Poa secunda - Muhlenbergia richardsonis - Carex douglasii Herbaceous Alliance
Onesided bluegrass - mat muhly - Douglas' sedge moist meadow

USDA Ecological Section Map

Summary Information

  • Primary Life FormHerb
  • Elevation900-4000 m
  • State RarityS3
  • Global RarityG4?
  • DistributionCAN: AB, BC, MB, NB, NT, ON, QC, SK, YT. USA: AK, AZ, CA, CO, ID, ME, MI, MN, MT, ND, NE, NM, NV, OR, SD, UT, WA, WI, WY. Mexico (TJM2) (USDA Plants)
  • Endemic to CaliforniaNo
  • Endemic to California Floristic Province and DesertsNo
  • Date Added2016/07/21

Characteristic Species

Carex douglasii, Muhlenbergia richardsonis and/or Poa secunda is dominant or co-dominant in the herbaceous layer with Achnatherum hymenoides, Achnatherum pinetorum, Astragalus whitneyi, Carex filifolia, Carex rossii, Hulsea algida, Ivesia muirii, Leptosiphon nuttallii, Linanthus pungens, Lotus purshianus, Microsteris gracilis, Monardella odoratissima, Penstemon heterodoxus or Penstemon speciosus.

Vegetation Layers

Herbs < 60 cm; cover is open to continuous.

Membership Rules

  • Stands dominated by low, freshwater emergent vegetation, including Carex douglasii, Juncus articus spp. littoralis (=Juncus balticus), or Juncus mexicanus (Evens et al. 2014).
  • Carex douglasii or Muhlenbergia richardsonis > 50% relative cover in stands, occuring in moist to dry, often alkaline meadows at higher elevations. (Reyes et al. 2020a).
  • Poa secunda ssp. juncifolia has the highest cover in the herbaceous layer and co-occurs with a variety of species, such as Distichlis spicata and Juncus arcticus, on alkaline soils (VegCAMP 2014b).


Drier fringes of moist meadows, valley bottoms with shallow water tables, inactive floodplains, terraces, dry basins, in swales, on upland gentle slopes and drainage bottoms. Soils are sandy to clay loams and vary in pH, though are often alkaline. The USFWS Wetland Inventory recognizes Carex douglasii as a FACU (1996 list) and FAC (2012 list) plant, Poa secunda as a FACU (1996 and 2012 list) plant, and Muhlenbergia richardsonis as a and FAC* (1996 and 2012 list) plant.

Other Habitat, Alliance and Community Groupings

MCV (1995) Montane meadow habitat, One-sided bluegrass series, Sedge series
NVCS (2009) Carex douglasii herbaceous alliance, Poa secunda seasonally flooded herbaceous alliance
Calveg Alkaline mixed grasses and forbs, Wet grasses and forbs, Perennial grasses and forbs
Holland Dry montane meadow, Dry subalpine or alpine meadow, Alkali meadow
Munz Sagebrush scrub, Subalpine forest
WHR Alpine dwarf-shrub, Perennial grassland, Wet meadow
CDFW CA Code 41.279.00

National Vegetation Classification Hierarchy

Formation Class Mesomorphic Shrub and Herb Vegetation (Shrubland and Grassland)
Formation Subclass Temperate and Boreal Shrubland and Grassland
Formation Temperate Grassland, Meadow, and Shrubland
Division Vancouverian and Rocky Mountain Grassland and Shrubland
Macro Group Western Cordilleran Montane Shrubland and Grassland
Group Western Cordilleran montane moist graminoid meadow