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Rough Sumpweed (Iva annua)

• Family: Aster (Asteraceae)
• Flowering: July-October.
• Field Marks: Species of Iva differ from species of Ambrosia, the ragweeds, by having all the flowers the same, as opposed to ragweeds that have pollen-producing flowers in elongated spikes and pistil-producing flowers in short clusters in the axils of the leaves. Rough sumpweed differs from other species in the genus by its rough-hairy leaves.
• Habitat: Wet meadows, along streams, around ponds and lakes, fallow fields, wet prairies, roadsides.
• Habit: Annual herb with fibrous roots.
• Stems: Erect, branched, hairy, up to 6 feet tall.
• Leaves: Opposite, simple, ovate, pointed at the tip, tapering to the base or truncate, toothed, hairy, up to 5 inches long, up to 3 1/2 inches broad.
• Flowers: Many in small heads with several heads arranged in a group of crowded racemes up to 6 inches long, each head up to 1/6 inch long, subtended by narrow bracts.
• Sepals: 0.
• Petals: 5, united below into short tubes, cream-colored.
• Stamens: 5.
• Pistils: Ovary inferior.
• Fruits: Achenes dark brown, somewhat triangular, flattened, about 1/10 inch long.