Print Report

A1044 Chilopsis linearis - Psorothamnus spinosus Desert Wash Scrub Alliance

Type Concept Sentence: Mojave and Sonoran desert washes with scattered phreatophytic woody shrubs or small trees such as Acacia greggii, Chilopsis linearis, Prosopis velutina, Psorothamnus spinosus, Psorothamnus fremontii, and /or Parkinsonia florida, often in a mix of two or three of these species that are in contrast to the upland vegetation composition.

Common (Translated Scientific) Name: Desert-willow - Smoketree Desert Wash Scrub Alliance

Colloquial Name: Desert-willow - Smoketree Desert Wash Scrub

Hierarchy Level:  Alliance

Type Concept: This alliance encompasses Mojave and Sonoran desert washes with scattered woody shrubs or small trees. Indicator species are Acacia greggii, Chilopsis linearis, Prosopis velutina, Psorothamnus spinosus, Psorothamnus fremontii, and/or Parkinsonia florida. Generally several species are present, in contrast to the species found outside the wash (on the upland). Any of these may be the dominant species in terms of cover, but often several of these species are present. It is found on generally deep alluvial sands or cobbles. These stands occur in washes that are ephemeral, intermittently flooded streams and drainages that dissect bajadas, mesas and plains throughout these deserts.

Diagnostic Characteristics: Any of the following species are dominant: Acacia greggii, Chilopsis linearis, Prosopis velutina, Psorothamnus spinosus, Psorothamnus fremontii, and Parkinsonia florida.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This alliance covers washes with tall, phreatophytic species that generally have sparse cover.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Shrubland dominated by xeromorphic evergreen and/or deciduous shrubs usually less than 7 m tall. The herbaceous layer is absent to sparse.

Floristics: Stands have a 2- to 5-m tall woody layer that is dominated by the xeromorphic, cold-deciduous shrubs Acacia greggii, Ambrosia spp., Atriplex polycarpa, Baccharis pteronioides, Baccharis salicifolia, Brickellia laciniata, Chilopsis linearis, Ericameria paniculata, Fallugia paradoxa, Hymenoclea monogyra, Hymenoclea salsola, Hyptis emoryi, Indigofera lindheimeriana, Lycium spp., Olneya tesota, Parkinsonia florida, Parkinsonia microphylla, Platanus occidentalis, Prosopis glandulosa, Prosopis pubescens, Prunus fasciculata, Psorothamnus spinosus, Psorothamnus spinosus, Salix nigra, Salvia dorrii, and/or Ziziphus obtusifolia (Keeler-Wolf and Thomas 2000). The usually sparse herbaceous layer is composed of annual grasses and forbs such as Bouteloua barbata that are seasonally present. Perennial herbaceous cover is sparse, but annual grasses and forbs can be seasonally abundant. These woodlands usually occur as two strips of vegetation along the banks of a broad, sandy wash bed.

Dynamics:  These arroyo riparian shrublands are dependent on the intermittent flows/flooding of the channel to supplement soil moisture. Although many of the characteristic species can grow in the dry uplands, tree-sized versions are restricted to washes with intermittent flooding and where the plants can reach shallow water tables.
Environmental Description:  Shrublands of this southwestern desert alliance occur within and along drainages that dissect bajadas, mesas and plains in the Sonoran and Mojave deserts usually below 1600 m in elevation. They are restricted by the arid climate to washes and arroyo riparian zones and adjacent floodplains. Substrates are often sandy or gravelly alluvium and coarse-textured, but may include gravelly silty loams. The soils are generally not saline. Stands occur along the margins of washes and braided, unstable channels on bajadas, but may occur on terraces if the water table is not deep. This community is dependent on the intermittent flows/flooding of the channel to supplement soil moisture. The best examples of this community occur in lower portions of the arroyo where the streambed widens.
Geographic Range: This alliance is found in the Mojave and Sonoran deserts of southern California, northern and central Arizona, New Mexico, southern Nevada and into Mexico.

Nations: MX,US

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


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.7 North American Warm-Desert Xeric-Riparian Scrub Macrogroup M092 3.A.2.Na.7
Group 3.A.2.Na.7.a Desert-willow - Apache Plume - Desert Almond Desert Wash & Colluvial Slope Group G541 3.A.2.Na.7.a
Alliance A1044 Desert-willow - Smoketree Desert Wash Scrub Alliance A1044 3.A.2.Na.7.a
Association CEGL001164 Desert-willow Shrubland CEGL001164 3.A.2.Na.7.a
Association CEGL002701 Smoketree Shrubland CEGL002701 3.A.2.Na.7.a
Association CEGL004933 Desert-willow / Splitleaf Brickellbush Scrub CEGL004933 3.A.2.Na.7.a
Association CEGL005742 Desert-willow / (Woolly-fruit Bur-ragweed, Purple Sage) Desert Wash Scrub CEGL005742 3.A.2.Na.7.a
Association CEGL005743 Desert-willow / Mojave Rabbitbrush Desert Wash Scrub CEGL005743 3.A.2.Na.7.a
Association CEGL005744 Desert-willow / Burrobrush Desert Wash Scrub CEGL005744 3.A.2.Na.7.a
Association CEGL005745 Desert-willow / Desert Almond Desert Wash Scrub CEGL005745 3.A.2.Na.7.a
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: > Chilopsis linearis (Desert willow woodland) Alliance (Sawyer et al. 2009) [61.550.00]
> Chilopsis linearis Woodland Alliance (Evens et al. 2012)
> Chilopsis linearis Woodland Alliance (Evens et al. 2014)
> Psorothamnus spinosus (Smoke tree woodland) Alliance (Sawyer et al. 2009) [61.570.00]
> Psorothamnus spinosus Woodland Alliance (Evens et al. 2014)
> Psorothamnus spinosus Woodland Alliance (Evens et al. 2012)
>< Desert Dry Wash Woodland (#62200) (Holland 1986b)
>< Desertwillow (Plumb 1988)
? Mojave Wash Scrub (#34250) (Holland 1986b)
? Wash Woodland (Barbour and Major 1977)
Concept Author(s): J. Evens and M.S. Reid, in Faber-Langendoen et al. (2015)

Author of Description: G. Kittel and K.A. Schulz

Acknowledgements: No Data Available

Version Date: 03-14-14
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