''Ophioglossum'', the adder's-tongue ferns, is a

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 ...

of about 50 species of ferns in the family

Ophioglossaceae Ophioglossaceae, the adder's-tongue family, is a small family of ferns. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), it is the only family in the order Ophioglossales, which together with the Psilotales is placed in the sub ...

. The name ''Ophioglossum'' comes from the Greek meaning "snake-tongue".eFloras: ''Ophioglossum''
accessed 14 February 2014. Their

cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The ext ...

is mainly in tropical and subtropical

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s. The genus has the largest number of

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...

s in the known plant kingdom, but contrary to popular belief does not have the largest number of chromosomes out of all known organisms, falling short to the protist ''

Sterkiella histriomuscorum ''Sterkiella histriomuscorum'', formerly ''Oxytricha trifallax'', is a ciliate species in the genus '' Sterkiella'', known for its highly fragmented genomes which have been used as a model for ciliate genetics. Genetics Like all ciliates, ''O. ...

''.

Description

Adders-tongues are so-called because the

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

-bearing stalk is thought to resemble a snake's tongue. Each plant typically sends up a small, undivided leaf blade with netted venation, and the spore stalk forks from the leaf stalk, terminating in sporangia which are partially concealed within a structure with slit sides. When the leaf blade is present, there is not always a spore stalk present, and the plants do not always send up a leaf, sometimes going for a year to a period of years living only under the soil, nourished by association with soil

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

. The plant grows from a central, budding, fleshy structure with fleshy, radiating roots.

Taxonomy

''Ophioglossum'' has a high chromosome count in comparison to other species, with 120 or up to 720 chromosomes possible in intervals of 120 due to polyploidy (multiple possible copies of chromosomes). It has almost 1260 number of chromosomes in the meiocyte (spore mother cell) which undergo meiosis, the reduction division to form the spore with only one set of chromosomes getting incorporated into each spore.

Species

, World Ferns listed the following species: *''Goswamia'' **'' Ophioglossum costatum'' **'' Ophioglossum eliminatum'' – status uncertain **'' Ophioglossum gomezianum'' **'' Ophioglossum gujaratensis'' **'' Ophioglossum hitkishorei'' **'' Ophioglossum indicum'' **'' Ophioglossum isanensis'' **''

Ophioglossum malviae ''Ophioglossum malviae'' is a species of fern in the genus ''Ophioglossum'' and found in the forests of Ahwa in the Dang District, India, Dang District of Gujarat. It is claimed to be the world's smallest land fern, with the entire plant growing ...

'' **''

Ophioglossum nudicaule ''Ophioglossum'', the adder's-tongue ferns, is a genus of about 50 species of ferns in the family Ophioglossaceae. The name ''Ophioglossum'' comes from the Greek meaning "snake-tongue".

'' **'' Ophioglossum raphaelianum'' **'' Ophioglossum rubellum'' *''Haukia'' **'' Ophioglossum crotalophoroides'' **'' Ophioglossum opacum'' **''

Ophioglossum tuberosum ''Ophioglossum'', the adder's-tongue ferns, is a genus of about 50 species of ferns in the family Ophioglossaceae. The name ''Ophioglossum'' comes from the Greek meaning "snake-tongue".

'' *''Whittieria'' **''

Ophioglossum engelmannii ''Ophioglossum engelmannii'', commonly known as the limestone adder's-tongue, is a species of fern native to the Western Hemisphere. It is widespread and native to the United States, Mexico, and Central America. Its primary natural habitat is dry ...

'' *''Ophioglossum'' s.s. **'' Ophioglossum ammophilum'' – sometimes included in ''O. gomezianum'' **'' Ophioglossum austroasiaticum'' – possibly a synonym of ''O. reticulatum'' **''

Ophioglossum azoricum ''Ophioglossum azoricum'', the small adder's-tongue fern or lesser adder's-tongue fern, is a small fern of the family Ophioglossaceae. Distribution ''Ophioglossum azoricum'' is an Atlantic–Mediterranean species native to islands in the nort ...

