Cephalanthus occidentalis Shrubland Alliance
Button willow thickets

USDA Ecological Section Map

Summary Information

  • Primary Life FormShrub
  • Elevation5-1000 m
  • State RarityS2
  • Global RarityG5
  • DistributionUSA: AL, CA, DE, GA, IL, IN, KY, MA, MD, MO, MS, RI, TN, VA (NatureServe)
  • Endemic to CaliforniaNo
  • Endemic to California Floristic Province and DesertsNo
  • Date Added1995/11/01

Characteristic Species

Cephalanthus occidentalis is dominant in the shrub or small tree canopy with Cornus sericea, Salix exigua, Salix gooddingii and Salix lucida ssp. lasiandra.

Vegetation Layers

Shrubs < 6 m; canopy is continuous, intermittent, or open. Herbaceous layer is sparse or grassy.

Membership Rules


Seasonally flooded basins, sloughs, oxbow basins on floodplains with subsurface water at the end of the growing season. Soils are poorly aerated and fine textured. The USFWS Wetland Inventory (1996 national list) recognizes Cephalanthus occidentalis as an OBL plant.

Other Habitat, Alliance and Community Groupings

MCV (1995) Buttonbush series
NVCS (2009) Cephalanthus occidentalis seasonally flooded shrubland alliance
Calveg Willow (riparian scrub)
Holland Buttonbush scrub
Munz Not treated
WHR Valley foothill riparian
CDFW CA Code 63.300.00

National Vegetation Classification Hierarchy

Formation Class Mesomorphic Tree Vegetation (Forest and Woodland)
Formation Subclass Temperate Forest
Formation Temperate Flooded and Swamp Forest
Division Western North America Warm Temperate Flooded and Swamp Forest
Macro Group Southwestern North American Riparian, Flooded and Swamp Forest
Group Southwestern North American riparian/wash scrub