Species:
     Elodea canadensis   (Canadian waterweed)  (3 images)
     Elodea nuttallii   (Nuttall's waterweed)  (3 images)
     Najas canadensis   (Canada water-nymph)
     Najas flexilis   (wavy or nodding water-nymph)
     Najas guadalupensis ssp. guadalupensis   (southern water-nymph)