First reported as introduced to North America in 2002, at a pond in northern Alabama (Reese and Haynes 2002), Rotala rotundifolia (roundleaf toothcup) has simultaneously appeared along urban canals in southern Florida. In Florida, plants display both terrestrial and aquatic growth forms and produce many small seeds within capsules. Rotala rotundifolia originates from Southeast Asia, southern India and Japan. It has been well received in the water garden trade for its brilliant, rose colored flowers and lush, creeping perennial growth. Belonging to the loosestrife family (Lythraceae), it forms expansive, colorful displays reminiscent of its cold hardy cousin, Lythrum salicaria (purple loosestrife). Rotala rotundifolia produces flowers on terminal spikes (racemes) and differs from a previously introduced species, Rotala indica, which is an annual species with shorter, lateral flower spikes. Rotala indica was introduced with rice seed and has not strayed much from rice regions of California and Louisiana. Rotala rotundifolia might be expected from a much broader range of mild climate states, if plants are found to escape from home water gardens.