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G569 Fouquieria splendens - Nolina spp. - Atriplex hymenelytra Rock Vegetation Group

Type Concept Sentence: This wide-ranging group consists of sparsely vegetated substrates from a variety of landscapes and parent material found across the southwestern U.S. and northern Mexico from rock outcrop to desert pavement with diverse and variable species composition.

Common (Translated Scientific) Name: Ocotillo - Bear-grass species - Desert-holly Rock Vegetation Group

Colloquial Name: North American Warm Semi-Desert Cliff, Scree & Pavement Sparse Vegetation

Hierarchy Level:  Group

Type Concept: This group consists of barren and sparsely vegetated substrates from a variety of landscapes across the southwestern U.S. and northern Mexico in the Chihuahuan, Sonoran, and Mojave deserts, extending south along coastal areas around the Gulf of California. Vegetation is variable depending on environmental factors of the sites, which range from sea level to subalpine elevations. Lower elevation sites often have herbaceous or shrub species present, whereas foothill, montane and subalpine sites may also include trees. Most of the species also occur in non-sparse vegetation groups. Common coastal species include Amaranthus watsonii, Eucnide rupestris, Ficus spp., Hofmeisteria spp., Nicotiana obtusifolia, Maytenus phyllanthoides, and Pleurocoronis laphamioides. In the foothills and low mountains, Bursera microphylla, Fouquieria splendens, Juniperus deppeana, Nolina bigelovii, Cylindropuntia bigelovii, and Pinus discolor are often present. On harsh shaly substrates, Atriplex hymenelytra is common. The nearly ubiquitous Eriogonum fasciculatum and Larrea tridentata are often present. High mountain cliffs and outcrops will often have scattered Abies concolor and Pseudotsuga menziesii trees growing. Nonvascular (lichens) plants are the predominant lifeform in some areas. Sites occur on a variety of landforms, including cliffs, narrow canyons, and smaller rock outcrops in desert mountains; pebbly pavement in xeric basins and alluvial fans; and upland areas around playas and washes. Geology is variable and includes igneous, sedimentary, and metamorphic rock types. Sparse vegetation also occurs on special substrates such as shale or mudstone outcrops in badlands and volcanic deposits such as tuff and basal lava. Rock substrates include bedrock and unstable talus and scree slopes in mountains. Some substrates, such as marine shales, are strongly alkaline and/or saline which chemically limits plant growth. Active substrates such as scree slopes are difficult sites for plants to grow. Physical properties of substrates may also limit plant growth. Badland sites often have heavy clay soils that reduce water infiltration increasing erosion rates and reducing soil moisture for plants.

Diagnostic Characteristics: Diagnostic characteristics of this lithomorphic group are barren to sparsely vegetated substrates and its geographic location, which is the southwestern U.S. and northern Mexico. However, it is often composed of a mix of woody vegetation, especially shrubs and herbs (particularly cushion plants), although either may be absent on a given site. Nonvascular species, especially lichens, but also mosses, are important. Current nominals for associations in this group include Aloysia wrightii, Chorizanthe rigida, Cleome isomeris, Ephedra californica, Ephedra nevadensis, Ericameria linearifolia, Geraea canescens, Pericome caudata, Perityle staurophylla, and Peucephyllum schottii.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This group is very diverse floristically and so it is difficult to determine indicator species. More diagnostic is the sparse cover of vascular plants and/or presence and sometimes dominance of nonvascular (lichen) species. This broadly defined lithomorphic group was developed by NatureServe. This probably needs to be elevated to a macrogroup, with groups identified for rockland and cliffs, pavements, and badlands or clay hills. The concept of including coastal sea cliffs needs review as those could be expected to have different floristics due to proximity of salt spray.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: This lithomorphic group may be composed of woody plants, including both trees and shrubs, herbaceous plants, and/or nonvascular plants. Shrubs are especially common and were chosen as indicator species, however, herbs (especially cushion plants) and nonvasculars such as mosses or lichens may be more common.

Floristics: Vegetation is variable depending on environmental factors of the sites, which range from sea level to subalpine elevations. Lower elevation sites often have herbaceous or shrub species present, whereas foothill, montane and subalpine sites may also include trees. Most of the species also occur in non-sparse vegetation groups. Common coastal species include Amaranthus watsonii, Eucnide rupestris, Ficus spp., Hofmeisteria spp., Nicotiana obtusifolia (= Nicotiana trigonophylla), Maytenus phyllanthoides, and Pleurocoronis laphamioides. In the deserts, foothills and low mountains, Aloysia wrightii, Bursera microphylla, Chorizanthe rigida, Cleome isomeris, Ephedra californica, Ephedra nevadensis, Ericameria linearifolia, Fouquieria splendens, Geraea canescens, Juniperus deppeana, Nolina bigelovii, Cylindropuntia bigelovii (= Opuntia bigelovii), Pericome caudata, Perityle staurophylla, Peucephyllum schottii and Pinus discolor are often present. On harsh shaly substrates, Atriplex hymenelytra is common. The nearly ubiquitous Eriogonum fasciculatum and Larrea tridentata are often present. High mountain cliffs and outcrops will often have scattered Abies concolor and Pseudotsuga menziesii trees growing. Nonvascular (lichens) plants are the predominant lifeform in some areas. Floristic information was compiled from Shreve and Wiggins (1964), Brown (1982), Barbour and Major (1988), MacMahon (1988), Dick-Peddie (1993), Sawyer and Keeler-Wolf (1995), Barbour et al. (2007), Keeler-Wolf (2007), Schoenherr and Burk (2007), and Sawyer et al. (2009).

