P. gramineus occurs throughout most of Europe, from Spain north to Ireland and Iceland, east throughout European Russia, to Turkey and the northern Mediterranean. Outside Europe, it occurs throughout northern Asia east to the Korean Peninsula and Japan and throughout most of North America (The Board of Trustees of the Royal Botanic Gardens, Kew 2010).
Regularity: Regularly occurring
Regularity: Regularly occurring
Global Range: Circumboreal. Que., N.S., Nfld., Lab. AK, AZ, CA, CO, CT, IA, ID, IL, IN, KS, MA, ME, MI, MN, MO, MT, ND, NE, NH, NJ, NM, NV, NY, OH. OR, PA, RI, SD, VT, WA, WI, WV, WY.
Stem terete or slightly flattened, not black spotted. Many submersed leaves more than 4 mm wide, 3-8 cm long, with 3-9 veins, sessile, not cordate or auriculate at the base. Stipular sheath 1-3 cm long. Beak of the achene less than 1.5 mm long and lacking a basal appendage. Plants not red tinged.
Habitat and Ecology
P. gramineus will occur in most oligotrophic to mesotrophic water body types, from large lakes through ponds to temporary pools in fens and marshes as well as streams and even fairly large, fast-flowing rivers.
Extremely variable in size and shape fluctuation may be due to differences in depth and velocity of the waters in which it grows.
Life History and Behavior
N=26, frequently hybridizes.
Molecular Biology and Genetics
Barcode data: Potamogeton gramineus
Statistics of barcoding coverage: Potamogeton gramineus
Public Records: 8
Specimens with Barcodes: 12
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
Rounded National Status Rank: NNR - Unranked
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
There are no known past, ongoing, or future threats to the survival of this species.
It is classed as Critically Endangered in the Czech Republic (Procházka 2001). There are no conservation measures in place or needed.
Potamogeton gramineus is a species of aquatic plant known by the common name various-leaved pondweed,variableleaf pondweed, or grassy pondweed. This is a perennial herb growing from a creeping rhizome that anchors in wet substrate. It produces thin, cylindrical, heavily branching stems usually less than a metre in length. The submerged leaves are sessile, relatively narrow, typically 40–90 mm long and 5–12 mm wide along the main stem but smaller on the side branches. They are translucent and pale green with a white midrib, and finely toothed. Floating leaves are more oval in shape, 20–70 mm long by 7–34 mm wide, and borne on long petioles. The inflorescence is a short spike of many flowers arising from the water on a stout peduncle.
This species readily hybridizes with many other species of Potamogeton. Hybrids have been recorded with P. perfoliatus, P. lucens, P. natans, P. coloratus, P. alpinus and P. polygonifolius. In Britain, the hybrids with P. perfoliatus (P. x nitens) and P. lucens (P. x angustifolius) are quite common. Recent molecular analysis has shown that Swedish collections of the putative hybrid P. gramineus x P. polygonifolius are in fact P. gramineus x P. nodosus
As well as hybridising frequently, various-leaved pondweed is an extremely variable plant and care should be taken with its identification.
Distribution, Ecology and Conservation
Potamogeton gramineus is native to much of the Northern Hemisphere, where it grows in water bodies such as ponds, lakes, bogs, and streams. It is usually restricted to shallower water <1 m deep, though it has been recorded growing at more than 5 m depth in Llynnau Cregennen, Wales. It is intolerant of nutrient pollution and is not usually found in base-poor water of alkalinity less than about 200 ueq l−1.
