Callitriche palustris

L.

Vernal Water-starwort

G5Secure Found in 3 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.151877
Element CodePDCLL010F0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderPlantaginales
FamilyPlantaginaceae
GenusCallitriche
Other Common Names
Callitriche des marais (FR) vernal water-starwort (EN)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-07-14
Change Date1994-01-07
Edition Date2025-07-14
Edition AuthorsAnnable, C. (1994), rev. N. Ventrella (2025)
Threat ImpactUnknown
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Callitriche palustris is an aquatic perennial forb occurring in rivers, streams, swamps, bogs, lakes, ponds, and springs worldwide, in North America, Greenland, Eurasia, and as an introduced species in Australia. In North America, it occurs throughout all of Canada and Alaska throughout the western United States, south to Mexico, east to Texas and Missouri, Ohio, and Virginia, and north through Maine in the United States. There are several thousand estimated occurrences of this species rangewide, which are potentially threatened by development, recreation, changes to water quality and temperature, invasive species, and alterations to hydrology. Little is known about threats and trends, but with a large range extent, abundant habitat, and broad habitat preferences, Callitriche palustris is considered secure.
Range Extent Comments
Callitriche palustris is widely distributed throughout the northern hemisphere, occurring in North America, Greenland, Eurasia, and as an introduced species in Australia (FNA 2019, POWO 2025). In North America, it occurs throughout all of Canada and Alaska throughout the western United States, south to Mexico, east to Texas and Missouri, Ohio, and Virginia, and north through Maine in the United States (FNA 2019, Weakley and the Southeastern Flora Team 2025). Range extent was estimated to be over 95 million square kilometers using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 1994 and 2025 (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1994 and 2025, it is estimated that there are several thousand occurrences rangewide (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).
Threat Impact Comments
Threats to Callitriche palustris are not well documented but potentially include development, recreation, changes to water quality and temperature, invasive species, and alterations to hydrology. However, they are considered negligible given the broad range and large number of occurrences of the species and its somewhat flexible and abundant habitat.
Ecology & Habitat

Habitat

Callitriche palustris occurs in "fast-flowing rivers and streams, backwaters, ditches, swamps, Sphagnum bogs, lakes, ponds, springs, [and] seepages" from 0-3600 m in elevation (FNA 2019).
Palustrine Habitats
Bog/fen
Other Nations (2)
CanadaN5
ProvinceRankNative
Island of NewfoundlandS4Yes
SaskatchewanS4Yes
New BrunswickS5Yes
QuebecS5Yes
Nova ScotiaS5Yes
Yukon TerritoryS4Yes
LabradorS4Yes
NunavutS3Yes
ManitobaS4Yes
Prince Edward IslandS4Yes
AlbertaS5Yes
OntarioS5Yes
British ColumbiaS5Yes
Northwest TerritoriesS4Yes
United StatesN5
ProvinceRankNative
IdahoSNRYes
Rhode IslandSNRYes
AlaskaSNRYes
New JerseyS2Yes
DelawareSNRYes
MissouriSUYes
South DakotaSNRYes
North DakotaSNRYes
UtahSNRYes
New HampshireSNRYes
TexasSNRYes
OregonSNRYes
VermontS5Yes
ColoradoS4Yes
NevadaS3Yes
PennsylvaniaSNRYes
WashingtonSNRYes
New MexicoSNRYes
IowaSNRYes
WisconsinSNRYes
VirginiaS3Yes
ArizonaS3Yes
New YorkS5Yes
IllinoisSNRYes
WyomingS4Yes
MarylandSNRYes
MontanaSNRYes
MaineSNRYes
ConnecticutSNRYes
MinnesotaSNRYes
MichiganSNRYes
CaliforniaSNRYes
NebraskaS2Yes
OhioS1Yes
MassachusettsSNRYes
West VirginiaS4Yes
Threat Assessments
ThreatScopeSeverityTiming
Unknown/undetermined

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (3)
Alaska (1)
AreaForestAcres
Port AlexanderTongass National Forest120,681
Michigan (1)
AreaForestAcres
Norwich Plains Revised Roadless AreaOttawa National Forest4,360
Minnesota (1)
AreaForestAcres
Hegman LakesSuperior National Forest675
References (11)
  1. Flora of North America Editorial Committee (FNA). 2019. Flora of North America north of Mexico. Vol. 17: Magnoliophyta: Tetrachondraceae to Orobanchaceae. Oxford Univ. Press, New York. xxiv + 737 pp.
  2. Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
  3. iNaturalist. 2025. Online. Available: https://www.inaturalist.org (accessed 2025).
  4. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  5. Kearney, T.H., R.H. Peebles, and collaborators. 1951. Arizona flora. 2nd edition with Supplement (1960) by J.T. Howell, E. McClintock, and collaborators. Univ. California Press, Berkeley. 1085 pp.
  6. Native Plant Trust. 2025. Go Botany website. Online. Available: https://gobotany.nativeplanttrust.org (accessed 2025).
  7. NatureServe. 2025. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  8. Plants of the World Online (POWO). 2025. Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Online. Available: https://powo.science.kew.org/ (accessed 2025).
  9. <p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>
  10. Southwest Environmental Information Network (SEINet). 2025. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2025).
  11. Weakley, A.S., and Southeastern Flora Team. 2025. Flora of the southeastern United States Web App. Edition of February 18, 2025. University of North Carolina Herbarium (NCU), North Carolina Botanical Garden, University of North Carolina, Chapel Hill. Online. Available: https://fsus.ncbg.unc.edu (accessed 2025).