Hornwort

Ceratophyllum demersum

Hornwort (Ceratophyllum demersum) is a rootless, free-floating submerged aquatic plant found in freshwater habitats worldwide. It grows in dense, bushy masses with branching stems reaching 1-3 meters in length. The leaves are dark green, stiff, and forked into narrow, toothed segments arranged in whorls around the stem, giving the plant a foxtail-like appearance. Unlike most aquatic plants, hornwort lacks true roots and either floats freely or anchors itself loosely to the substrate by modified leaves. It reproduces primarily through fragmentation and can grow rapidly, forming extensive underwater meadows. These stands provide critical habitat for aquatic organisms including juvenile fish, invertebrates, and amphibian larvae. The plant is an efficient oxygenator and water purifier, absorbing excess nutrients and helping to prevent algal blooms. Freshwater divers encounter hornwort in lakes, ponds, slow rivers, and springs, where it creates beautiful underwater landscapes reminiscent of terrestrial forests in miniature. It tolerates a wide range of water conditions and can be found from tropical to temperate latitudes.