Ceratophyllum

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Ordo: Ceratophyllales

Familia: Ceratophyllaceae
Genus: Ceratophyllum
Species: C. australe – C. demersum – C. echinatum – C. muricatum – C. submersum – C. tanaiticum
Source(s) of checklist:
Name

Ceratophyllum L.

Type species: Ceratophyllum demersum L.

Synonyms

Heterotypic
Hydroceratophyllon Ség., Pl. Veron. 3: 62 (1754).
Dichotophyllum Moench, Methodus: 345 (1794).
Revatophyllum Röhl., Deutschl. Fl., ed. 2, 2: 514 (1812).

References
Primary references

Linnaeus, C. 1753. Species Plantarum. Tomus II: 992. Reference page.

Links

Govaerts, R. et al. 2019. Ceratophyllum in World Checklist of Selected Plant Families. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the internet. Accessed: 2019 October 07. Reference page.
International Plant Names Index. 2019. Ceratophyllum. Published online. Accessed: October 07 2019.
Tropicos.org 2019. Ceratophyllum. Missouri Botanical Garden. Published on the internet. Accessed: 2019 October 07.

Vernacular names
العربية: شمبلان
azərbaycanca: Buynuzyarpaq
башҡортса: Мөгөҙьяпраҡ
беларуская: Рагаліснік
čeština: růžkatec
dansk: Hornblad
Deutsch: Hornblatt
English: Hornwort
eesti: Kardhein
فارسی: علف شاخی
suomi: Karvalehdet
français: Cornifle, cératophylle
hornjoserbsce: Rohačk
հայերեն: Եղջերատերև
ქართული: რქაფოთოლა
қазақша: Мүйізжапырақ
한국어: 붕어마름속
lietuvių: Nertis
latviešu: Raglapes
Nederlands: Hoornblad
norsk: Hornblader
Ирон: Сыкъасыф
polski: Rogatek
русский: Роголистник
саха тыла: Бэчимэ от
slovenčina: rožkatec
svenska: Särvsläktet
中文: 金鱼藻属

Ceratophyllum is a cosmopolitan genus of flowering plants including four accepted living species in 2016,[2] commonly found in ponds, marshes, and quiet streams in tropical and in temperate regions. It is the only extant genus in the family Ceratophyllaceae,[1] itself the only extant family in the order Ceratophyllales.[3] They are usually called coontails or hornworts, although hornwort is also used for unrelated plants of the division Anthocerotophyta.

Ceratophyllum grows completely submerged, usually, though not always, floating on the surface, and does not tolerate drought. The plant stems can reach 1–3 m in length. At intervals along nodes of the stem they produce rings of bright green leaves, which are narrow and often much-branched. The forked leaves are brittle and stiff to the touch in some species, softer in others. The plants have no roots at all, but sometimes they develop modified leaves with a rootlike appearance, which anchor the plant to the bottom. The flowers are small and inconspicuous, with the male and female flowers on the same plant. In ponds it forms thick buds (turions) in the autumn that sink to the bottom which give the impression that it has been killed by the frost but come spring these will grow back into the long stems slowly filling up the pond.[4][5][6][7]

Taxonomy

Ceratophyllum is considered distinctive enough to warrant its own family, Ceratophyllaceae. It was considered a relative of Nymphaeaceae and included in Nymphaeales in the Cronquist system, but recent research has shown that it is not closely related to Nymphaeaceae or any other extant plant family. Some early molecular phylogenies suggested it was the sister group to all other angiosperms, but more recent research suggests that it is the sister group to the eudicots. The APG III system placed the family in its own order, the Ceratophyllales.[1][8][9] The APG IV system accepts the phylogeny shown below:[3]

angiosperms

Amborellales       Nymphaeales       Austrobaileyales       magnoliids     Chloranthales       monocots       Ceratophyllales     eudicots

 
Species

The subgeneric division of the genus Ceratophyllum into its appropriately recognized species, subspecies, and varieties is not settled. More than 30 species have been described and published. A narrow interpretation of this work rejects over 24 of these taxa as variants, accepting only 6 species. This narrow interpretation lumps to the point of failing to give these potential species the taxonomic importance of even being named on a subspecific or varietal level. The genus as narrowly defined in this manner contains the following six species:[1][4][5][10][11][12][13]

Ceratophyllum australe Griseb.
Ceratophyllum demersum L. (rigid/common hornwort) – cosmopolitan
Ceratophyllum echinatum A.Gray (spiny hornwort) – North America
Ceratophyllum muricatum Cham. (prickly hornwort) – Near-cosmopolitan
Ceratophyllum platyacanthum Cham. – Europe and Asia
Ceratophyllum submersum L. (soft/tropical hornwort) – Europe, Middle-East, Central Asia, northern and central Africa, Florida, and Dominican Republic
Ceratophyllum tanaiticum Sapjegin

References

Kew World Checklist of Selected Plant Families
Christenhusz, M. J. M.; Byng, J. W. (2016). "The number of known plants species in the world and its annual increase". Phytotaxa. 261 (3): 201–217. doi:10.11646/phytotaxa.261.3.1.
Angiosperm Phylogeny Group (2016). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV". Botanical Journal of the Linnean Society. 181 (1): 1–20. doi:10.1111/boj.12385.
Flora of China: Ceratophyllum
Flora of North America: Ceratophyllum
Blamey, M. & Grey-Wilson, C. (1989). Flora of Britain and Northern Europe. ISBN 0-340-40170-2
Huxley, A., ed. (1992). New RHS Dictionary of Gardening. Macmillan ISBN 0-333-47494-5.
Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III". Botanical Journal of the Linnean Society. 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x.
Angiosperm Phylogeny Web: Ceratophyllales
Germplasm Resources Information Network: Ceratophyllum
Australian Plant Name Index: Ceratophyllum
Flora Europaea: Ceratophyllum
http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:330840-2#children