Longleaf pondweed (Potamogeton nodosus)
Perennial floating leaf plant on stems up to 5 feet in length. Common to the shallow margins of ponds, lakes, and slow moving streams. Can surive in mudflats. Leaves are longer and narrower than large leaf pondweed. Spreads via rhizomes and seeds. Provides refuge for fish and amphibians. Shades water and reduces algae in ponds and slow moving rivers.