Physiognomy and Structure: No Data Available

Floristics: Stands of this association usually occur as patches of one to several hectares within a matrix of other sandy communities dominated by Coleogyne ramosissima and Artemisia filifolia, although occasionally it will be the matrix community. The appearance is that of a grassland containing large, low-growing clonal clumps of Ephedra viridis. Total vegetation cover ranges from 5 to 55% but generally is between 15 and 35%. The vegetation is characterized by an open canopy of Ephedra viridis shrubs with between 5 and 20% cover with a well-developed grassy understory dominated by either Achnatherum hymenoides or Hesperostipa comata. The herbaceous layer totals up to 35% cover. Associated shrubs include scattered Acamptopappus sphaerocephalus, Artemisia filifolia, Atriplex canescens, Atriplex confertifolia, Coleogyne ramosissima, Ephedra torreyana, Eriogonum leptocladon, Gutierrezia microcephala, Gutierrezia sarothrae, Opuntia polyacantha var. erinacea (= Opuntia erinacea), Opuntia polyacantha var. polyacantha, Psorothamnus fremontii, Sclerocactus whipplei, and Yucca angustissima. Other grasses include Aristida purpurea, Bouteloua gracilis, Muhlenbergia pungens, Pleuraphis jamesii, Schismus barbatus, Sporobolus airoides, Sporobolus contractus, Sporobolus cryptandrus, and Vulpia octoflora (= Festuca octoflora). If Pleuraphis jamesii is present, it is with much less cover than either Hesperostipa comata or Achnatherum hymenoides. Forbs include many species typical of sandy communities, including Abronia fragrans, Ambrosia acanthicarpa, Artemisia campestris, Chaenactis stevioides, Cryptantha sp., Cymopterus newberryi, Descurainia pinnata, Eriogonum deflexum, Helianthus petiolaris, Hymenopappus filifolius, Lappula occidentalis, Machaeranthera canescens, Mentzelia multiflora, Oenothera pallida, Packera multilobata (= Senecio multilobatus), Penstemon ambiguus, Plantago patagonica, Psoralidium junceum, and Sphaeralcea parvifolia. The exotic annual tumbleweed Salsola tragus and the exotic annual grass Bromus tectorum are common in some stands. Biological soil crusts are often present and provide up to 25% cover.

Dynamics:  This association occupies deep sand deposits that have formed as dune fields on sandsheets. Although these stands are stabilized, wind erosion can pedestal plants and leave deflation basins between. Historically, these habitats were heavily grazed which, along with drought, likely activated the erosion process. Ephedra viridis is known to sprout vigorously from the roots or woody rootcrowns or establish by seed following fire (Anderson 2001b). These fire adaptations may favor it over more fire-sensitive species such as Coleogyne ramosissima.