Ambrosia monogyra, Singlewhorl Burrobrush
Scientific Name: Ambrosia monogyra
Common Name: Singlewhorl Burrobrush
Also Called: Burrobush, Burrobrush, Cheeseweed Burrobrush, Singlewhorl Burrobush; (Spanish: Jécota, Jejego, Romerillo).
Family: Asteraceae, Sunflower Family
Synonyms: (Hymenoclea monogyra)
Size: Up to 12 feet.
Growth Form: Shrub, subshrub; dark brown, brown or straw colored, erect, densely branched, broom-like in profile.
Leaves: Green; alternate, minute rough hairs (scabrous), threadlike (filiform) or linear.
Flower Color: White or green; numerous flowers, most flowers are male (staminate) with single female (pistillate) flowers in the same cluster; fruit a winged fusiform burr; seed is an achene.
Flowering Season: September to October.
Elevation: 1,000 to 4,000 feet.
Habitat Preferences: Mostly sandy soil.
Recorded Range: Singlewhorl Burrobrush is found in the southwest United States in AZ, CA, NM, NV and TX. In the states outside of Arizona it has erratic distribution apparently based on specific habitat requirements. It is marginal in NV. It is also native to Baja California and northwest Mexico. In Arizona it is locally common where found in the central, southern and western parts of the state.
North America & US County Distribution Map for Ambrosia monogyra (as Hymenoclea monogyra).
U.S. Weed Information: No data available.
Invasive/Noxious Weed Information: No data available.
Wetland Indicator: In North America Ambrosia monogyra has the following wetland designations: Arid West, UPL; Great Plains, FACW; Western Mountains, Valleys, and Coast, UPL.
UPL = Obligate Upland, almost never occur in wetlands
FACW = Facultative Wetland, usually occur in wetlands, but may occur in non-wetlands.
Threatened/Endangered Information: Listed in California as threatened because of trail usage and non-native plants.
Comments: Singlewhorl Burrobrush is a "Burrobrush" that blooms profusely in the fall. It is closely related to Cheesebush, Ambrosia salsola which also blooms profusely but in the spring. Pollen from both species causes hay fever in susceptible individuals. A predominate species where found in Arizona however, in California it is listed as threatened because of trail usage and non-native plants. In appearance it is an unlikely member of the daisy family.
Also see in Southwest Desert Flora; Canyon Ragweed, Ambrosia ambrosioides, Triangle-leaf Bursage, Ambrosia deltoidea, White Bursage, Ambrosia dumosa Hollyleaf Bursage, Ambrosia eriocentra, and Cheesebush, Ambrosia salsola.
Seeds of Singlewhorl Burrobrush were used as a food source by Seris Indians, an indigenous group of the Mexican state of Sonora. See complete species account from Native American Ethnobotany, University of Michigan, Dearborn.