Dynamics:  No Data Available
Environmental Description:  This group consists of barren and sparsely vegetated substrates from a variety of landscapes across the southwestern U.S. and northern Mexico in the Chihuahuan, Sonoran, and Mojave deserts, extending south along coastal areas around the Gulf of California. Landforms include cliffs, narrow canyons, and smaller rock outcrops in desert mountains; pebbly pavement in xeric basins and alluvial fans; and upland areas around playas and washes. Geology is variable and includes igneous, sedimentary, and metamorphic rock types. Sparse vegetation also occurs on special substrates such as shale or mudstone outcrops in badlands and volcanic deposits such as tuff and basal lava. Rock substrates include bedrock and unstable talus and scree slopes in mountains. Some substrates, such as marine shales, are strongly alkaline and/or saline which chemically limits plant growth. Active substrates such as scree slopes are difficult sites for plants to grow. Physical properties of substrates may also limit plant growth. Badland sites often have heavy clay soils that reduce water infiltration increasing erosion rates and reducing soil moisture for plants.
Geographic Range: This group occurs in scattered locations across the southwestern U.S. and northern Mexico in the Chihuahuan, Sonoran, and Mojave deserts extending south along coastal areas around the Gulf of California.

Nations: MX,US

States/Provinces:  AZ, CA, MXBCN, MXBCS, MXCHH, MXSON, NM, NV, TX, UT


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: GNR

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
Alliance A3143 Schott''s Pygmy-cedar - Bush Arrowleaf Scrub Alliance A3143 3.A.2.Na.6.a
Alliance A4023 Bladderpod Spiderflower - California Joint-fir - Narrowleaf Goldenbush Sparsely Vegetated Clay Flats, Hills & Badlands Alliance A4023 3.A.2.Na.6.a
Alliance A4024 Devil''s Spineflower - Hairy Desert-sunflower Desert Pavement Alliance A4024 3.A.2.Na.6.a
Alliance A4025 Wright''s Beebrush - Mountain Tail-leaf - Nevada Joint-fir Sparsely Vegetated Bedrock Cliff & Lava Field Alliance A4025 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: No Data Available
Concept Author(s): K.A. Schulz, in Faber-Langendoen et al. (2011)

Author of Description: K.A. Schulz and M.S. Reid

Acknowledgements: No Data Available

Version Date: 11-06-15
  • Barbour, M. G., T. Keeler-Wolf, and A. A. Schoenherr, editors. 2007a. Terrestrial vegetation of California, third edition. University of California Press, Berkeley.
  • Barbour, M. G., and J. Major, editors. 1988. Terrestrial vegetation of California: New expanded edition. California Native Plant Society, Special Publication 9, Sacramento. 1030 pp.
  • Brown, D. E., editor. 1982a. Biotic communities of the American Southwest-United States and Mexico. Desert Plants Special Issue 4(1-4):1-342.
  • Dick-Peddie, W. A. 1993. New Mexico vegetation: Past, present, and future. University of New Mexico Press, Albuquerque. 244 pp.
  • Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2019a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
  • Keeler-Wolf, T. 2007. Mojave Desert scrub vegetation. Pages 609-656 in: M. G. Barbour, T. Keeler-Wolf, and A. A. Schoenherr, editors. Terrestrial vegetation of California. Third edition. University of California Press, Berkeley.
  • MacMahon, J. A. 1988. Warm deserts. Pages 232-264 in: M. G. Barbour and W. D. Billings, editors. North American terrestrial vegetation. Cambridge University Press, New York.
  • MacMahon, J. A., and F. H. Wagner. 1985. The Mojave, Sonoran and Chihuahuan deserts of North America. Pages 105-202 in: M. Evenari and D. W. Goodall, editors. Ecosystems of the world 12A: Hot deserts and arid shrublands. Elsevier, New York.
  • Schoenherr, A. A., and J. H. Burk. 2007. Colorado Desert vegetation. Pages 657-682 in: M. G. Barbour, T. Keeler-Wolf, and A. A. Schoenherr, editors. 2007. Terrestrial vegetation of California. Third edition. University of California Press, Berkeley.
  • Shreve, F., and I. L. Wiggins. 1964. Vegetation and flora of the Sonoran Desert. Stanford University Press, Stanford, CA. 840 pp.