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Common Name: Hornwort
Ceratophyllum demersum is a
Most of Europe, including Britain, but absent from the Arctic.
Ponds and ditches[
Prefers a sandy medium rich in decaying organic matter in full sun, but it tolerates shade better than most submerged aquatic plants[
A good pond oxygenator, it usually grows submerged in the water but is sometimes found floating on the surface[
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[
]. This species, however, more commonly reproduces asexually[
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[
The plant is very brittle[
]. No further details are given.
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[
Plants propagate themselves naturally when scaly young shoots or winter buds separate from the main plant[