Water fern

Water fern is a common name for several plants and may refer to:
 * Salviniales, an order of aquatic ferns
 * Austroblechnum lanceolatum, syn. Blechnum chambersii, lance water fern
 * Austroblechnum patersonii, syn. Blechnum patersonii, or strap water fern
 * Austroblechnum penna-marina, syn. Blechnum penna-marina, or alpine water fern
 * Azolla filiculoides
 * Bolbitis heudelotii, or African water fern
 * Cranfillia fluviatilis, syn. Blechnum fluviatile, or ray water fern
 * Histiopteris incisa
 * Lomaria nuda, syn. Blechnum nudum, or fishbone water fern
 * Oceaniopteris cartilaginea, syn. Blechnum cartilagineum, or soft water fern
 * Osmunda regalis
 * Parablechnum wattsii, syn. Blechnum wattsii, or hard water fern
 * Regnellidium diphyllum, or two-leaf water fern
 * Salvinia molesta, or giant water fern
 * Telmatoblechnum indicum, syn. Blechnum indicum, or swamp water fern