Print Report

CEGL001264 Atriplex hymenelytra - Larrea tridentata Shrubland

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Desert-holly - Creosotebush Shrubland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This shrubland association is commonly found in the Mojave Desert in Arizona, California, and Nevada, and extends in the Colorado/Sonoran Desert and southeastern Great Basin in California. It varies in shrub cover from sparse to open or intermittent (2-25% cover) and is characterized by the presence of Atriplex hymenelytra and Larrea tridentata typically dominant or codominant. Other associated shrubs at lower cover include Ambrosia dumosa, Atriplex confertifolia, Encelia farinosa, Echinocactus polycephalus, Lycium andersonii, Opuntia basilaris, Suaeda moquinii, and Tidestromia spp. If present, herbaceous cover is variable depending on precipitation, but typically sparse (<10%) with a few perennial associates present such as Castilleja angustifolia var. dubia, Chamaesyce parishii, Dalea mollissima, Eriogonum inflatum, Psathyrotes ramosissima, Sphaeralcea ambigua, Stephanomeria pauciflora, Thamnosma montana, and Xylorhiza tortifolia. Annuals may be seasonally abundant and diverse depending on season and amount of precipitation. Stands are typically found at mid to upper elevations on gravelly alluvial fans on all slope positions and less commonly on rocky colluvial slopes but can also occur at low elevations. Elevations range from 50 to 1300 m. Slopes are gentle to somewhat steep (to 25°) with typically warm easterly to southwesterly aspects. Alluvial fans are often braided with drainages and interfluves that are periodically disturbed by flows. Substrates are typically poorly developed, very gravelly, coarse-textured, alkaline soils. Soil texture is often sand or sandy loam, but less commonly includes silty clays.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association is an unusual combination of low-elevation species (Atriplex hymenelytra) and higher-elevation species (Atriplex confertifolia) together with ubiquitous Larrea tridentata and Ambrosia dumosa (Annable 1985).

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available

Floristics: This association varies in shrub cover from sparse to open or intermittent (2-25% cover) and is characterized by the presence of Atriplex hymenelytra and Larrea tridentata typically dominant or codominant (Kurzius 1981, Peterson 1984a, Annable 1985, Evens et al. 2012, 2014). Other associated shrubs at lower cover include Ambrosia dumosa, Atriplex confertifolia, Encelia farinosa, Echinocactus polycephalus, Lycium andersonii, Opuntia basilaris, Suaeda moquinii, and Tidestromia oblongifolia (Kurzius 1981, Peterson 1984a, Annable 1985, Evens et al. 2012, 2014). If present, herbaceous cover is variable depending on precipitation, but typically sparse (<10%) with a few perennial associates such as Castilleja angustifolia var. dubia (= Castilleja chromosa), Chamaesyce parishii, Chamaesyce polycarpa, Dalea mollissima, Eriogonum inflatum, Psathyrotes ramosissima, Sphaeralcea ambigua, Stephanomeria pauciflora, Thamnosma montana, and Xylorhiza tortifolia (Kurzius 1981, Peterson 1984a, Annable 1985, Evens et al. 2012, 2014). Annuals may be seasonally abundant and diverse. Common annuals may include Amsinckia tessellata, Camissonia brevipes, Chorizanthe rigida, Cryptantha angustifolia, Cryptantha maritima, Gilia cana, Gilia stellata, Mimulus bigelovii, Mohavea breviflora, Nama demissum, Oenothera deltoides, Pectocarya recurvata, Phacelia crenulata, Plantago ovata, and Rafinesquia neomexicana (Kurzius 1981, Peterson 1984a, Annable 1985, Evens et al. 2012, 2014).

Dynamics:  No Data Available
Environmental Description:  This association commonly occurs in the Mojave Desert in California, Arizona, and Nevada, and extends into the Colorado/Sonoran Desert and southeastern Great Basin in California. It is typically found at mid to upper elevations on gravelly alluvial fans on all slope positions and less commonly on rocky colluvial slopes but can also occur at low elevations (Kurzius 1981, Peterson 1984a, Annable 1985, Evens et al. 2012, 2014). Elevations range from 50 to 1300 m. Slopes are gentle to somewhat steep (to 25°) with typically warm easterly to southwesterly aspects. Alluvial fans are often braided with drainages and interfluves that are periodically disturbed by flows. Substrates are typically poorly developed, very gravelly, coarse-textured, alkaline soils. Soil texture is often sand or sandy loam but less commonly includes silty clays. Soils are usually derived from alluvium from sedimentary rocks such as sandstone and limestone, but occasionally from igneous types such as basalt, rhyolite, or tephrite (basanite), and volcanic tuft (Kurzius 1981, Peterson 1984a, Annable 1985, Evens et al. 2012, 2014).
Geographic Range: This association is commonly found in the Mojave Desert in Arizona, California, and Nevada.

