| Potamogeton coloratus | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Alismatales |
| Family: | Potamogetonaceae |
| Genus: | Potamogeton |
| Species: | P. coloratus |
| Binomial name | |
| Potamogeton coloratus Hornem. | |
| Synonyms [1] | |
| |
Potamogeton coloratus, the fen pondweed, [2] is an aquatic plant in the genus Potamogeton . It is found in shallow peaty calcareous lakes, ponds and ditches, commonly associated with lowland fens.
Fen pondweed grows from perennial, creeping rhizomes. The leaves are broad, thin and translucent with noticeable reticulate veining. [3] Both floating and submerged leaves are produced but the difference between these is often rather indistinct, rather than the marked dimorphism seen in other pondweeds. Often, the leaves of fen pondweed are simply longer and narrower lower down the stem and shorter and rounder towards its apex; the leaves towards the apex of the stem may be floating but often grow just below the surface, giving the plant a distinctive 'drowned' appearance, [3] as though water levels have recently risen. Submerged leaves are 70–175 mm long and 10–30 mm wide. [3] All leaves have the stalk shorter than the blade, and the submerged leaves are almost sessile. [4] The leaves are typically reddish to brownish in colour.
Flowers are produced in June to July. Like all pondweeds, they are small and greenish, in spikes up to 45 mm long. The fruits of this species are smaller (1.5-1.9 mm long x 1.0-1.3 mm wide) than Broad-leaved pondweed Potamogeton natans and Bog Pondweed Potamogeton polygonifolius . [3] [4] Turions are not produced. [3]
Fen pondweed could be confused with other pondweeds, especially bog pondweed P. polygonifolius, to which it is closely related. [5] However, bog pondweed produces completely opaque floating leaves that are very distinct from the submerged leaves; the submerged leaves are longer and die back relatively early in the season. Bog pondweed also lacks the distinctive net-veined appearance. Potamogeton lucens has leaves with a similar net-veined appearance, but is more uniform in its growth habit, has denticulate (finely toothed) leaf margins and stipules with two conspicuous keels. [3]
Potamogeton coloratus is diploid, with 2n=28. [6]
Hybrids have been described with P. berchtoldii (P. × lanceolatusSm.) and P. gramineus (P. × billupsiiFryer), but both are rare. [3] [7]
Fen pondweed was first named by the Danish botanist Jens Wilken Hornemann (1770–1841). [1] The specific epithet means 'coloured', 'dark', or 'tanned'. As this is a fairly distinctive and not very variable species, there are relatively few synonyms.[ citation needed ]
Potamogeton coloratus is restricted to Europe (Britain, Ireland, Netherlands, Belgium, Denmark, Sweden (Gotland only), France including Corsica, Italy including Sardinia and Sicily, Switzerland, Austria, Hungary, Spain (Balearic Islands) and Portugal), [8] Turkey [9] and extreme North Africa (Morocco, Algeria). [8]
Fen pondweed has rather specialised habitat preferences, occurring predominantly on deep peat with nutrient-poor calcareous water and a strong groundwater influence, such as is commonly found in alkaline fenlands. Within this habitat it occurs predominantly in ponds, ditches and drains, flushes and seeps, and the margins of shallow lakes, [7] in water up to about 1 m deep, often in the company of stoneworts [3] and bladderworts. In central Europe, it forms a distinct community with Chara hispida and the aquatic form of Juncus subnodulosus in oligotrophic, calcium-rich, spring-fed streams [10] and oxbow lakes. [11] It will also grow on marl, sand and clay. [12] In Britain and central Europe [10] it has been lost from many sites due to eutrophication or drainage, and most remaining populations are in nature reserves. [12] However, where it is found it can be abundant, such as on the Anglesey Fens in North Wales. Fen pondweed remains widespread in Ireland.
A study of the genetic diversity of fen pondweed in the managed ditch systems of the Gordano Valley in southwest England showed that genetic diversity increased with distance from the head of the valley. This was interpreted as reflecting population bottlenecks caused by ditch cleaning, and the tendency for dispersal to occur downstream. [13]
Pond snails such as Lymnaea stagnalis may consume fen pondweed, but it is rather unpalatable compared to other aquatic plants. [14]
Globally [7] and in Britain, [15] fen pondweed is considered Least Concern. However, it is a protected feature of several fenland nature reserves in Britain, both in its own right [16] and as a characteristic species of fenland habitat and the Habitats Directive habitats "Hard oligotrophic lakes with Chara" and "Natural eutrophic lakes with Magnopotamion". [17] Effective conservation of this species depends upon protection of its lowland calcareous fenland habitat.
Fen pondweed was formerly extinct in the Czech Republic, but has recently been reestablished from the seed bank following desilting of some of its former habitat. [18] It is considered Endangered in Germany [19] and Switzerland, [20] Vulnerable in the Netherlands [21] and is Near Threatened in Sweden. [7] It is protected in several French administrative regions. [7]
Fen pondweed is not in cultivation, and does not seem particularly easy to grow, reflecting its specialist habitat requirements. It would probably need to be grown in a rather deep, peaty but alkaline substrate.[ citation needed ]
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).
Potamogeton crispus, the crisp-leaved pondweed, curly pondweed, curly-leaf pondweed or curled pondweed, is a species of aquatic plant (hydrophyte) native to Eurasia but an introduced species and often a noxious weed in North America.
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 polygonifolius or bog pondweed, is an aquatic plant. It is found in shallow, nutrient-poor, usually acid standing or running water, bogs, fens and occasionally ditches.
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 diversifolius is a species of aquatic plant known by the common names waterthread pondweed and diverse-leaved pondweed. It is native to most of the United States, as well as sections of southwestern Canada, and northern Mexico, where it grows in water bodies such as ponds, lakes, ditches, and slow-moving streams. This is a perennial herb producing a very narrow, compressed stem branching to a maximum length around 35 centimeters. It has thin, pointed linear leaves a few centimeters long spirally arranged about the thin stem. The inflorescence is a small spike of flowers emerging from the water surface. Inflorescences also grow on submersed sections of the stem; these are smaller and spherical. It can be difficult to distinguish from similar species of pondweed.
Potamogeton epihydrus is a perennial aquatic plant known by the common names ribbonleaf pondweed and Nuttall's pondweed, and American pondweed in the United Kingdom. It is native to much of North America, where it grows in water bodies such as ponds, lakes, ditches, and slow-moving streams.
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 berchtoldii, common name small pondweed is an aquatic plant.
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 × angustifolius is a hybrid pondweed between Potamogeton gramineus and Potamogeton lucens, known as long-leaved pondweed. It is widespread in rivers and lakes except where the water is very soft.
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.
