Cyperus bipartitus

Torr.

Shining Flatsedge

G5Secure Found in 2 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.154462
Element CodePMCYP063U0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassMonocotyledoneae
OrderCyperales
FamilyCyperaceae
GenusCyperus
Synonyms
Cyperus rivularisKunthPycreus bipartitus(Torr.) C.B. Clarke
Other Common Names
slender flatsedge (EN) Slender Flatsedge (EN) Souchet des rivières (FR)
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 Date2025-07-24
Change Date1993-07-08
Edition Date2025-07-24
Edition AuthorsSkello, M. (1993), rev. Johnson, J. (2025)
Threat ImpactUnknown
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Cyperus bipartitus is an annual graminoid that is native to much of North, Central, and South America. With a large range extent, more than 1200 occurrences, abundant habitat, and broad habitat preferences, this species is considered secure.
Range Extent Comments
Cyperus bipartitus is native to much of the United States and southern Canada, extending south through Central America to central South America as far south as northern Argentina (POWO 2025). In the United States, Cyperus bipartitus is common in the eastern and Pacific northwest states but sparse in the desert southwest and absent from the northern Great Plains and Rocky Mountains (FNA 2002). Range extent was estimated to be 34 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 more than 1200 occurrences rangewide (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).
Threat Impact Comments
Although threats are not widely documented, Cyperus bipartitus is potentially threatened by development, road maintenance, invasive species, and other threats in some places. However, their overall impact is likely negligible given the species' broad range, large number of occurrences, tolerance of light disturbance, and affinity for typically abundant habitats.
Ecology & Habitat

Description

Shining Flatsedge is a grass-like annual which forms tufts of slender stems that are 5-20 cm high. The few leaves occur near the base of the plant and are 1-2 mm wide. The flowers consist of a small, blunt scale with a pale, ca. 2-3 mm long midrib, which subtends a single stamen and ovary. The flowers are crowded opposite each other into flattened spikelets that are 3-15 mm long. Spikelets occur in open clusters borne on very short to long stalks arising from the stem tips. The inflorescence is subtended by 2-4 leaf-like bracts, at least one of which is longer than the inflorescence. The seed is lens-shaped.

Diagnostic Characteristics

C. ACUMINATUS, C. ARISTATUS, and C. ERYTHRORHIZOS all have scales with pointed or short, awn-tipped scales.

Habitat

Cyperus bipartitus grows in wet ground, especially along shores, margins of streams, marshes, shores of ponds, lakes, bogs, low fields, ditches, and disturbed places (Godfrey and Wooten 1981, FNA 2002).
Terrestrial Habitats
Grassland/herbaceous
Palustrine Habitats
HERBACEOUS WETLANDBog/fenRiparian
Other Nations (2)
CanadaN5
ProvinceRankNative
QuebecS3Yes
New BrunswickS2Yes
OntarioS5Yes
United StatesN5
ProvinceRankNative
North CarolinaS4Yes
NevadaSNRYes
GeorgiaS5Yes
MississippiS1Yes
New MexicoSNRYes
MarylandSNRYes
OklahomaSNRYes
District of ColumbiaSNRYes
MichiganSNRYes
FloridaSNRYes
WyomingS1Yes
IllinoisS4Yes
MontanaS1Yes
TennesseeSNRYes
MassachusettsSNRYes
WisconsinSNRYes
TexasSNRYes
New JerseyS4Yes
UtahS1Yes
DelawareS4Yes
NebraskaSNRYes
North DakotaS2Yes
CaliforniaSNRYes
MinnesotaSNRYes
New YorkS5Yes
Rhode IslandSNRYes
OregonS3Yes
KansasS3Yes
PennsylvaniaS5Yes
IndianaS5Yes
ConnecticutSNRYes
AlabamaSNRYes
IdahoS3Yes
West VirginiaS5Yes
MaineSNRYes
ColoradoS2Yes
WashingtonS3Yes
South CarolinaS2Yes
ArizonaSNRYes
New HampshireSNRYes
VirginiaS5Yes
VermontS5Yes
OhioSNRYes
South DakotaSNRYes
ArkansasSNRYes
MissouriSNRYes
KentuckyS4Yes
IowaS4Yes
Threat Assessments
ThreatScopeSeverityTiming
Unknown/undeterminedUnknownUnknownUnknown

Plant Characteristics
DurationANNUAL
Economic Value (Genus)No
Roadless Areas (2)
Michigan (1)
AreaForestAcres
FibreHiawatha National Forest7,432
Minnesota (1)
AreaForestAcres
Cabin CreekSuperior National Forest6,071
References (9)
  1. Flora of North America Editorial Committee (FNA). 2002b. Flora of North America north of Mexico. Vol. 23. Magnoliophyta: Commelinidae (in part): Cyperaceae. Oxford Univ. Press, New York. xxiv + 608 pp.
  2. Gleason, H.A., and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. New York Botanical Garden, Bronx, New York. 910 pp.
  3. Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
  4. Godfrey, R.K., and J.W. Wooten. 1981. Aquatic and wetland plants of southeastern United States: Dicotyledons. Univ. Georgia Press, Athens. 933 pp.
  5. iNaturalist. 2025. Online. Available: https://www.inaturalist.org (accessed 2025).
  6. 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.
  7. 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).
  8. <p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>
  9. Southwest Environmental Information Network (SEINet). 2025. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2025).