"bitterweed" in the noun sense
1. oxtongue, bristly oxtongue, bitterweed, bugloss, Picris echioides
widespread European weed with spiny tongue-shaped leaves and yellow flowers naturalized in United States
2. ragweed, ambrosia, bitterweed
any of numerous chiefly North American weedy plants constituting the genus Ambrosia that produce highly allergenic pollen responsible for much hay fever and asthma
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