What is "sagittaria"

Sagittaria is a genus of about 30 species of aquatic plants whose members go by a variety of common names, including arrowhead, duck potato, katniss, Omodaka (沢瀉 in Japanese), swan potato, tule potato, and wapato (or wapatoo). Most are native to South, Central, and North America, but there are also some from Europe, Africa, and Asia.