Giant Salvinia: Salvinia molesta
Giant salvinia is an aquatic fern prohibited in the United
States by Federal law.
||Oblong floating leaves, 1/2 to 1 1/2 inches long. Young plants
have smaller leaves that lie flat on the water surface. As plants
mature and aggregate into mats, leaves are folded and compressed
into upright chains.
Leaf surfaces have rows of cylindrical hairs topped with four
branches that are joined at the tips to form a "cage" (view with
hand lens). These hairs give a velvety appearance and repel water.
Distinguish from common salvinia, Salvinia minima, which has leaf
hairs with branches always free at the tips.
||Underwater root-like structures conceal stalks with egg-shaped
spore cases attached. Spore cases are not found on young
Currently invading sites in Texas and
Louisiana, giant salvinia has the potential to infest aquatic
habitats, wetlands and rice fields across the South. Native
to South America, its introduction by humans has caused severe
economic and ecological problems in many countries including New
Zealand, Australia and South Africa.
Help protect our aquatic resources, watch out for and report
Giant salvinia may be introduced with aquarium or water garden
plants. If you have seen this plant in cultivation or in the wild,
please contact the Nonindigenous Aquatic Species Toll Free
In Texas, call - Texas Parks and Wildlife Department at
In Florida, call - Florida Department of Environmental
Protection at 850-488-5631.
Giant salvinia grows rapidly to cover the surface of
lakes and streams, spreading aggressively by vegetative fragments.
It forms floating mats that shade and crowd out important native
plants. Thick mats reduce oxygen content and degrade water quality
for fish and other aquatic organisms. Mats impede boating, fishing,
and swimming and clog water intakes for irrigation and electrical
Salvinia (Salvinia molesta)
Image Credit: R. Helton, Texas Parks and Wildlife Department Design and Production: Texas Sea Grant College Program