| Echinodorus paniculatus var. paniculatus Micheli, 1881 |
| Echinodorus parvulus Engelm., 1856 |
| Echinodorus radicans (Nutt.) Engelm., 1848 |
| Echinodorus rostratus (Nutt.) Engelm., 1848 |
| Echinodorus subalatus (Mart. ex Schult. f.) Griseb., 1866 |
| Echinodorus subalatus subsp. andrieuxii (Hook. & Arn.) R.R. Haynes & Holm-Niels., 1986 |
| Echinodorus tenellus (C. Mart.) Buchenau, 1868 |
| Echinodorus tenellus var. latifolius (Seub.) Fassett, 1955 |
| Echinodorus tenellus var. parvulus (Engelm.) Fassett, 1955 |
| Echinodorus tenellus var. tenellus (C. Mart.) Buchenau, 1868 |
| Echinodorus virgatus (Hook. & Arn.) Micheli, 1881 |
| Helanthium (Benth. & Hook. f.) Engelm. ex J.G. Sm., 1905 |
| Helanthium bolivianum (Rusby) Lehtonen & Myllys, 2008 |
| Helanthium nymphaeifolium (Griseb.) Small, 1909 |
| Helanthium parvulum (Engelm.) Small, 1909 |
| Helanthium tenellum ( Mart.) Britton, 1856 |
| Hydrocleys Rich., 1815 |
| Hydrocleys nymphoides (Willd.) Buchenau, 1868 |
| Hydrocleys oblongifolia Hoehne, 1915 |
| Hydrocleys parviflora Seub., 1847 |