Name:
Hesperostipa comata Bunch Herbaceous Alliance
Reference:
Western Ecology Working Group of...
Description:
This grassland alliance is found on sandy soils in the intermountain steppe, Wyoming Basin, Colorado Plateau, Great Basin and Columbia Plateau. Stands typically occur on upland sites with coarse-textured soils such as sandstone outcrop ridges in the plains, dry-sandy sites in the Columbia Basin, and parks on dissected alluvial fans below sandstone plateaus, but not dunes. Sites are on flat to moderately steep, often south-facing slopes, but can occur on any aspect. Soils are shallow to moderately deep, well-drained, coarse-textured, and non-saline. Grasslands included in this alliance are characterized by a moderately dense herbaceous layer dominated by Hesperostipa comata (= Stipa comata), but cover ranges from sparse to dense. Achnatherum hymenoides (= Oryzopsis hymenoides) or Poa secunda codominate some stands. Other graminoids may include Aristida purpurea, Bouteloua gracilis, Carex filifolia, Koeleria macrantha, Pleuraphis jamesii (= Hilaria jamesii), or Sporobolus cryptandrus. Shrubs and dwarf-shrubs are sparse (<10%) and may include scattered Artemisia cana, Artemisia frigida, Artemisia tridentata, or Ericameria nauseosa (= Chrysothamnus nauseosus). Forb cover is also sparse, but can be relatively diverse. Common forbs are Gaura coccinea, Lappula occidentalis (= Lappula redowskii), Lithophragma glabrum, Lupinus pusillus, Opuntia aurea (= Opuntia basilaris var. aurea), Opuntia polyacantha, Plantago patagonica, or Pediomelum argophyllum (= Psoralea argophylla). Cryptogams are important in some stands with up to 40% ground cover on sites in the Colorado Plateau. Diagnostic of this grassland alliance is the dominance of Hesperostipa comata in the herbaceous layer and the lack of significant cover of Bouteloua gracilis or Nassella viridula.
Accession Code:
VB.CC.20501.HESPEROSTIPACOM
Plot-observations of this Community Concept:
0
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