#waterweed  a weedy aquatic plant of genus Elodea
  supertype:  aquatic_plant__aquaticplant__water_plant__waterplant__hydrophyte__hydrophytic_plant__hydrophyticplant  a plant that grows partly or wholly in water whether rooted in the mud, as a lotus, or floating without anchorage, as the water hyacinth
  member of:  genus_Elodea
  subtype:  Canadian_pondweed__Elodea_canadensis  North American; widely naturalized in Europe
  subtype:  dense-leaved_elodea__Elodea_densa__Egeria_densa  aquatic plant with deep green foliage useful to oxygenate an aquarium; sometimes placed in genus Egeria

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