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| ## screwbean {#screwbean .Title-Header}                               |
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| *Prosopis pubescens* Benth.                                           |
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| Plant Symbol = PRPU                                                   |
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Contributed by: USDA NRCS National Plant Data Center & East Bay Regional
Parks Botanic Garden

### Uses![](media/image2.png){width="2.3006944444444444in" height="1.6041666666666667in"}

*Ethnobotanic*: Various kinds of mesquite trees provided staple foods
for indigenous people of southern California, the Great Basin and the
Southwest and their seed pods are still highly relished today. Screwbean
pods were eaten by the Maricopa, Hualapai, Pima, Cahuilla, Luiseno,
Mohave, Panamint and Death Valley Shoshone, the Chemehuevi, Ute,
Gosiute, and Southern Paiute groups as far east as the edge of the
Colorado Plateau. The pods can be harvested at two different times, in
the spring, while still green and consumed raw as snacks or in the late
summer when the pods are ripe. If collected in the late summer,
traditionally they were placed in bedrock mortars or tree-stump mortars
and pounded to fine flour using stone pestles. The meal was set out to
dry and then stored in baskets in grass- or bark-lined pits in
rock-shelters or caves. Basketfuls of meal were also kept in indigenous
homes and added to cooked agave or made into small cakes. Another way to
prepare the pods was to cook the screwbeans in pits covered with earth
and left to stand three or four days, and then spread to dry. The mass
was then pounded in a mortar and the fine meal eaten as pinole.

The plant was also important medicinally. The Pima used the bark of the
root of the screwbean as a dressing for wounds. There were two ways to
prepare the dressing and then these concoctions were applied at
different times. First, the bark was boiled and the liquid applied to
the fresh wound. Second, the bark was ground up in a mortar, dried, and
again pounded into a fine meal in a metate and this powder was applied
to the wound after a few days. The Pima also used a tea made from the
roots of screwbean to regulate a woman\'s menstrual troubles. A gummy
exudate sometimes found on the bark was gathered and soaked in water and
the Moapa Paiute used the resulting liquid as eyewash. The large
branches were used in construction such as fencing and binding for large
granary baskets made by the Pima, and the Cahuilla sometimes used the
smaller branches for bows. The mescal cutter, a long pole that was used
by the Cahuilla to sever agave leaves was made of screwbean. The root
wood is good for firewood for cooking.

*Wildlife*: Screwbean is an important tree to wildlife. The seeds are
eaten by jackrabbits, Gambel quail, songbirds, various small mammals,
and domestic livestock. Western chipmunks, ground squirrels, pocket
mice, and various species of kangaroo and wood rats consume the foliage.
Different birds also nest in the tree\'s canopy. The early spring growth
also furnishes food for domestic livestock.

# Status

Please consult the PLANTS Web site and your State Department of Natural
Resources for this plant's current status, such as, state noxious status
and wetland indicator values.

![](media/image3.jpeg){width="3.4375in" height="2.2916666666666665in"}
M. Kat Anderson

USDA NRCS NPDC\
@ PLANTS

# Description

*General*: Pea Family (Fabaceae). This upright, deciduous shrub or tree
reaches up to 10 m in height. It has gnarled, shaggy multiple trunks and
forms a round spreading crown. The ascending branches have pairs of
spines that are 4-12 mm long. The compound leaves are hairy and measure
2-6 cm long, with as many as eighteen tiny leaflets per leaf. The
leaflets are arranged on the two-branched prongs of a Y-shaped leaf
stem. The yellow flowers have fused petals and are in a raceme, 4-8 cm.
and spikelike. The dark tan fruit is tightly coiled, 3-5 cm and appears
in pod clusters of 2 to 15. The pods are persistent and often exit holes
can be seen on each pod, evidence that tiny bruchid beetles have
deposited their nurseries inside. The tan seeds are very small, about 3
mm. The pollen of screwbean is toxic to honeybees. The plants
crown-sprout after injury to the trunk or after cutting.

# Distribution

For current distribution, please consult the Plant Profile page for this
species on the PLANTS Web site. This plant is uncommon in California,
found mainly in the San Bernardino Mountains and the desert. It is more
common in the southwestern United States in southern Nevada,
southwestern Utah, southern Arizona and New Mexico, western Texas and
northern Mexico in Baja California, Sonora, and Chihuahua. It is found
in creek and river bottoms, sandy/gravely washes, or ravines from
100-1300 m.

![](media/image4.jpeg){width="3.4375in" height="2.2916666666666665in"}
Steve Hurst

USDA ARS Systematic Botany

@ PLANTS

# Establishment

Gather the seed pods and take the seeds out of the pods. Some seed lots
may need scarification. Otherwise the seeds require no treatment. Plant
the seeds in a well-drained soil in deep pots. Sprinkle soil on top of
the seeds and place one-quarter inch gravel on top of the soil. The
seeds should be spaced one-half inch apart and the pots placed in
partial shade. The seeds germinate best at warm soil and air
temperatures. Water the pots right away. Keep the pots moist if the
rains are insufficient. As soon as the plants form one true leaf,
transplant one plant per pot and water. Keep the pots damp. Plant each
plant out in the ground the following winter when dormant in full sun
and well-drained soil. Protect the plants from wildlife. Water the
plants and keep them damp if the rains are insufficient. Also do some
watering in summer. Continue to water throughout the life of the plant
once in awhile. Mesquite should be lightly damp all summer long.

