Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

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

Cirsium ochrocentrum, Yellowspine Thistle

Ambrosia dumosa, White Bursage

White Bursage or Burrobush has green inconspicuous flowers; male and female (monecious) intermixed on the same branches. Shown here are male flower clusters on top and upper side and female flowers looking like sharp spiny burs. Ambrosia dumosaWhite Bursage is a compact plant covered with small white hairs (tomentose) and rigid flattened straight spines (spinescent). Note both male and female flowers intermixed on terminal tips of upper branches. Ambrosia dumosa White Bursage has small leaves divided 1 to 3 times into mostly ovate or obovate divisions. Leaves are whitish in color and covered with dense white down or wool (canescent). Ambrosia dumosaWhite Bursage is one of the dominant or co-dominant species in the Sonoran and Mojave Deserts, much more so in the Mojave Desert plant communities. White Bursage thrives in poor alkaline soil conditions and is often found in open bare areas with Creosote Bushes (Larrea tridentata). Ambrosia dumosaWhite Bursage is a shrub or subshrub, very drought tolerant species that thrives in the hot dry Mojave Desert (Sonoran as well). This native species was photographed near Hyder, Yuma, County, Arizona. Ambrosia dumosa

Scientific Name: Ambrosia dumosa
Common Name: White Bursage
Also Called: Burro Weed or Burrobush (Spanish: Chicurilla, Estafiate, Ambrosia, Huizapol, Hierba del Burro, Chamizo)
Family: Asteraceae, Sunflower Family
Synonyms: (Franseria dumosa)
Status: Native
Duration: Perennial
Size: Up to 3 feet.
Growth Form: Shrub, subshrub; erect, whitish color, rounded compact shrub; spinescent.
Leaves: Leaves light gray or whitish; soft and coarse hairs, dry looking, drought-deciduous, covered soft whitish hairs (tomentose); alternate, pinnately lobed usually 3 lobed, leaves bearing rigid flattened straight spines (spinescent); new leaves in spring.
Flower Color: Green; inconspicuous flowers, male and female flowers (monecious) intermixed (male flower heads with small stem (peduncle); fruit is a roundish or spherical spiny bur, seed is an achene.
Flowering Season: April to November; March to May and December in California.
Elevation: Up to 3,000 feet; below sea level and up to 4,500 feet in California.
Habitat Preferences: Common on rocky and sandy washes, dry plains and benches

North America & US County Distribution Map for Ambrosia dumosa.

Recorded Range: In the United States, White Bursage is found in AZ, CA, NV and UT but primarily in southeast CA and western AZ. It also grows in northwest Mexico and Baja California. In Arizona it is found mostly in the western half of the state.

U.S. Weed Information: No data available.
Invasive/Noxious Weed Information: No data available.
Wetland Indicator: No data available.
Threatened/Endangered Information: No data available.

Genus Information: 25 species in Ambrosia throughout the United States and Canada. 15 species in Arizona which now includes members of the former genus Hymenoclea. Plants in the genus Ambrosia are referred to by the common name Ragweed. This species was formerly included in the genus Franseria.

Comments: Like other Ragweed, White Bursage is wind pollinated and highly allergenic to people suffering from hay fever. Ambrosia dumosa, although common throughout both the Sonoran and Mojave deserts, is much more predominant in the Mojave Desert. It thrives in alkaline soils and has the ability to withstand very high surface temperatures for extended periods and often looks lifeless.

White Bursage is one of the dominant or co-dominant species in the Sonoran and Mojave Deserts, much more so in the Mojave Desert plant communities. White Bursage thrives in poor alkaline soil conditions and is often found in open bare areas with Creosote Bushes (Larrea tridentata).

White Bursage hybridizes with Cheesebush, Ambrosia salsola. Burro Weed and Burrobush are common names also used for other southwestern plants.

Also see in Southwest Desert Flora Canyon Ragweed, Ambrosia ambrosioides, Triangle-leaf Bursage, Ambrosia deltoidea, Hollyleaf Bursage, Ambrosia eriocentra, Burrobush, Ambrosia monogyra and Cheesebush, Ambrosia salsola.

Date Profile Completed: 6/12/2014; Updated, 07/25/2015, updated 01/06/2017
References:
U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database
Arizona Flora, Kearney, Thomas H., Peebles, Robert H., 1960, University of California Press, Berkley and Los Angeles – as (Franseria dumosa).
1993, The Jepson Manual, Citation: http://ucjeps.berkeley.edu/interchange/I_treat_indexes.html (accessed 06/12/2013)
John L. Strother, FNA | Family List | FNA Vol. 21 | Asteraceae | Ambrosia, FNA Vol. 21 Page 3, 9, 10, 25, Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford.
Wikipedia contributors. "Ambrosia dumosa." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 8 Jun. 2013. Web. 12 Jun. 2013.
Marshall, K. Anna. 1994. Ambrosia dumosa. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2013, June 12].
SEINet for synonyms, scientific names and recorded geographic locations, http://swbiodiversity.org/seinet