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Carex occidentalis

Bailey

Western Sedge

G4Apparently Secure Found in 7 roadless areas NatureServe Explorer →
G4Apparently SecureGlobal Rank
Identity
Unique IDELEMENT_GLOBAL.2.131260
Element CodePMCYP039M0
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
western 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.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2023-08-21
Change Date1990-06-04
Edition Date2023-08-21
Edition AuthorsNordman, C. (2023).
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Western Sedge (Carex occidentalis) occurs in the western United States, in the Southern Rocky Mountains from southeastern Wyoming to New Mexico, west to Utah, Nevada, Arizona, and southern California, with disjunct populations in western Wyoming, southwestern South Dakota, southwest Montana, and Idaho, and south to Mexico. There are over 300 occurrences rangewide. It is the most abundant upland sedge in New Mexico, and is considered to be common in dry forests, canyons, grasslands and along streams in Colorado.
Range Extent Comments
Western Sedge (Carex occidentalis) occurs in the western United States, in the Southern Rocky Mountains from southeastern Wyoming to New Mexico, west to Utah, Nevada, Arizona, and southern California, with disjunct populations in western Wyoming, southwestern South Dakota, southwest Montana, and Idaho (FNA 2002). Range extent was estimated to be 1.6 million square kilometers using herbarium specimens and photo-based observations documented between 1992 and 2023 (GBIF 2023, iNaturalist 2023). While not included in the Mexico checklist by Villaseñor (2016), it is included in the Cyperaceae in Mexico by González-Elizondo et al. (2018).
Occurrences Comments
Based on herbarium records, and photo-based observations documented between 1992 and 2023, and anecdotal evidence, there are over 300 occurrences rangewide (GBIF 2023, iNaturalist 2023). It is the most abundant upland sedge in New Mexico, and is considered to be common in dry forests, canyons, grasslands and along streams in Colorado (Ackerfield 2015, Allred et al. 2020).
Ecology & Habitat

Description

Western Sedge has short, creeping rootstocks and forms loose bunches with flowering stems that are sharply triangular and up to 80 cm tall. The leaves are flat with inrolled margins and 103 mm wide. The inflorescence consists of 4-10 spikes, tightly clustered towards the top but more remote at the bottom; each spike is oblong and 15-30 mm long with inconspicuous male flowers at the top. The green to straw-colored perigynia point upward in the spike; they are oblong-elliptic, 2-5 mm long, and mostly concealed by the brownish, ovate-triangular scales that have a white margin and a green center. The lens-shaped achene nearly fills the body of the perigynium.

Diagnostic Characteristics

Carex is a large genus, making individual species identification difficult at times. Mature fruit and a technical key are essential in order to separate this from closely related species.

Habitat

This species is found in dry grasslands and forests, at elevations ranging from 1200 to 3500 meters (Flora of North America Editorial Committee 2002). It is the most abundant upland sedge in New Mexico, and is considered to be common in dry forests, canyons, grasslands and along streams in Colorado (Ackerfield 2015, Allred et al. 2020).
Terrestrial Habitats
Forest/WoodlandGrassland/herbaceous
Other Nations (1)
United StatesN4
ProvinceRankNative
New MexicoSNRYes
ColoradoS4Yes
South DakotaS2Yes
NevadaS3Yes
WyomingS1Yes
North DakotaSNRYes
CaliforniaS3Yes
MontanaS1Yes
ArizonaSNRYes
TexasSNRYes
IdahoS2Yes
UtahS3Yes
Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (7)
Arizona (2)
AreaForestAcres
Cdo WsaCoronado National Forest1,955
Lower San FranciscoApache-Sitgreaves National Forests59,310
New Mexico (2)
AreaForestAcres
Hell HoleGila National Forest19,553
Sawyers PeakGila National Forest59,743
Utah (1)
AreaForestAcres
Box - Death HollowDixie National Forest3,175
Wyoming (2)
AreaForestAcres
Cow Creek MountainMedicine Bow-Routt National Forest8,276
Laramie PeakMedicine Bow-Routt National Forest28,608
References (8)
  1. Ackerfield, J. 2015. Flora of Colorado. Botanical Research Institute of Texas, Fort Worth, TX. 818 pp.
  2. Allred, K.W., E.M. Jercinovic, and R.D. Ivey. 2020. Flora Neomexicana III: An Illustrated Identification Manual, Second Edition, part 1: Introduction, spore plants, gymnosperms, monocotyledonous plants, glossary.
  3. 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.
  4. Global Biodiversity Information Facility (GBIF). 2023. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2023).
  5. González-Elizondo, M.S., Reznicek, A.A., and Tena-Flores, J.A. 2018. Cyperaceae in Mexico: Diversity and distribution. Botanical Sciences 96(2): 305-331. Online. Available: https://doi.org/10.17129/botsci.1870 (accessed 2022).
  6. iNaturalist. 2023. Online. Available: https://www.inaturalist.org (accessed 2023).
  7. 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.
  8. Villaseñor, J.L. 2016. Checklist of the native vascular plants of Mexico. Revista Mexicana de Biodiversidad 87: 559-902.