Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

Home to the plants of the Sonoran, Chihuahuan and Mojave Deserts

Cirsium ochrocentrum, Yellowspine Thistle

Prosopis pubescens, Screw Bean Mesquite

Prosopis pubescens, Screw Bean Mesquite, Southwest Desert Flora Prosopis pubescens, Screw Bean Mesquite, Southwest Desert Flora Prosopis pubescens, Screw Bean Mesquite, Southwest Desert Flora Prosopis pubescens, Screw Bean Mesquite, Southwest Desert Flora

Scientific Name: Prosopis pubescens
Common Name: Screw Bean Mesquite
Also Called: Screwbean, Screwpod Mesquite (Spanish: Tornillo, Mezquite Tornillo)
Family: Fabaceae or Leguminosae Family
Synonyms: (Strombocarpa odorata)
Status: Native
Duration: Perennial
Size: Up to 20 feet.
Growth Form: Tree or shrub; the crown is more narrow than full, branches ascending, spines present.
Leaves: Green; pubescent, pinnately compound.
Flower Color: White, yellow; flowers in spikes about 3 inches long, fruit a showy tightly coiled legume.
Flowering Season: May to June.
Elevation: Below 4,000 feet

Habitat Preferences: Lower flood plains, creek bottoms, gravelly washes and sandy or saline soils.

Recorded Range: In the United States, Screw Bean Mesquite is found in the southwest in the states of; AZ, CA, NM, NV, TX and UT. It is also native to northern Mexico and possibly northern Baja California.

North America & US County Distribution Map for Prosopis pubescens.

U.S. Weed Information: No information available.

Invasive/Noxious Weed Information: All members of the genus Prosopis are listed as a Noxious Weed by the state of Florida.

Wetland Indicator: In North America Prosopis pubescens has the following wetland designations; Arid West, FAC; Great Plains, FAC; Western Mountains, Valleys, and Coast, FAC
FAC, Facultative, occur in wetlands and non-wetlands.

Threatened/Endangered Information: Arizona Screw Bean Mesquite is "Salvage Assessed", "Harvest Restricted". A permit is needed from the Department of Agriculture to transport this species off of private land.

Genus Information: 35 species in Prosopis in the southwestern United States. 3 native species in Arizona.

The Plant List includes 111 scientific plant names of species rank for the genus Prosopis. Of these 46 are accepted species names.

Comments: Screw Bean Mesquite may be a dominant species lower elevation riparian areas or mesquite bosque habitats. The flowers provide an important source of nectar for desert honey-bees and wildlife and livestock eagerly eat the leaves and sweet pods or Screw Bean Mesquite.

All species of Mesquite make excellent firewood and their wood has been used for tool handles and fence-posts. Pollen from all species are reported to be responsible for hay-fever.

Also see in Southwest Desert Flora; Western Honey Mesquite, Prosopis juliflora var. torreyana.

The fruit pods and seeds have been used for earache or ground into flour and made into bread by southwestern Native Americans. See ethno-botanical uses at Native American Ethnobotany, University of Michigan, Dearborn.

Date Profile Completed: 09/06/2015, updated, 09/14/2015, updated format 10/12/2017
U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search
Arizona Flora, Kearney, Thomas H., Peebles, Robert H., 1960, University of California Press, Berkley and Los Angeles, California.
Native Plant Information Network, NPIN (2013). Published on the Internet [accessed: 09/06/2015]. Lady Bird Johnson Wildflower Center at The University of Texas, Austin, TX.
USDA Forest Service Fire Effects Information System (MEOF);; (accessed 09/06/2015)
1993, The Jepson Manual, Citation: (accessed 09/06/2015),4179,4181
The Plant List (2013). Version 1.1. Published on the Internet; (accessed 09/06/2015).
SEINet for synonyms, scientific names, recorded geographic locations and general information