Hydrilla (waterthyme) is a genus of aquatic plant, usually treated as containing just one species, Hydrilla verticillata, though some botanists divide it into several species. It is native to the cool and warm waters of the Old World in Asia, Africa and Australia, with a sparse, scattered distribution; in Australia from Northern Territory, Queensland, and New South Wales.
The Potamogetonaceae, commonly referred to as the pondweed family, is an aquatic family of monocotyledonous flowering plants. The roughly 110 known species are divided over six genera. The largest genus in the family by far is Potamogeton, which contains about 100 species.
Potamogeton is a genus of aquatic, mostly freshwater, plants of the family Potamogetonaceae. Most are known by the common name pondweed, although many unrelated plants may be called pondweed, such as Canadian pondweed. The genus name means "river neighbor", originating from the Greek potamos (river) and geiton (neighbor).
Pondweed refers to many species and genera of aquatic plants and green algae:
Egeria densa, the large-flowered waterweed or Brazilian waterweed, is a species of Egeria native to warm temperate South America in southeastern Brazil, Argentina, Chile and Uruguay. It is considered a problematic invasive species due to its use in home aquariums and subsequent release into non-native ecosystems.
Potamogeton natans, commonly known as broad-leaved pondweed, floating pondweed, or floating-leaf pondweed, is an aquatic species in the genus Potamogeton native to quiet or slow-flowing freshwater habitats throughout the Holarctic Kingdom.
Potamogeton perfoliatus is a perennial aquatic plant in the family Potamogetonaceae occurring in both standing and flowing freshwater habitats. It is widely distributed globally, occurring in all continents except South America and Antarctica.
Potamogeton praelongus, commonly known as whitestem pondweed in North America and long-stalked pondweed in Britain, is a large, perennial aquatic plant in the family Potamogetonaceae. It is widely distributed in lakes and rivers in the northern hemisphere, but is sensitive to poor water quality.
Potamogeton coloratus, the fen pondweed, is an aquatic plant in the genus Potamogeton. It is found in shallow peaty calcareous lakes, ponds and ditches, commonly associated with lowland fens.
Potamogeton lucens, or shining pondweed, is an aquatic perennial plant native to Eurasia and North Africa. It grows in relatively deep, still or slow-flowing, calcareous freshwater habitats.
Potamogeton alpinus is a species of perennial aquatic plant known by the common names alpine pondweed and red pondweed. It is widespread in the northern hemisphere in both rivers and lakes with good water quality.
Potamogeton gramineus is a species of aquatic plant known by the common name various-leaved pondweed, variableleaf pondweed, grass-leaved pondweed or grassy pondweed, native to the northern hemisphere where it grows in shallow, clean water.
Potamogeton nodosus is a species of aquatic plant known by the common names longleaf pondweed and Loddon pondweed. It is native to Eurasia and the Americas, where it is widespread and can be found in water bodies such as ponds, lakes, ditches, and streams. This is a perennial herb producing a thin, branching stem easily exceeding a meter in maximum length. The leaves are linear to widely lance-shaped and up to 15 centimeters long by 4 wide. Both floating leaves and submerged leaves are borne on long petioles, a distinguishing characteristic. The inflorescence is a spike of many small flowers arising from the water on a peduncle.
Potamogeton pusillus is a species of aquatic plant known by the common names small pondweed, lesser pondweed or least pondweed. It occurs in standing and slow-flowing freshwater habitats throughout the Northern Hemisphere.
Potamogeton compressus is a species of aquatic plant known by the common names grass-wrack pondweed, flatstem pondweed and eel-grass pondweed.
Potamogeton obtusifolius, known as blunt-leaved pondweed, is an aquatic plant in the genus Potamogeton. It grows mainly in mesotrophic to eutrophic lakes, ponds and ditches, rarely in brackish water. It occurs primarily in Central Europe, the British Isles, Fennoscandia and eastern North America.
Potamogeton acutifolius is a European species of aquatic plant in the family Potamogetonaceae, known by the common name sharp-leaved pondweed. It is threatened and declining in at least part of its range.
Potamogeton trichoides is a species of aquatic plant known by the common name hairlike pondweed, native to Europe and western Asia where it grows in calcareous, usually nutrient-rich standing or slow-flowing water.
Potamogeton friesii, known as flat-stalked pondweed, or Fries' pondweed, is an aquatic plant in the genus Potamogeton. It grows mainly in mesotrophic to eutrophic rivers, lakes, ponds and ditches, rarely in brackish water. It occurs in North America, Europe, western Asia and a few scattered locations elsewhere in Asia.
Oenanthe fluviatilis, the river water-dropwort, is a flowering plant in the carrot family, Apiaceae, which is endemic to north-west Europe. It grows only in clear, unpolluted rivers and is declining throughout its range.
