Carex obnupta Herbaceous Alliance
Slough sedge swards

USDA Ecological Section Map

Summary Information

  • Primary Life FormHerb
  • Elevation0-900 m
  • State RarityS3
  • Global RarityG4
  • DistributionCAN: BC. USA: CA, OR, WA (NatureServe)
  • Endemic to CaliforniaNo
  • Endemic to California Floristic Province and DesertsNo
  • Date Added2009/09/01

Characteristic Species

Carex obnupta is dominant or co-dominant in the herbaceous layer with Argentina egedii, Athyrium filix-femina, Cynosurus echinatus, Eleocharis macrostachya, Holcus lanatus, Juncus lescurii, Juncus patens, Luzula comosa, Lysichiton americanus, Sidalcea malviflora and Symphyotrichum chilense. Emergent trees and shrubs may be present at low cover, including trees Alnus rubra and shrubs:Baccharis pilularis, Morella californica, Rubus spp., Salix hookeriana and Salix lasiolepis.

Vegetation Layers

Herbs < 2 m; cover is continuous.

Membership Rules

  • Carex obnupta 50% relative cover in the herbaceous layer (Keeler-Wolf et al. 2003a).


Seasonally flooded swales in old deflation plains and sand dune complexes, shallowly inundated woods, meadows, roadside ditches, coastal swamps, lakeshores, marshes, and riverbanks. Soils are mucky with high organic content under fresh to saline water. The USFWS Wetland Inventory (1996 national list) recognizes Carex obnupta as an OBL plant.

Other Habitat, Alliance and Community Groupings

MCV (1995) Sedge series
NVCS (2009) Carex obnupta seasonally flooded herbaceous alliance
Calveg Pickleweed-Cordgrass
Holland Coastal brackish marsh, Coastal and valley freshwater marsh
Munz Coastal salt marsh, Freshwater marsh
WHR Fresh emergent wetland
CDFW CA Code 45.183.00

National Vegetation Classification Hierarchy

Formation Class Mesomorphic Shrub and Herb Vegetation (Shrubland and Grassland)
Formation Subclass Temperate and Boreal Shrubland and Grassland
Formation Temperate and Boreal Freshwater Marsh
Division Western North American Freshwater Marsh
Macro Group Western North American Freshwater Marsh
Group Vancouverian coastal/tidal marsh and meadow