Giant salvinias are a group of free floating ferns native to South America. Species include Salvinia molesta, S. auriculata, S. biloba and S. herzogii. They have been spread to the tropics and subtropics, moved in part by the trade in ornamental plants for fish tanks and ponds. Each plant has an internode, a node, a pair of floating leaves, the submerged or root, and associated buds. The root is actually a modified leaf that looks and functions like a root.
Foliage
Giant salvinias have a horizontal rhizome just beneath the water surface. On the abaxial leaf surface are hairs that are divided but joined at the tips of the hairs. These hairs have an egg-beater-like appearance.
Reproduction
Giants salvinias reproduce by buds, both apical and axillary.
Ecological Threat
Giant salvinia forms dense mats over lakes and slow moving rivers and causes large economic losses and a wide range of ecological problems to native species and communities. It can impede access to and use of waterways for commercial and recreational purposes. Mats of giant salvinia can reduce habitats for game birds and limit access to fishing areas. Salvinia can clog water intake pipes and interfere with agricultural irrigation and water supply.