Water Primrose

[Swede]

Water primrose is a perennial plant that stands erect along the shoreline but also forms long runners (up to 16 feet) that creep across wet soil or float out across the water surface. These runners form roots at their nodes. Leaves range from lance-shaped or willow-like (2 to inches long by 1/2 to 1 inch wide) on the erect stems to round or oval 91 to 2 inches in diameter on the floating stems. Leaves can be green to reddish depending on the species. The single flowers are yellow with 4 or 5 petals depending on the species. