Name honors Antonio Maria Salvini, 1633-1729, Italian professor of Greek who helped the original botanists who worked with this genus.

Plants small, free-floating on water. Stems creeping near water surface, producing clusters of blades at nodes, bearing hairs but no true roots. Blades in floating clusters of 3:2 short-stalked to sessile, ovate to cordate, horizontally spreading, green, upper surfaces (the true abaxial surfaces) covered with water-repellent hairs, with shoots and lower surfaces of floating blades bearing uniseriate, multicellular, pointed hairs (this hair type also present on the submerged blades), and 1 submerged leaf, this stalked, finely dissected, and acting as a cluster of roots. Veins obscure. Sori surrounded by globose indusia producing sporocarps borne in linear clusters on branches of submerged blades.

A genus of about ten mostly tropical species naturally occurring in America as far north as the southern United States, Africa, Madagascar, and Europe and eastward to India, China, Sumatra, Manchuria, and Japan. Represented in Hawai 'i by one recently naturalized, very aggressive species that has raised havoc in other parts of the world where it has been introduced.

The reproductive life of Salvinia species differs from that of most other fern families that produce only small spores. Sporocarps producing megaspores (female) and microspores (male) are formed. The microspores germinate inside the sporangium, and prothalli emerge through their wall as fine tubes, at the end of which antheridia (producing sperm) form. The megaspores produce prothalli bearing archegonia (producing ova). The ornamentation of the surface of the megaspores helps in identification of the Salvinia species.