- Types:
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Ambrosia artemisiifolia, common ragweed
annual weed with finely divided foliage and spikes of green flowers; common in North America; introduced elsewhere accidentally
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Ambrosia trifida, great ragweed
a coarse annual with some leaves deeply and palmately three-cleft or five-cleft
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Ambrosia psilostachya, perennial ragweed, western ragweed
coarse perennial ragweed with creeping roots of dry barren lands of southwestern United States and Mexico