Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

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

Cirsium ochrocentrum, Yellowspine Thistle

Ambrosia eriocentra, Woolly Bursage

Hollyleaf Bursage or Woolly Fruit Bur Ragweed has greenish almost inconspicuous flowers, male and female on the same plant (monecious). Here are female flowers that will produce the fruit, a woolly bur. Ambrosia eriocentra Hollyleaf Bursage has male and female flowers on the same plant. Here are the blooms of male (staminate) flowers just before opening. Plants bloom from April to May. Ambrosia eriocentra Hollyleaf Bursage has grayish-green to white leaves, which are attached to the branches with a very small leaf stalk (petiole) (sub-sessile). Note: bottom side of leaves lighter, almost white, than the top-side. Leaves are lanceolate and margins irregularly lobed and toothed. Ambrosia eriocentra Hollyleaf Bursage is a native species in the Sunflower or Daisy family that grows in elevations from1,500 to 5,000 feet. Habitat preferences are desert scrub, sandy soils, gravelly washes and benches along dry desert washes. Ambrosia eriocentra Hollyleaf Bursage is a perennial shrub or sub-shrub that grows up to 4 feet or more. Hollyleaf Bursage is a Mojave Desert species, locally common in Arizona with a similar distribution to White Bursage Ambrosia dumosa a close relative that is also a Mojave Desert species. Ambrosia eriocentra


Scientific Name: Ambrosia eriocentra
Common Name: Hollyleaf Bursage
Also Called: Woolly Bursage and Woolly Fruit Bur Ragweed
Family: Asteraceae, Sunflower Family
Synonyms: (Franseria eriocentra)
Status: Native
Duration: Perennial.
Size: Up to 4 feet or more.
Growth Form: Shrub, subshrub, erect woody spreading branches, rigid; stems grayish-brown, stems woolly becoming smooth with age.
Leaves: Grayish-green to white, lanceolate, margins irregularly lobed (pinnatifid-like) and toothed, short leaf stalk or petiole (sub-sessile).
Flower Color: Greenish, inconspicuous, both male (staminate) and single flowered female flowers (pistillate) (monecious) on flowering stalk (inflorescence), fruit a fusiform hairy bur about 1/3 inch long, seed is an achene.
Flowering Season: April to May.
Elevation: 1,500 to 5,000 feet.
Habitat Preferences: Desert and pinyon-juniper habitats, sandy soils, gravelly washes and benches along dry desert washes.
Recorded Range: In the United States in AZ, CA, NV and UT. In Arizona Hollyleaf Bursage is found in the central and northwestern parts of the state.

North America & US County Distribution Map for Ambrosia eriocentra.

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: Hollyleaf Bursage is a Mojave Desert species, common where found in Arizona. It has a similar distribution to White Bursage Ambrosia dumosa a close relative that is also a Mojave Desert species.

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

It is one of several Ragweed species whose pollen causes severe hay fever and allergies in some people. This species thrives in alkaline soils and has the ability to withstand very high surface temperatures for extended periods and often looks lifeless.

Date Profile Completed: 6/22/2013; Updated, 07/25/2015, updated 01/09/2017
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 eriocentra.
1993, The Jepson Manual, Citation: http://ucjeps.berkeley.edu/interchange/I_treat_indexes.html (accessed 06/22/2013)
John L. Strother, FNA | Family List | FNA Vol. 19, 20 and 21 |Asteraceae |244. Ambrosia Linnaeus, Sp. Pl. 2: 987. 1753; Gen. Pl. ed. 5, 425. 1754.; Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford.
SEINet for synonyms, scientific names and recorded geographic locations, http://swbiodiversity.org/seinet/