Arizona Naturalists >>> Sonoran Desert Naturalist >>> Field Guide >>> Sonoran Desert Flora >>> Asteraceae >>> Ambrosia confertiflora

Weak-leaf Bur Ragweed

Ambrosia confertiflora

photo © by Michael Plagens

Photographed along Rackensack Wash near Camp Creek, Maricopa Co., Arizona, Oct 2009.

PERENNIAL HERB: Regrows from underground rhizomes which spread out thus forming colonies of this plant. Mostly less than ½ meter tall

LEAVES: Leaves are twice, or more, pinnately disected into narrow segments.

RANGE: In the Sonoran Desert found in canyons, near riparian habitats, in mesquite bosque openings, mostly at the higher elevations. Common also in high desert habitats such as juniper woodlands, chaparral and grasslands. Widely distributed from California east into south-central USA.

FLOWERS: Flowering may occur in late spring and again in late summer and fall depending on rainfall. The greenish flowers are not showy, but the copious pollen dispersed by the wind is responsible for hayfever symptoms in many people. On the spikes female flower heads are below the smaller exclusively male-flowered heads above.

FRUIT: The seeds are enclosed in a weak bur.

UNARMED. No thorns, burs have weak barbs.

Asteraceae -- Sunflower Family

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Copyright Michael J. Plagens, 1999-2009