| Ceratophyllaceae | |
|---|---|
 | |
| Ceratophyllum submersum | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Order: | Ceratophyllales Link[1] |
| Family: | Ceratophyllaceae Gray |
| Genera | |
Ceratophyllaceae is acosmopolitanfamily offlowering plants including one living genus[3] commonly found in ponds, marshes, and quiet streams in tropical and in temperate regions. It is the onlyextant family in the orderCeratophyllales.[4] Species are commonly calledcoontails or hornworts, although hornwort is also used for unrelated plants of the divisionAnthocerotophyta.
LivingCeratophyllum grows completely submerged, usually, though not always, floating on the surface, and does not tolerate drought.
Ceratophyllaceae was considered a relative ofNymphaeaceae and included inNymphaeales in theCronquist system, but research has shown that it is not closely related to Nymphaeaceae or any other extant plant family. Some early molecular phylogenies suggested it was thesister group to all other angiosperms, but more recent research suggests that it is the sister group to theeudicots. TheAPG III system placed the family in its own order, the Ceratophyllales.[1][2][5] TheAPG IV system accepts the phylogeny shown below:[4]
The extinct family Montsechiaceae containing the genusMontsechia has also been placed in the order Ceratophyllales.[6]
The family contains one living genus, and several extinct genera described from the fossil record, including one of the earliest fruit bearing (in the form of an achene) plants, the Dakota formation freshwater genusDonlesia from Early Cretaceous.[7]
Orders offlowering plants (APG IV) | ||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|  | |||||||||||||||||||||||||||||||||||||||||||||||||