Nations: US

States/Provinces:  AZ, CA, NV


Confidence Level: Low - Poorly Documented

Confidence Level Comments: No Data Available
Grank: G5

Greasons: No Data Available
Type Name Database Code Classification Code
Class 3 Desert & Semi-Desert Class C03 3
Subclass 3.A Warm Desert & Semi-Desert Woodland, Scrub & Grassland Subclass S06 3.A
Formation 3.A.2 Warm Desert & Semi-Desert Scrub & Grassland Formation F015 3.A.2
Division 3.A.2.Na North American Warm Desert Scrub & Grassland Division D039 3.A.2.Na
Macrogroup 3.A.2.Na.6 Ocotillo - Desert-holly - Watson''s Amaranth North American Rock Vegetation Macrogroup M117 3.A.2.Na.6
Group 3.A.2.Na.6.a Ocotillo - Bear-grass species - Desert-holly Rock Vegetation Group G569 3.A.2.Na.6.a
Alliance A0872 Desert-holly Scrub Alliance A0872 3.A.2.Na.6.a
Association CEGL001264 Desert-holly - Creosotebush Shrubland CEGL001264 3.A.2.Na.6.a
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Atriplex hymenelytra - Larrea tridentata - Ambrosia dumosa Association (Warren et al. 1981)
= Atriplex hymenelytra - Larrea tridentata Shrubland (Evens et al. 2014)
= Larrea tridentata - Ambrosia dumosa - Atriplex hymenelytra Shrubland (Keeler-Wolf et al. 1998a)
= Larrea tridentata - Atriplex hymenelytra (Sawyer et al. 2009) [33.010.16]
= Larrea tridentata - Atriplex hymenelytra Association (Annable 1985)
= Larrea tridentata - Atriplex hymenelytra Association (Kurzius 1981)
= Larrea tridentata - Atriplex hymenelytra Association (Peterson 1984a)
= Larrea tridentata - Atriplex hymenelytra Shrubland (Keeler-Wolf and Thomas 2000)
= Larrea tridentata - Atriplex hymenyletra Shrubland Association (Evens et al. 2012)
Concept Author(s): Western Ecology Group

Author of Description: K.A. Schulz

Acknowledgements: No Data Available

Version Date: 04-23-18
  • Annable, C. R. 1985. Vegetation and flora of the Funeral Mountains, Death Valley National Monument. California-Nevada Cooperative National Park Resources Studies Unit, National Park Service/University of Nevada Contribution 016/07. Las Vegas, NV. 188 pp.
  • Bourgeron, P. S., and L. D. Engelking, editors. 1994. A preliminary vegetation classification of the western United States. Unpublished report. The Nature Conservancy, Western Heritage Task Force, Boulder, CO. 175 pp. plus appendix.
  • Evens, J. M., D. Roach-McIntosh, and D. Stout. 2012. Vegetation descriptions for Joshua Tree National Park. Unpublished report submitted to USDI, National Park Service, Mojave Desert Inventory and Monitoring Network. California Native Plant Society, Sacramento, CA.
  • Evens, J. M., K. Sikes, D. Hastings, and J. Ratchford. 2014. Vegetation alliance descriptions for Lake Mead National Recreation Area, Death Valley National Park and Mojave National Preserve. Unpublished report submitted to USDI National Park Service, Mojave Desert Network Inventory and Monitoring Program. California Native Plant Society, Sacramento, CA.
  • Keeler-Wolf, T., C. Roye, and K. Lewis. 1998a. Vegetation mapping and classification of the Anza-Borrego Desert State Park, California. Unpublished report on file at California Natural Diversity Database, California Department Fish and Game, Sacramento.
  • Keeler-Wolf, T., and K. Thomas. 2000. Draft descriptions of vegetation alliances for the Mojave Ecosystem Mapping project. California Natural Diversity Database, California Department of Fish and Game, Sacramento.
  • Kurzius, M. 1981. Vegetation and flora of the Grapevine Mountains, Death Valley National Monument, California - Nevada. Unpublished thesis, University of Nevada, Las Vegas.
  • Leary, K. D., and P. M. Peterson. 1984. Soil analyses in relation to vegetation in the Cottonwood Mountains, Death Valley National Monument. University of Nevada Cooperative National Park Resources Studies Unit Report 036/01, Las Vegas.
  • Peterson, P. M. 1984a. Flora and physiognomy of the Cottonwood Mountains, Death Valley National Monument, California. University of Nevada Cooperative National Park Resources Studies Unit Report CPSU/UNLV 022/06. Las Vegas, NV.
  • Sawyer, J. O., T. Keeler-Wolf, and J. Evens. 2009. A manual of California vegetation. Second edition. California Native Plant Society, Sacramento CA. 1300 pp.
  • Warren, P. L., B. K. Mortensen, B. D. Treadwell, J. E. Bowers, and K. L. Reichhardt. 1981. Vegetation of Organ Pipe Cactus National Monument. Cooperative National Park Resources Studies Unit Technical Report 7. Tucson, AZ. 140 pp.
  • Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.