'' **'' Ophioglossum californicum'' **'' Ophioglossum caroticaule'' **'' Ophioglossum convexum'' **'' Ophioglossum coriaceum'' **'' Ophioglossum fernandezianum'' – doubtful species ** ''Ophioglossum'' × ''giovanninii'' **'' Ophioglossum gracile'' – may be included in ''O. gramineum'' **'' Ophioglossum gracillimum'' **''

Ophioglossum gramineum ''Ophioglossum'', the adder's-tongue ferns, is a genus of about 50 species of ferns in the family Ophioglossaceae. The name ''Ophioglossum'' comes from the Greek meaning "snake-tongue".

'' **'' Ophioglossum harrisii'' **'' Ophioglossum jaykrishnae'' – provisionally accepted name **''

Ophioglossum kawamurae ''Ophioglossum'', the adder's-tongue ferns, is a genus of about 50 species of ferns in the family Ophioglossaceae. The name ''Ophioglossum'' comes from the Greek meaning "snake-tongue".

'' **'' Ophioglossum lancifolium'' **'' Ophioglossum latifolium'' **'' Ophioglossum lineare'' – possibly a synonym of ''O. parvifolium'' **'' Ophioglossum louisii'' **''

Ophioglossum lusitanicum ''Ophioglossum lusitanicum'', the least adder's-tongue, is a small fern of the family Ophioglossaceae. It is a pan-tropically species categorised as least concern by the IUCN (2001). Description ''Ophioglossum lusitanicum'' is a small winter ...

'' **'' Ophioglossum lusoafricanum'' **'' Ophioglossum melipillense'' **'' Ophioglossum namegatae'' – probably a synonym of ''O. petiolatum'' **'' Ophioglossum oblongum'' **'' Ophioglossum parvifolium'' **'' Ophioglossum parvum'' **'' Ophioglossum petiolatum'' ** ''Ophioglossum'' × ''pierinii'' **'' Ophioglossum polyphyllum'' ** ''Ophioglossum'' × ''pseudoazoricum'' **''

Ophioglossum pusillum ''Ophioglossum pusillum'' is a species of fern in the family Ophioglossaceae known by the common name northern adder's tongue. It is native to northern North America, where it is widespread in moist areas such as marshes, fens, and meadows. It i ...

'' **''

Ophioglossum reticulatum ''Ophioglossum reticulatum'', the netted adder's-tongue, is a species of fern in the family Ophioglossaceae. It has a pantropical/pansubtropical distribution; Latin America, the Caribbean, Sub-Saharan Africa, Madagascar, Yemen, the Indian Subcont ...

'' **'' Ophioglossum sandieae'' **'' Ophioglossum scariosum'' **'' Ophioglossum thermale'' **'' Ophioglossum thomasii'' **'' Ophioglossum trilokinathii'' **''

Ophioglossum vulgatum ''Ophioglossum vulgatum'', commonly known as adder's-tongue, southern adders-tongue or adders-tongue fern, is a species of fern in the family ''Ophioglossaceae''. The adder’s tongue fern is generally believed to have the largest number of chro ...

'' **'' Ophioglossum yongrenense'' Species that may be placed in this genus include: *''Ophioglossum bergianum'' = '' Rhizoglossum bergianum'' *''Ophioglossum falcatum'' = ''

Ophioderma falcatum ''Ophioderma falcatum'' is known as puapua moa or laukahi in Hawaii. It is a fern in the family Ophioglossaceae, and many people still classify it as an ''Ophioglossum''. Some consider it a subspecies of ''Ophioderma pendulum''. An epiphyte A ...

'' *''Ophioglossum intermedium'' = '' Ophioderma intermedium'' *''Ophioglossum simplex'' = '' Ophioderma simplex''

References

External links

Flora of North America: ''Ophioglossum'' (Adder's-tongue)
{{Taxonbar, from=Q781270 Ophioglossaceae Fern genera Taxa named by Carl Linnaeus