Arrowhead, Sessile-fruited - Sagittaria rigida

Sagittaria rigida is also known as Sessile-fruited Arrowhead, Grass Leaf Arrowhead, or Deep-water Duck Potato. It is a an aquatic perennial native to Michigan and the UP, especially the western UP. It grows in part shade to full sun, on the sandy or muddy edges and shallow water of rivers, ponds, lakes, swamps, and swales.
 
The long, thin leaves grow to 2' above the water line with small white flowers in mid summer. It has highly variable leaves that often do not have the characteristic arrowhead shape. They often have an oval leaf at the tip of the stem, but this can be so narrow that it is no wider than the leaf stem. A single plant can have several leaf shapes. Sessile means stalkless, and this plant can be identified by the stalkless fruit more readily than by leaf shape.
 
Sagittaria rigida is a strong spreader by rhizome. It is great for shoreline naturalization and erosion control, breaking up wakes and providing food and shelter for fish, waterfowl, and other aquatic life, including the dragonflies that eat mosquitos. Its starchy tubers are a traditional food source.
 
Plant in up to 12" of water. It may spread into water up to 24" deep.