Vegetation Around Las Vegas, Woolly Fruit Bur Ragweed (Ambrosia eriocentra)

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Woolly Fruit Bur Ragweed (Ambrosia eriocentra)
Shrubs Around Las Vegas, Vegetation Around Las Vegas

Woolly Fruit Burr Ragweed (Ambrosia eriocentra)

General: Woolly Fruit Bur Ragweed (Ambrosia eriocentra) is a medium-sized, upright composite shrub with triangular, deeply notched leaves. The flowers are yellow and in spikes. The fruit is a woolly bur with spines.

Woolly Fruit Bur Ragweed is an uncommon component of vegetation communities on well-drained sandy, gravelly, and rocky soils in washes and on upper bajadas and moderate slopes into the lower mountains in the Upper Sonoran (Mojave Desert Scrub and Pinyon-Juniper Woodland) life zones. This species is locally abundant in the wash below the Grapevine Canyon petroglyphs, but it is uncommon at Red Rocks and other places.

Family: Sunflower (Asteraceae).

Other Names: Woolly bur-sage.

Leaves deeply notched

Plant Form: Upright, evergreen shrub.

Height: Usually about 3 feet, to 6 feet.

Bark: Grayish.

Stems:

Leaves: Petioles with wings. Blades to 3.5 inches, triangular, long and narrow; deeply notched or pinnately lobed; glandular.

Flowers: Blooms in late spring. Inflorescence: spike with staminate heads above pistillate heads. Staminate flowers: many per head, yellow. Pistillate heads with 1 flower.

Ripening fruits covered in woolly hairs

Seeds: Fruit: bur to about 1/3 inch; spines; dense, long hairs. Seed: Tiny achene.

Habitat: Dry, well-drained sandy, gravelly, and rocky soils on upper bajadas and moderate slopes in the lower mountains.

Elevation: About 2,500 to 5,500 feet.

Distribution: California to southwestern Utah and northwestern Arizona.

Comments:




Leaf blades triangular and deeply notched	Leaves alternate
Woolly Fruit Burr Ragweed leaf (dorsal surface)	Woolly Fruit Burr Ragweed leaf with edges rolled-under (ventral surface)
Developing flowerhead	Male (tip of stem) and female flowers (lower on stem)
Woolly Fruit Burr Ragweed covered in ripening seeds	Woolly Fruit Burr Ragweed stem with ripening seeds
Woolly Fruit Burr Ragweed with ripening seeds	Woolly Fruit Burr Ragweed with wavy leaves and ripening seeds
Woolly Fruit Burr Ragweed with ripening seeds	Woolly Fruit Burr Ragweed with ripening seeds
Woolly Fruit Burr Ragweed with ripening seeds	More to come ...

Note: All distances, elevations, and other facts are approximate. Names generally follow the USDA database.
; Last updated 220810

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