Carex oligosperma

Michx.

Few-seed Sedge

G5Secure Found in 5 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.156566
Element CodePMCYP039Q0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassMonocotyledoneae
OrderCyperales
FamilyCyperaceae
GenusCarex
Other Common Names
Carex oligosperme (FR) Few-fruited Sedge (EN) Few-seeded Sedge (EN) fewseed sedge (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.
Taxonomic Comments
FNA (2002, vol. 23) and Weakley and the Southeastern Flora Team (2025) do not recognize varieties of Carex oligosperma.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-07-14
Change Date2010-01-31
Edition Date2025-07-14
Edition AuthorsSoteropoulos (2025)
Threat ImpactUnknown
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Carex oligosperma is a wide-ranging perennial graminoid found in a variety of open wetland habitats, including bogs, poor fens, seeps, open swamps, marshes, lakeshores, and riverbanks. It occurs in eastern North America from Newfoundland Island and Nova Scotia west to Nunavut, Alberta, and the Northwest Territories, Canada south in the United States to Connecticut west to Minnesota, and disjunct southwards at high elevations in West Virginia and North Carolina. There are approximately 900 occurrences, which face threats from development, oil sands extraction, rights-of-way maintenance, hydrological alteration, succession, and invasive species. Little is known about trends, but with a large range extent and large number of occurrences, this species is considered secure.
Range Extent Comments
Carex oligosperma occurs in eastern North America from Newfoundland Island and Nova Scotia west to Nunavut, Alberta, and the Northwest Territories (historic), Canada south in the United States to Connecticut (historic), central Pennsylvania, northern Ohio, northern Indiana west to Minnesota, and disjunct southwards at high elevations in northeastern West Virginia and western North Carolina (FNA 2002, Weakley and the Southeastern Flora Team 2025). Range extent was estimated to be approximately 6.5 million square kilometers using herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented 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 approximately 900 occurrences rangewide (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).
Threat Impact Comments
Although threats are not widely documented, this species is threatened by development, oil sands extraction, rights-of-way maintenance, hydrological alteration, succession, invasive species, and other threats in some places, though there is insufficient data, including anecdotal accounts, to understand scope and severity of threats for this species (NatureServe 2025). However, their overall impact is likely negligible given the species' broad range and large number of occurrences.
Ecology & Habitat

Habitat

Carex oligosperma grows in "bogs, often forming extensive stands in Sphagnum-dominated areas, poor fens, sometimes in acidic, sandy, or peaty soils in open swamps, marshes, lakeshores, riverbanks," and "seeps, at high elevations in the southern Appalachian mountains, abundant but local in temperate and boreal peatlands further northward" (FNA 2002, Weakley and the Southeastern Flora Team 2025).
Palustrine Habitats
HERBACEOUS WETLANDBog/fenRiparian
Other Nations (2)
United StatesN5
ProvinceRankNative
WisconsinSNRYes
IndianaS3Yes
MinnesotaSNRYes
VermontS2Yes
MassachusettsS2Yes
MaineSNRYes
West VirginiaS1Yes
PennsylvaniaS2Yes
IllinoisS1Yes
OhioS2Yes
North CarolinaS1Yes
MichiganSNRYes
New YorkS4Yes
New HampshireSNRYes
ConnecticutSHYes
CanadaN5
ProvinceRankNative
SaskatchewanS4Yes
AlbertaS3Yes
New BrunswickS5Yes
OntarioS5Yes
Yukon TerritorySHYes
Nova ScotiaS5Yes
LabradorS5Yes
ManitobaS3Yes
Island of NewfoundlandS5Yes
QuebecS5Yes
NunavutS2Yes
Threat Assessments

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (5)
Minnesota (2)
AreaForestAcres
Hegman LakesSuperior National Forest675
Phantom LakeSuperior National Forest6,521
New Hampshire (2)
AreaForestAcres
Pemigewasset ExtWhite Mountain National Forest15,840
Sandwich RangeWhite Mountain National Forest16,797
Wisconsin (1)
AreaForestAcres
09012 - Round Lake Study AreaChequamegon-Nicolet National Forest3,707
References (8)
  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. 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. NatureServe. 2025. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  6. <p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>
  7. Southwest Environmental Information Network (SEINet). 2025. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2025).
  8. 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).