Ceratophyllum

Ceratophyllum
Ceratophyllum submersum
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Order:	Ceratophyllales
Family:	Ceratophyllaceae
Genus:	Ceratophyllum L.
Species
See text
Synonyms[1]
Hydroceratophyllon Ség. Dichotophyllum Moench Revatophyllum Röhl. Fassettia Mavrodiev

Ceratophyllum is a

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. Roots are completely absent and are missing even in the embryonic stage,^[5] but sometimes they develop modified leaves with a rootlike appearance, which anchor the plant to the bottom. Also stomata are missing.^[6] 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.^{[7][8][9][10]}

Taxonomy

Ceratophyllum is considered distinctive enough to warrant its own family, Ceratophyllaceae. It was considered a relative of

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:[3]^{[7][8][14][15][1]}

• 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

External links

Wikimedia Commons has media related to Ceratophyllum.

Wikispecies has information related to Ceratophyllum.

• Ceratophyllaceae of Mongolia in FloraGREIF Archived 2012-02-26 at the Wayback Machine