Home/Species/ Curved-spike Sedge

Carex incurviformis

Mackenzie

Curved-spike Sedge

G4Apparently Secure (G4?) Found in 1 roadless area NatureServe Explorer →

G4Apparently SecureGlobal Rank

UnknownThreat Impact

Identity

Unique IDELEMENT_GLOBAL.2.152176

Element CodePMCYP036G0

Record TypeSPECIES

ClassificationSpecies

Classification StatusStandard

Name CategoryVascular Plant

Endemicoccurs (regularly, as a native taxon) in multiple nations

KingdomPlantae

PhylumAnthophyta

ClassMonocotyledoneae

OrderCyperales

FamilyCyperaceae

GenusCarex

Other Common Names

Carex incurviforme (FR) Seaside 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) do not recognize varieties of Carex incurviformis . In contrast, Kartesz (1994) recognized two varieties, var. danaensis and the typical var. incurviformis.

Conservation Status

Rank Method Rank calculation - Biotics v2

Review Date2026-03-19

Change Date2026-03-19

Edition Date2026-03-19

Edition AuthorsEberly (2026)

Threat ImpactUnknown

Range Extent>2,500,000 square km (greater than 1,000,000 square miles)

Number of Occurrences21 - 300

Rank Reasons

Carex incurviformis is a sedge of western North America that occurs in alpine habitats of the Rocky Mountains of Canada and the United States from Alaska and Yukon Territory south through Alberta and British Columbia, Idaho, Montana, and Wyoming to Colorado and in the Sierra Nevada of California. The species is uncommon across a broad range, with potentially over 100 occurrences, nearly half of which are historical. While it occurs in remote, rugged high-elevation terrain that offers some protection from many anthropogenic disturbances, shifting habitats due to climate change remain a threat.

Range Extent Comments

Carex incurviformis occurs in western North America in alpine zones of the Rocky Mountains of Canada and the United States from Alaska and Yukon Territory south through Alberta and British Columbia, Idaho, Montana, and Wyoming to Colorado and in the Sierra Nevada of California (FNA 2002). Range extent was estimated at 4,044,518 sq km using herbarium specimens and NatureServe Network occurrence data documented between 1985 and 2025 (RARECAT 2025, GBIF 2026, NatureServe 2026, SEINet 2026). If historical data are included, range extent is estimated at 4,385,720 sq km.

Occurrences Comments

By applying a 1 km separation distance to herbarium records and NatureServe Network occurrence data documented between 1985 and 2025, it is estimated that there at least 63 occurrences rangewide (RARECAT 2025, GBIF 2026, SEINet 2026). If historical data are included, there are over 111 occurrences.

Threat Impact Comments

While it occurs in remote, rugged high-elevation terrain that offers some protection from many anthropogenic disturbances (MTNHP 2026, WYNDD 2026), shifting habitats due to climate change remain a threat, and MTNHP (2026) assesses its climate change vulnerability index as extermely vulnerable.

Ecology & Habitat

Description

Maritime Sedge is a low, perennial, grass-like plant that forms loose clumps with stems ranging from 2-10 cm high, which arise from creeping rootstocks. The leaves, which are clustered at the base, are as long or longer than the stems and ca. 1 mm wide with inrolled margins. Flowers are borne in 3-5 spikes which are densely clustered together to form a globose head subtended by papery, brown bracts. Inconspicuous male flowers occur at the top of each spike. The egg-shaped, slightly inflated perigynia, 3-5 mm long, have a short beak and spread apart as the fruit matures. The brown scales with light margins are shorter than the perigynia that they subtend. There are 2 styles, and the achene is 2-sided.

Diagnostic Characteristics

C. BREWERI and C. CAPITATA occur at high elevations, but they have solitary spikes that are not subtended by papery bracts as long as the spikes. C. DOUGLASII does not occur in subalpine or alpine habitats. C. MICROPTERA and C. HAYDENIANA have male flowers (recognized by old anthers) at the base of the spikes. A hand lens or microscope will be needed to observe these characters.

Habitat

This species occurs in alpine zones in gravels, boulder fields, rock slopes and ledges, cliffs, talus, moist meadows, and often in mossy turf or hummocks of alpine tundra, at elevations of 1,900 to 4,400 m (FNA 2002, CNDDB 2026, WYNDD 2026)

Terrestrial Habitats

Grassland/herbaceousAlpineTundraBare rock/talus/screeCliff

Other Nations (2)

CanadaN4

Province	Rank	Native
Yukon Territory	S2	Yes
Alberta	S3	Yes
British Columbia	S4	Yes

United StatesN4

Province	Rank	Native
Colorado	S3	Yes
Wyoming	S2	Yes
California	S4	Yes
Idaho	S1	Yes
Montana	S2	Yes
Alaska	S2	Yes

Threat Assessments

Threat	Scope	Severity	Timing
11 - Climate change & severe weather	Pervasive - large	Unknown	High - low
11.1 - Habitat shifting & alteration	Pervasive - large	Unknown	High - low

Plant Characteristics

DurationPERENNIAL

Economic Value (Genus)No

Roadless Areas (1)

Nevada (1)

Area	Forest	Acres
Boundary Peak (NV)	Inyo National Forest	21,851

References (9)

California Natural Diversity Database (CNDDB). 2026. RareFind Version 5.3.0. California Department of Fish and Game, Sacramento.
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.
Global Biodiversity Information Facility (GBIF). 2026. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2026).
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.
Montana Natural Heritage Program (MTNHP). 2026. Montana Field Guide. Online. Available: http://fieldguide.mt.gov (Accessed 2026).
NatureServe. 2026. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
<p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>
Southwest Environmental Information Network (SEINet). 2026. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2026).
Wyoming Natural Diversity Database (WYNDD), University of Wyoming. 2026. Wyoming Field Guild. Online. Available: https://fieldguide.wyndd.org. Accessed in 2026.

Carex incurviformis

Description

Diagnostic Characteristics

Habitat

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