Heteranthera limosa (Sw.) Willd.

An aquatic species found in the U.S. primarily in the plains.

Plant habit at the top of Cascada de Basaseachic, Sierra Madre Occidentál, Chihuahua, Mexico, 8 Sep 2009. Photographed on a field trip with the American Penstemon Society.

A flower at the top of Cascada de Basaseachic, 8 Sep 2009.