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, Woolly Fruit Bur Ragweed

Family: Asteraceae, Sunflower Family

Synonyms: (Franseria eriocentra)

Status: Native

Duration: Perennial.

Size: Up to 4.9 feet (1.5 m) or more

Growth Form: Shrub; erect rounded plants; woody branches, stems brownish gray, young twigs coated in light woolly fibers, older branches are hair-less (glabrous).

Leaves: Greenish-gray to white; leaves mostly without a blade stalk (sessile) or with short blade stalk (petiole); blade shape variable, lanceolate to lance-linear or pinnately lobed; leaf edges or margins with rolled lobes or toothed edges.

Flower Color: Greenish to yellowish-green, inconspicuous, male (staminate) flowers and female (pistillate) flowers proximal to each other on flowering stalk (inflorescence); fruit is a green burr (cypsela) with long-soft silky white hairs and hairy-tufted sharp spines.

Flowering Season: April to May, June or July

Elevation: 1,500 to 5,000 feet (450-1,500 m)

Habitat Preferences: Desert and pinyon-juniper habitats, sandy soils and 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.

North America species range map for Ambrosia eriocentra:
North American range map courtesy of Virginia Tech, Dept. of Forest Resources & Environmental Conservation

North America species range map for Ambrosia eriocentra: Click image for full size map
Click image for full size map

U.S. Weed Information: Unknown
Invasive/Noxious Weed Information: Unknown
Wetland Indicator: Unknown
Threatened/Endangered Information: Unknown

Genus Information: In North America there are 25 species and 25 accepted taxa overall for Ambrosia. Worldwide, The Plant List includes 51 accepted species names and a further 81 scientific names of infraspecific rank for Ambrosia.

The genus Ambrosia was published by Carl Linnaeus in 1753.

In the Southwestern United States: Arizona has 15 species of genus, California has 14 species, Nevada and New Mexico each have 8 species, Texas and Utah each have 10 species. Data includes Hymenoclea. All data approximate and subject to revision.

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 primarily 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 soil and has the ability to withstand very high surface temperatures for extended periods and often looks lifeless.

Importance to Wildlife, Birds and Livestock
Seeds of Ambrosia eriocentra may likely be eaten by birds and small mammals.

Special Value to Native Bees, Butterflies and Insects
Ambrosia eriocentra flowers may be visited by small butterflies, bees and other small insects.

The genus Ambrosia (Ambro'sia:) from Greek for "food of the gods." The genus Ambrosia was published by Carl Linnaeus in 1753.

The species epithet "eriocentra" (eriocen'tra:) from the Greek words for "woolly" and "center, a point, spur" references to several of the species characteristics.


Date Profile Completed: 6/22/2013; updated 04/28/2020
Arizona Flora, Kearney, Thomas H., Peebles, Robert H., 1960, University of California Press, Berkley and Los Angeles, as Franseria eriocentra.
U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search - (accessed 04/22/2020) for Ambrosia, includes Hymenoclea
The Plant List (2013). Version 1.1. Published on the Internet; (accessed 04/22/2020).
David J. Keil 2012, Ambrosia eriocentra, in Jepson Flora Project (eds.) Jepson eFlora, /eflora/eflora_display.php?tid=824, accessed on April 28, 2020.
John L. Strother, FNA | Family List | FNA Vol. 19, 20 and 21 | Ambrosia | 6. Ambrosia eriocentra (A. Gray) W. W. Payne, J. Arnold Arbor. 45: 423. 1964; Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford.
Wikipedia contributors, 'Ambrosia eriocentra', Wikipedia, The Free Encyclopedia, 4 October 2019, 01:19 UTC, [accessed 28 April 2020]
SEINet synonyms, scientific names, geographic locations, general information.
Etymology: Michael L. Charters California Plant Names: Latin and Greek Meanings and Derivations; A Dictionary of Botanical and Biographical Etymology - (accessed 04/22/2020)