american common ragweed, ambrosia artemisiifolia, causing allergy.

abstract allergenic allergy ambrosia american artemisia artemisiifolia background bitter bitterweed blackweed blossom blue botany carrot climate color dangerous disease fever flower flowers green growth habitat hay illness ilness leaf macro nature neophyte plant plants pollen quarantine ragweed season sensitive sickness stammer stammerwort stem stickweed summer tassel weed wormwood wort yellow