Practical ecological knowledge for the temperate reader.

Ceratophyllum demersum - Common Hornwort

Family: Ceratophyllaceae (Hornwort) [E-flora]

Origin Status: Native [E-flora]

"Ceratophyllum demersum is a PERENNIAL growing to 1 m (3ft 3in) at a fast rate. It is hardy to zone (UK) 8. It is in flower from Jul to September. The flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and are pollinated by Water.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers wet soil and can grow in water." [PFAF]

Edible Uses


"Seed - we have no details on this species but would suggest sowing the seed as soon as it is ripe in early autumn in a greenhouse with the pot immersed in water. It is likely that the seed will quickly lose viability if allowed to dry out so if it is stored it should be kept cool in a container of water and then be sown in late winter. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in a tray of water in the greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Cuttings in the growing season root easily[188]. Plants propagate themselves naturally when scaly young shoots or winter buds separate from the main plant[188]." [PFAF]


"Prefers a sandy medium rich in decaying organic matter in full sun, but it tolerates shade better than most submerged aquatic plants[188]. A good pond oxygenator, it usually grows submerged in the water but is sometimes found floating on the surface[1, 188]. This species belongs to one of only two known dicot genera where pollination taks place under water. The anthers of male flowers break off the plant and float to the surface where they release their pollen grains. These then sink under the water to fertilize the female flowers[274]. This species, however, more commonly reproduces asexually[274]. In some parts of the world bilharzia-carrying snails and malaria-carrying mosquito larvae shelter in the leaves of plants of this genus. The plants can also grow so vigorously as to choke waterways, though they also provide good shelter for young fish[274]. The plant is very brittle[1]." [PFAF]



  1. [Duke] Duke Phytochemical Database, James A. Duke, Accessed Feb , 2014,
  2. [E-flora], Accessed Feb 1, 2015
  3. [PFAF], Accessed Feb 1, 2015; May 5, 2021

Ceratophyllum Sp. - Hornwort

"(Greek: horn leaf, for antler-like appearance) Ceratophyllum grown as ornamental or for oxygen generation in aquaria, garden ponds. Leaves, fruit eaten by migrating waterfowl. Vigorous growth (even of native species) can result in weedy infestations." [????]

Local Species;

  1. Ceratophyllum demersum - Common hornwort [E-flora]
  2. Ceratophyllum echinatum - Spring hornwort [E-flora]

Taxanomic Key to Ceratophyllum

1. Fruits wing-margined, with several lateral spines; leaf divisions fine, threadlike, sometimes with fine teeth C. echinatum
1. Fruits wingless, with only two basal spines; leaf divisions stout, stiff, with distinct teeth C. demersum [E-flora]

Uses of Various Ceratophyllum Sp.

The oldest account known about the use of algae comes from the Chinese King, Shen Nang 2,700 years B.C. Data on the usage of algae in Traditional Indian Medicine (TIM) or Ayurveda is scarce with the exception of Ceratophyllum demersum Linn. (Ceratophyllaceae). The paste of C. demersum is used in bleeding hemorrhoids. It is also used in polydipsia, diarrhea, fever, bleeding diathesis, and biliousness." [????]

Potential Livestock Feed

Ceratophyllum demersum L

"Crude protein concentrations ranged from 5.9% in Panicum hemitomum to 24.6% in Ceratophyllum dernersurn. Many of the species contained more than 10% crude protein. As pointed out earlier by Boyd (1968, 1974), on a dry weight basis many aquatic plants have crude protein concentrations comparable to those of conventional dry forages." [Boyd&McGinty]

Arsenic Hyperaccumulator

Several adventive aquatic weeds in the river (Ceratophyllum demersum, Egeria densa, Lagarosiphon major) act as As(Arsenic) hyperaccumulators [105-108]. [Reeves]


Ceratophyllum echinatum - Spring hornwort

"Spineless hornwort is a perennial floating aquatic species endemic to North America where it is found primarily in the eastern part of the continent and then is disjunct in British Columbia, Washington and Oregon (USDA 2011). In British Columbia, it is found primarily in the southwestern part of the province, in lakes and sloughs in the lowland and montane zones. This species has coarse branching stems and usually no roots. Leaves are forked and arranged in whorls, and are sometimes toothed. Species in this genus are distinctively stiff to touch, and retain their shape when pulled from the water--aiding in identification of the genus." [FNA-E-flora]

"In writing about the rare plants of the Fraser Valley, Lomer (2011) says: "An aquatic plant much like the common C. demersum, but more slender. It tends to grow in clearer, more acidic bog water than the latter species. [In the Fraser Valley], it has been found at Devil's Lake, west of Hope (Ceska 1978, unpublished), and I expect that further collecting will prove that this species is not rare in southwest BC, though there appear to be very few sites in the Fraser Valley."" [FNA-E-flora]

Origin Status: Native [E-flora]

Cultivation & Propagation



  1. [E-flora], Accessed Feb 1, 2015; May 5, 2021

Page last modified on Wednesday, May 5, 2021 9:44 AM