In its broad sense, this diminutive species of drying shorelines is widely scattered over the Northern Hemisphere, but several segregates have been recognized as varieties or species in North America. There are no verified records from Ky., but it is expected (BT, M). The southeastern E. americana (Pursh) Arn. was reported from Ky. by Linney (1882) but no colls. are known. The largely southwestern E. brachysperma Gray is known from c. Ill. and c. Ohio (PL) and may also be expected. Most records of the genus in southeastern states are from artificial impoundments (W; P. Cox, pers. comm.), but the plants are probably dispersed by waterfowl and may be considered native (B. Sorrie, pers. comm.).