Identity
Unique IDELEMENT_GLOBAL.2.156265
Element CodePMCYP03E02
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
SynonymsCarex trisperma var. trisperma
Other Common NamesCarex trisperme (FR) three-seeded sedge (EN)
Concept ReferenceKartesz, 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 CommentsThis record is for the narrow treatment of Carex trisperma, excluding C. billingsii as a distinct species, as recognized by Kirschbaum (2007), Maguilla et al. (2015), and Weakley et al. (2025), and is equivalent in concept to C. trisperma var. trisperma as recognized in Kartesz (1994, 1999). Toivonen's treatment of C. trisperma in FNA (2002, vol. 23) is broader, including Carex trisperma var. billingsii as a 'reduced type.' Kirschbaum (2007) finds that geographic, ecological, morphological, and genetic data strongly suggest that what has been treated as Carex trisperma var. billingsii can be distinguished as a species.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-08-20
Change Date2000-10-22
Edition Date2025-08-20
Edition AuthorsSoteropoulos (2025)
Threat ImpactUnknown
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank ReasonsCarex trisperma is a wide-ranging perennial graminoid found in a variety of wetland habitat types, including mires, seeps, swamps, wet woods, and lowlands. It occurs in eastern and northern North America, from British Columbia and Nunavut east to Newfoundland Island, Canada, south to North Carolina, West Virginia west to Illinois, and Minnesota in the United States, and Greenland. There are over 1000 estimated occurrences, which face threats from development, cranberry farming, rights-of-way maintenance, hydrological alteration, invasive species, and other threats in some places. Little is known about trends, but with a large range extent and large number of occurrences, abundant habitat, and broad habitat preferences, this species is considered secure.
Range Extent CommentsCarex trisperma occurs in eastern and northern North America, from British Columbia and Nunavut east to Newfoundland Island, Canada, south to western North Carolina, West Virginia west to Illinois, and Minnesota in the United States, and Greenland (FNA 2002, Weakley and the Southeastern Flora Team 2025). Range extent was estimated to be approximately 9 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 CommentsBy 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 over 1000 occurrences rangewide (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).
Threat Impact CommentsAlthough threats are not widely documented, this species is threatened by development, cranberry farming, rights-of-way maintenance, hydrological alteration, 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, large number of occurrences, and affinity for typically abundant habitats.