#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
  supertype:  weed  any plant that crowds out cultivated plants
  member of:  genus_Ambrosia
  subtype:  common_ragweed__Ambrosia_artemisiifolia  annual weed with finely divided foliage and spikes of green flowers; common in North America; introduced elsewhere accidentally
  subtype:  great_ragweed__greatragweed__Ambrosia_trifida  a coarse annual with some leaves deeply and palmately 3-cleft or 5-cleft
  subtype:  western_ragweed__westernragweed__perennial_ragweed__perennialragweed__Ambrosia_psilostachya  coarse perennial ragweed with creeping roots of dry barren lands of southwestern United States and Mexico

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