Oxygenators

Callitriche (Callitrchaceae)
Water starwort.

The 25 species in this genus are distributed throughout the world except South Africa. They are small slender plants, and they generally grow in a tight mass  in a wide range of habitats, but mainly in temperate locations. Most species are recongnizable by their terminal rosettes of leaves, which, when floating on the water, give rise to the common name.

Ceratophyllum (Ceratophyllaceae)

The genus contains about 30 hardy species of submerged rootless aquatics found around the world. They grow only in submerged conditions and are unable to tolerate even the shortest time out of the water. They flourish in cold water and shade, conditions that could inhibit other species.

Egeria (Hydrocharitaceae)

The two species of evergreen or semi-evergreen submerged plants in this genus were originally native to the warn and temperate zones of South America, but they have become established elsewhere, sometimes becoming so invasive that they are regarded as pests.

Hottonia (Primulaceae)

The genus containes two species of submerged plants which have primula-like flowers, held above the water. The two species are mainly found in bright, clear pools or slow moving ditches in temperate areas of the northern hemisphere.

Lagarosiphon (Hydrocharitaceae)
Curly water thyme

There are nine species of tender, submerged plants in this genus. They are native to central Africa and Madagascar, but they have also established themselves in Europe and New Zealand. Similar to Egeria, curly water thyme is an excellent oxygenator for fish bowls, pools and aquaria.

Myriophyllum (Haloragaceae)
Milfoil

The 40 species of submerged aquatics in this genus are mainly from the souther hemisphere. The submerged stems are often long, bearing finely divided, almost feathery leaves, which are extremely attractive. The milfoils show a great diversity of habit, and many love to creep out of the water and sramble onto the surrounds of the pool

Potamogeton (Potamogetonaceae)

There are 8-100 species of submerged aquatic plants in this genus, and they are found in temperate regions throughout the world. They are vigorous rhizomatous perennials, and only a few are suitable as oxygenators in decorative ponds as they can quickly choke other growth.

Ranunculus (Ranunculaceae)

This large genus containes about 400 species of temperate and tropical moisture-loving and aqautic species, which have a big impact in a garden.