Potamogeton pusillus

L.

Slender Pondweed

G5Secure Found in 1 roadless area NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.128182
Element CodePMPOT030X0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassMonocotyledoneae
OrderNajadales
FamilyPotamogetonaceae
GenusPotamogeton
Other Common Names
Potamot nain (FR) small pondweed (EN) Small Pondweed (EN)
Concept Reference
Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.
Taxonomic Comments
This record is for a broad treatment of Potamogeton pusillus, including as subspecies, ssp. gemmiparus and ssp. tenuissimus, as recognized by Haynes and Hellquist in FNA (2000, vol. 22) and Kartesz (1999). Les et al. (2009) exclude ssp. tenuissimus, recognizing it as a species, P. brechtoldii, with ssp. gemmiparus as a subspecies of it along with ssp. clystocarpus, which was recognized as a distinct species in FNA (2000) and Kartesz (1999).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2024-10-01
Change Date1988-02-11
Edition Date2024-10-01
Edition AuthorsN. Ventrella (2024)
Threat ImpactUnknown
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Potamogeton pusillus is an annual or perennial aquatic forb occurring in fresh to brackish, still to flowing, and tidal and non-tidal waters of North, Central, and South America, Greenland, Africa, Europe, and Asia. There are over 2,000 occurrences of this taxon, which are potentially threatened by eutrophication, development, water diversion, alteration of hydrology, erosion, recreational activities, invasive species, climate change, and other threats in some places, though there is insufficient data, including anecdotal accounts, to understand scope and severity of threats for this species. Little is known about threats or trends, but with a large range extent, high number of occurrences, abundant habitat, broad habitat preferences, and no obvious intrinsic vulnerabilities, Potamogeton pusillus is considered secure.
Range Extent Comments
Potamogeton pusillus occurs nearly worldwide in North, Central, and South America, Greenland, Africa, Europe, and Asia (POWO 2024). In North America, it occurs all throughout the United States and Canada (FNA 2000). Range extent was estimated to be over 214 million square kilometers using herbarium specimens and photo-based observations documented between 1993 and 2024 (GBIF 2024, iNaturalist 2024, SEINet 2024).
Occurrences Comments
By applying a 1 km separation distance to herbarium records and photo-based observations documented between 1993 and 2024, there are estimated to be over 2,000 occurrences rangewide (GBIF 2024, iNaturalist 2024, SEINet 2024). However, due to different treatments of this entity (especially as North American and European concepts may differ), and difficulties in identifying members of this group, herbarium records and photo-based observations may underrepresent or overrepresent true abundance.
Threat Impact Comments
Potamogeton pusillus is fairly intolerant of eutrophication, and populations have disappeared from a number of eutrophied sites, only to reappear several decades later once water quality had been restored (Les 2020). Additional threats are not widely documented but likely include development, water diversion, alteration of hydrology, erosion, recreational activities, invasive species, climate change, and other threats in some places, though there is insufficient data, including anecdotal accounts, to understand scope and severity of threats for this species.
Ecology & Habitat

Habitat

Potamogeton pusillus occurs "in fresh to brackish (salinity levels to 3.5–5.3‰), still to flowing, tidal or non-tidal backwaters (shallow), bayous, bays (small), borrow pits, canals, channels (boat, river), ditches (irrigation, roadside), flowages, gravel bars, lakes (boggy, eutrophic, glacial, prairie), marshes (freshwater, oligohaline), ponds (beaver, glacial, mesotrophic, seepage), pools (swampy, tidal), reservoirs (stockpond), river bottoms, rivers (mouths, shores), sloughs, streams (alkaline), and vernal pools" (Les 2020). This species occurs in full sun in a broad range of ecological conditions, but it is typically found in more alkaline waters.

Reproduction

Dispersal occurs through water, waterfowl, and herbivorous fish (Les 2020).

Palustrine Habitats
HERBACEOUS WETLANDFORESTED WETLAND
Other Nations (2)
CanadaN5
ProvinceRankNative
British ColumbiaS5Yes
OntarioSNRYes
Northwest TerritoriesS4Yes
AlbertaSUYes
Yukon TerritoryS5Yes
New BrunswickS5Yes
Island of NewfoundlandS3Yes
NunavutSUYes
ManitobaS4Yes
Prince Edward IslandS4Yes
LabradorS2Yes
SaskatchewanS4Yes
Nova ScotiaS5Yes
QuebecS4Yes
United StatesN5
ProvinceRankNative
OhioSNRYes
OregonSNRYes
NevadaS2Yes
ConnecticutS4Yes
FloridaSNRYes
New MexicoSNRYes
WashingtonSNRYes
MontanaSNRYes
IdahoSNRYes
MarylandS4Yes
WyomingS3Yes
MassachusettsSNRYes
North CarolinaS4Yes
TennesseeSNRYes
VirginiaS4Yes
ArizonaSNRYes
GeorgiaS3Yes
South CarolinaSNRYes
AlaskaSNRYes
OklahomaSNRYes
New JerseySNRYes
MichiganSNRYes
KentuckySNRYes
West VirginiaS3Yes
Rhode IslandSNRYes
IndianaS2Yes
MinnesotaSNRYes
PennsylvaniaSNRYes
IllinoisS3Yes
MaineSNRYes
UtahSNRYes
DelawareS1Yes
VermontS5Yes
NebraskaSNRYes
New YorkSNRYes
LouisianaSNRYes
ArkansasSNRYes
New HampshireSNRYes
IowaS3Yes
MississippiSNRYes
TexasSNRYes
South DakotaSNRYes
CaliforniaSNRYes
North DakotaSNRYes
ColoradoS3Yes
KansasSNRYes
District of ColumbiaSHYes
MissouriSNRYes
WisconsinSNRYes
AlabamaSNRYes
Threat Assessments
ThreatScopeSeverityTiming
9 - PollutionUnknownUnknownUnknown
9.3 - Agricultural & forestry effluentsUnknownUnknownUnknown
9.3.1 - Nutrient loadsUnknownUnknownUnknown

Plant Characteristics
DurationANNUAL, PERENNIAL
Economic Value (Genus)No
Roadless Areas (1)
Montana (1)
AreaForestAcres
Saddle Mountain #168Kootenai National Forest14,675
References (9)
  1. Flora of North America Editorial Committee (FNA). 2000. Flora of North America north of Mexico. Vol. 22. Magnoliophyta: Alismatidae, Arecidae, Commelinidae (in part), and Zingiberidae. Oxford Univ. Press, New York. xxiii + 352 pp.
  2. Global Biodiversity Information Facility (GBIF). 2024. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2024).
  3. iNaturalist. 2024. Online. Available: https://www.inaturalist.org (accessed 2024).
  4. Kaplan, Z. and J.L. Reveal. 2013. Taxonomic identity and typification of selected names of North American Potamogetonaceae. Brittonia 65: 452-468.
  5. Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.
  6. Les, D. 2020. Aquatic Monocotyledons of North America: Ecology, Life History, and Systematics. CRC Press, Boca Raton, FL. 568 pp.
  7. Les, D.H., N.M. Murray, and N.P. Tippery. 2009. Systematics of two imperiled pondweeds (<i>Potamogeton vaseyi, P. gemmiparus</i>) and taxonomic ramifications for subsection Pusilli (Potamogetonaceae). Systematic Botany 34(4): 643-651.
  8. Plants of the World Online (POWO). 2024. Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Online. Available: https://powo.science.kew.org/ (accessed 2024).
  9. Southwest Environmental Information Network (SEINet). 2024. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2024).