This floating aquatic weed has spread from tropical regions to warmer regions of southeastern states. There are a few colls. from western regions of Ky., but the plants probably cannot persist and spread unless winters become milder (W). The record from JEFF (BT, M) was erroneous, apparently being based on a coll. at DHL (APSC) from Jefferson Co., Texas. See W for notes on generic name; Oshuna is monotypic.