In Britain, it has shown the same pattern of decline as other broad-leaved pondweeds such as P. praelongus and P. alpinus, with most losses occurring in southern Britain. This likely reelects increasing eutrophication, canalization of rivers leading to loss of backwater habitats and other floodplain standing waters, and degradation or loss of pond and lake habitats. P. gramineus may also grow in open reedbeds, and the loss of traditional reed cutting practices may have caused the loss of populations from this habitat. It is also scarce and of conservation importance in Spain. Local extinction has also been recorded in Lower Saxony between 1948 and 1986
Indices of environmental tolerance using trophic ranking schemes in Europe tend to show P. gramineus to be one of the more nutrient-sensitive aquatic plants, Studies in Holland show P. gramineus to be associated with Littorelletea lakes, and to be one of a suite of species sensitive to acidification.
Various-leaved pondweed is one of the so-called Magnopotamion group of pondweeds. These are a characteristic floristic component of the protected Habitats Directive habitat Type 'Natural eutrophic lakes with Magnopotamion'. However, in Britain P. gramineus also occurs in more oligotrophic waters.
P. gramineus is not in general cultivation, though it is an attractive plant and grows well in a garden pond. Its slower growth than most submerged species, attractive leaves and habit of producing a limited number of floating leaves make it very ornamental and suitable for garden ponds, and its smaller size than many other pondweeds is also a benefit. In common with other pondweeds of this group it roots poorly from stem cuttings and is best propagated by division of the rhizomes.
- Preston C.D. (1995). Pondweeds of Great Britain and Ireland. BSBI Handbook No. 8. Botanical Society of the British Isles, London.
- Kaplan, Z. & Fehrer, J. (2011) Erroneous identities of Potamogeton hybrids corrected by molecular analysis of plants from type clones. Taxon, 60, 758-766.
- Goldsmith B, Salgado, J, Shilland, J, Yang, H & Turner, SD. 2014. Biodiversity Action Plan Lakes Survey 2012-14. NRW Evidence Report No: 27, 168pp, Natural Resources Wales, Bangor
- Preston C.D., Pearman D.A., Dines T.D. (2002) New Atlas of the British and Irish Flora: An Atlas of the Vascular Plants of Britain, Ireland, the Isle of Man and the Channel Islands. Oxford University Press, Oxford.
- Fernández Aláez M., Fernández Aláez C., Rodríguez S. & Bécares C. (1992) Evaluation of the state of conservation of shallow lakes in the province of Leon (Northwest Spain) using botanical criteria. Limnetica, 17, 107-117
- Wiegleb G., Brux H. & Herr W. 1991. Human impact on the ecological performance of Potamogeton species in northwestern Germany. Vegetatio , 97, 161-172.
- UK Water Framework Directive Techical Advisory Group (UKTAG). 2014. UKTAG Lake Assessment Method: Macrophytes and Phytobenthos: Macrophytes (Lake LEAFPACS2). ISBN 978-1-906934-45-3. Available online at Lakes Leafpacs
- UK Water Framework Directive Techical Advisory Group (UKTAG). 2014. UKTAG River Assessment Method: Macrophytes and Phytobenthos: Macrophytes (River LEAFPACS2). ISBN 978-1-906934-44-6. Available online at River Leafpacs
- UK Water Framework Directive Techical Advisory Group (UKTAG). 2008. UKTAG River Assessment Method: Macrophytes and Phytobenthos: Macrophytes (Free Index). ISBN 978-1-906934-02-6. Available online at Lake Macrophytes Free Index
- Roelofs J.G.M. 1983. Impact of acidification and eutrophication on macrophyte communities in soft waters in the Netherlands. I. Field Observations. Aquatic Botany, 17, 139-155
- "Joint Nature Conservation Committee: 3150 Natural Eutrophic Lakes". Retrieved 2014-10-19.
Three varieties were recognized (E. C. Ogden 19435) and treated (M. L. Fernald 1950). These varieties, Potamogeton gramineus var. gramineus, deletion}P. gramineus var. myriophyllus, and P. gramineus var. maximus, were said to be separated by the shape and size of the submersed leaves. We have studied many populations of this species in the field and have observed on several occasions that a single population has leaf morphology variable enough to include all three varieties. We have, , therefore , chosen not to recognize any infraspecific categories for this species.