunda wehrii is known from Langhian age Miocene fossils found in Central Washington.-History and classification:...

    - Miller (Middle Miocene, Washington state)

Section Plenasium

  • Osmunda angustifolia
    Osmunda angustifolia
    Osmunda angustifolia is a fern in the genus Osmunda, section Plenasium. It can be found growing in East Asia.-References:***...

  • Osmunda banksiifolia
    Osmunda banksiifolia
    Osmunda banksiifolia is a fern in the genus Osmunda, section Plenasium. It is found in Kamchatka, Japan, Taiwan, the Philippines, China and the Ryukyu islands.-References:*...

  • Osmunda bromeliifolia
    Osmunda bromeliifolia
    Osmunda bromeliifolia is a fern in the genus Osmunda, section Plenasium.It can be found in the Philippines....

  • Osmunda javanica
    Osmunda javanica
    Osmunda javanica is a fern in the genus Osmunda, section Plenasium....

  • Osmunda vachellii
    Osmunda vachellii
    Osmunda vachellii is a species of fern in the genus Osmunda, section Plenasium....


Section Claytosmunda

  • Osmunda claytoniana – interrupted fern, Clayton's fern
  • Osmunda claytoniites
    Osmunda claytoniites
    Osmunda claytoniites is an extinct fern in the genus Osmunda, very similar to the extant fern Osmunda claytoniana. It has been found in the Upper Triassic of Antarctica....

    (Phipps et al., 1998)

Hybrids

  • Osmunda × ruggii
    Osmunda × ruggii
    Osmunda × ruggii is a sterile hybrid between Osmunda claytoniana and Osmunda spectabilis.-References:*...

    : O. claytoniana × O. spectabilis
    Osmunda spectabilis
    Osmunda spectabilis is a species of fern once thought to be the same as Osmunda regalis, but recent genetic studies have shown it to be a separate species. -Description:...

  • Osmunda × intermedia
    Osmunda × intermedia
    Osmunda × intermedia is a semifertile hybrid between Osmunda japonica and Osmunda lancea....

    : O. lancea
    Osmunda lancea
    Osmunda lancea is a fern in the genus Osmunda, section Euosmunda. It is found in Japan.It often hybridizes with Osmunda japonica to produce O. × intermedia.-External Links:***...

    × O. japonica
  • Osmunda mildei
    Osmunda mildei
    Osmunda mildei is a rare fern, known only from a few locations in the area of Hong Kong. It is also a rarity in that it appears to be a species of hybrid origin within the Osmundaceae. Its putative parents are Osmunda angustifolia and O...

    : apparently a species, but arising from O. angustifolia
    Osmunda angustifolia
    Osmunda angustifolia is a fern in the genus Osmunda, section Plenasium. It can be found growing in East Asia.-References:***...

    × O. japonica

Osmundastrum

The following species actually belong in the separate genus Osmundastrum, even though they have long been regarded as part of Osmunda:
  • Osmundastrum asiaticum (syn. Osmunda cinnamomea var. asiatica) – Asian Cinnamon Fern
  • Osmundastrum cinnamomeum – Cinnamon Fern

Characteristics

Osmunda species are used as food plants by the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e of some Lepidoptera
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...

 species including The Engrailed
Engrailed
The Engrailed and Small Engrailed are moths of the family Geometridae. They are distributed across most of Europe. There is an on-going debate as to whether they make up one species, or whether E. crepuscularia actually refers only to the Small Engrailed, with the Engrailed proper being separable...

.

One of the species, the Cinnamon fern
Cinnamon fern
Osmundastrum cinnamomeum, the Cinnamon Fern, is a species of eusporangiate fern in the family Osmundaceae. It is native to the Americas and eastern Asia, growing in swamps, bogs and moist woodlands....

 (Osmundastrum cinnamomeum) forms huge clonal colonies in swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...

 areas. These ferns form massive rootstocks with densely-matted, wiry roots. This root mass is an excellent substrate for many epiphytal
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...

 plants. They are often harvested as osmundine and used horticulturally
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...

, especially in propagating and growing orchids.

The derivation of the genus name is uncertain. A leading theory is that it is from an English folk tale of a boatman named Osmund hiding his wife and children in a patch of royal fern during the Danish invasion. Other theories propose that it is from Middle English
Middle English
Middle English is the stage in the history of the English language during the High and Late Middle Ages, or roughly during the four centuries between the late 11th and the late 15th century....

 and Middle French
Middle French
Middle French is a historical division of the French language that covers the period from 1340 to 1611. It is a period of transition during which:...

words for a type of fern.


























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