The native of range of common salvinia is uncertain, but some authors have included the southeastern USA as well as Mexico, Central America, and South America.
Common salvinia is an aquatic, free-floating fern growing as an annual or short-lived perennial. It does not have true roots. Rhizomes are horizontal, float below the water surface, and bear three fronds (leaves) at each node. Two fronds are floating while one is submersed and divided into several filaments that resemble roots but do not function as true roots. Common salvinia fronds are typically small, less than 1 in (2½ cm) with smooth margins; they are mostly oval-shaped but may have heart-shaped bases. On their upper surfaces, the fronds have water repellent hairs (trichomes) that are separate at the tips, resembling finger-like projections. The fronds are green but may vary in color depending on sun, frost exposure, stress, or nutrient conditions. The sporocarps (spore-producing structures) are small, shaped like lemons, and arranged along the submersed filaments.
Dense mats of common salvinia negatively impact freshwater systems. They impede water flow and navigation and decrease light penetration and dissolved oxygen, which displaces native species. In addition, economic impacts include reduction of fishing, waterfowl hunting, kayaking, and other recreational and cultural activities.
Pham, K., R. Diaz, and J.G. Nachtrieb. 2022. Salvinias (Salvinia spp.): History and Ecology in North America. In: R.L. Winston, Ed. Biological Control of Weeds in North America. North American Invasive Species Management Association, Milwaukee, WI. NAISMA-BCW-2022-20- SALVINIAS-P. https://bugwoodcloud.org/resource/files/26406.pdf