# Management

Screwbean can tolerate pruning and can be shaped into a small tree with
an exposed trunk or let grown naturally with the branches touching the
ground.

# Cultivars, Improved and Selected Materials (and area of origin)

This plant is available through some of the native plant nurseries
throughout its range. Contact your local Natural Resources Conservation
Service (formerly Soil Conservation Service) office for more
information. Look in the phone book under "United States Government."
The Natural Resources Conservation Service will be listed under the
subheading "Department of Agriculture."

# References

Bean L.J. & K.S. Saubel. 1972. *Temalpakh: Cahuilla Indian knowledge and
usage of plants*. Malki Museum Press, Morongo Indian Reservation,
Banning, California.

Castetter, E.F. & W.H. Bell. 1942. *Pima and Papago Indian agriculture*.
The University of New Mexico Press, Albuquerque, New Mexico

Dobyns, H.F. 1956. *Pre-conquest Hualapai plant food gather*ing. An
unpublished report to Marks and Marks, Phoenix, Arizona and Strasser,
Spielberg, Fried and Frank, Washington, D.C.

Emery, D.E. 1988. *Seed propagation of native California plants*. Santa
Barbara Botanic Garden, Santa Barbara, California

Fowler, C.S. 1986*. Subsistence*. Pages 64-97 IN: Handbook of North
American Indians. Volume 11, Great Basin. Smithsonian Institution,
Washington, D.C.

McClintock, E. 1993. *Prosopis*. Pages 641-642 IN: The Jepson Manual:
Higher Plants of California. J. Hickman (ed.). University of California
Press, Berkeley, California.

McMinn, H.E. 1939. *An illustrated manual of California shrubs*.
University of California Press, Berkeley, California.

Mielke, J. 1993. *Native* *plants for southwestern landscapes*.
University of Texas Press, Austin, Texas.

Nabhan, G.P. 1985. *Mesquite as mirror, mesquite as a harbor*. Pages
60-74 IN: Gathering the Desert. University of Arizona Press, Tucson,
Arizona.

Phillips, J. 1987. *Southwestern landscaping with native plants*. Museum
of New Mexico Press, Sante Fe, New Mexico.

Rea, A.M. 1997. *At the desert\'s green edge: An ethnobotany of the Gila
River Pima*. University of Arizona Press, Tucson, Arizona.

Shreve, F. and I.L. Wiggins 1964. *Prosopis.* Pages 602-605 IN:
Vegetation and Flora of the Sonoran Desert. Volume I. Stanford
University Press, Standford, California.

Stewart, O. 1942. *Culture element distributions 18 Ute-Southern
Paiute*. University of California Anthropological Records 4:3.

Train, P., J.R. Henrichs, & W.A. Archer 1957. *Contributions toward a
flora of Nevada No. 45: Medicinal uses of plants by Indian tribes of
Nevada.* USDA, ARS, Beltsville, Maryland.

# Prepared By & Species Coordinator

*M. Kat Anderson*

USDA, NRCS, National Plant Data Center

c/o Plant Sciences Department, University of California, Davis,
California

*Wayne Roderick*

Former Director of the East Bay Regional Parks Botanic Garden, Berkeley,
California

Edited: 05dec00 jsp; 29may03 ahv; 060808 jsp

For more information about this and other plants, please contact your
local NRCS field office or Conservation District, and visit the PLANTS
Web site\<[http://plants.usda.gov](http://plants.usda.gov/)\> or the
Plant Materials Program Web site
\<[http://Plant-Materials.nrcs.usda.gov](http://Plant-Materials.nrcs.usda.gov/)\>

*The U.S. Department of Agriculture (USDA) prohibits discrimination in
all its programs and activities on the basis of race, color, national
origin, sex, religion, age, disability, political beliefs, sexual
orientation, and marital or family status. (Not all prohibited bases
apply to all programs.) Persons with disabilities who require
alternative means for communication of program information (Braille,
large print, audiotape, etc.) should contact USDA\'s [TARGET
Center](http://www.usda.gov/oo/target.htm) at 202-720-2600 (voice and
TDD).*

*To file a complaint of discrimination write USDA, Director, Office of
Civil Rights, Room 326-W, Whitten Building, 14th and Independence
Avenue, SW, Washington, DC 20250-9410 or call 202-720-5964 (voice or
TDD). USDA is an equal opportunity provider and employer.*

*Read about [Civil Rights at the Natural Resources Convervation
Service](http://www.nrcs.usda.gov/about/civilrights/).*