Ambrosia ambrosioides, Ambrosia Leaf Bur Ragweed, Southwest Desert Flora

Ambrosia ambrosioides, Canyon Ragweed

Canyon Ragweed or Big Bursage is a native perennial that may grow up to 6 feet or more in a season. In the southwest it grows at elevations up to 4,500 feet. Ambrosia ambrosioides

Canyon Ragweed is a tall subshrub or shrub with multiple stems with bristly white hairs and reddish-brown stems. Stem scars are quite typical. Ambrosia ambrosioides

Canyon Ragweed has alternate, lanceolate or narrowly triangular dark green leaves. Leaves are dramatic looking, up to 8 inches or more long, hairy and sticky with sharply toothed margins. Ambrosia ambrosioides

Canyon Ragweed has dull yellow or yellowish-green inconspicuous male and female flowers on the same plants. Here male flowers grow terminally on branches, each with its own small stem (peduncle). Ambrosia ambrosioides

Canyon Ragweed has dull yellow or yellowish-green inconspicuous male and female flowers on the same plants. Female flowers grow in clusters on lateral axils just below the male flowers. Here is the developing fruit, a young green bur, from a female flower. Ambrosia ambrosioides

Scientific Name: Ambrosia ambrosioides
Common Name: Ambrosia Leaf Bur Ragweed

Also Called: Ambrosia Bursage, Big Bursage, Canyon Ragweed (Spanish: Chicura).

Family: Asteraceae, Sunflower Family

Synonyms: (Franseria ambrosioides, Xanthidium ambrosioides)

Status: Native

Duration: Perennial.

Size: 2 to 5 feet (60-150+ cm) tall, or more.

Growth Form: Subshrub or Shrub; multiple stems erect; stems covered with minute soft erect hairs (puberulous), sticky sap from glandular hair; plants aromatic.

Leaves: Dark green; leaves large, up to 8 inches; leaves with long stalks (petioles); leaves alternate; shape lanceolate to narrowly triangular; leaf edges (margins) coarsely toothed, strongly veined below, leaves with dotted with sticky glands.

Flower Color: Dull yellow or yellowish-green; inconspicuous, male and female flowers (bisexual); the male and female flowers are grouped together in separate locations on the flowering stems (inflorescence), the male or staminate flowers are located on an unbranched flowering stem in a raceme, while the female or pistillate flowers are proximal to the male flowers; fruit a small fusiform burr with spines and slightly hooked beaks.

Flowering Season: March to May

Elevation: 500 to 4,000 feet (150-1,200 m)

Habitat Preferences: Riparian areas, sandy soils, washes, canyons, disturbed areas and sandy or gravelly river bottoms; California, in coastal scrub and disturbed areas.

Recorded Range: Ambrosia Leaf Bur Ragweed or Canyon Ragweed is relatively rare in the United States occurring in California but mostly in Arizona. It is also native to southern Baja California and Mexico (Chihuahua, Durango, Sonora). In Arizona, Canyon Ragweed is found in central, southern and western parts of the state.

North America & US County Distribution Map for Ambrosia ambrosioides.

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

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: Ambrosia Leaf Bur Ragweed or Canyon Ragweed is limited in distribution in the United States to Arizona and California. It is common throughout much of Arizona but is limited to San Diego County in California. Ambrosia Leaf Bur Ragweed is one of several Ragweed species whose pollen causes hay fever and allergies in some people.

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

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

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

Etymology: 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 "ambrosioides" (ambrosio'ides:) means like the genus Ambrosia.

Ethnobotany Ambrosia ambrosioides has been used as an analgesic for respiratory problems by Western American indigenous peoples.

Pima Drug, Gynecological, Analgesic and Antihemorrhagic; Decoction of crushed roots taken by women for pains and menstrual hemorrhage.

Pima Drug, Cough Medicine; Poultice of warmed leaves applied to the chest to loosen a cough

See ethno-botanical uses at Native American Ethnobotany, University of Michigan, Dearborn.