Salvinia molesta is a free floating aquatic fern, made up of pairs of oval, green to brown leaves up to 1 ½” long, that are connected by a horizontal stem.  The top of each leaf has many tiny hair-like structures, that split then rejoin at the tips to form an egg beater-like structure.  Beneath the water at each node is a dissected leaf which looks like and functions as a root.  Infertile, hairy, sporocarps about 1 mm in diameter hang below the roots in long straight chains.