Other names: Great ragweed, horseweed
Life cycle: Summer annual
Found in: Cropland throughout the U.S. except the Pacific Coast and parts of the Southwest, Florida and Maine.
General description: Erect plant with hairy stems. Can grow up to 16 feet and thrives in fertile soils.
Seedlings: Cotyledons are round, thick and fairly large. Hypocotyl is usually purple.
True leaves: Opposite, hairy and three-lobed or five-lobed. Lobes arise from the same point and have toothed edges. Leaves are 4" to 8" wide by 6" long.
Flowers and fruit: Flowers are small and green and bloom on slender stems at the ends of branches or on the bases of upper leaves. Fruit is large, dry, black and crown-shaped.
Special note: Exhibits glyphosate resistance.