Northern Prairie Wildlife Research Center
Common Ragweed (Ambrosia artemisiifolia)
- Family: Aster (Asteraceae)
- Flowering: July-November.
- Field Marks: Most ragweeds have opposite, coarsely hairy leaves. Male and female flowers are greenish, without petals, and borne in separate heads usually on the same plant. The common ragweed differs fom all others by its much divided leaves.
- Habitat: Cultivated fields, fallow fields, roadsides, disturbed areas.
- Habit: Coarse annual with fibrous roots.
- Stems: Upright, usually much branched, smooth or hairy, up to 7 feet tall.
- Leaves: Opposite, up to 8 inches long, divided into many narrow, toothed segments, each segment pointed at the tip, smooth or hairy.
- Flowers: Crowded into small green heads in slender, elongated spikes, the heads either sterile or composed of only male or female flowers, but both sexes usually found on the same plant.
- Male Flowers: Up to 1/4 inch long, 5- or 6-lobed; stamens 5.
- Female Flowers: Borne in ellipsoid heads up to 1/3 inch long, with 4-7 projections; ovary inferior.
- Fruits: Nutlets beaked, up to 1/4 inch long, brown, with short, sharp spines.
- Notes: The uppermost leaves may sometimes be alternate. The fruits are an important food of the bobwhite quail throughout its range, but cattle have adverse effects after eating the stems and leaves. This species causes hay fever in many people.
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