Although omitted by Cr, this European annual has become "firmly established" at several localities in North America, especially in the midwest, and it may be increasing (FNA 23). S. mucronata is easily confused with purshiana. In Ky. it is known from some artificial ponds in PULA (KNK), where it may have been introduced with cultivated water lilies. The genus Schoenoplectiella has been recently established as a segregate of Schoenoplectus; see W for brief review of literature. It is distinguished by its rugulose achenes (versus smooth) and annual habit (versus perennial).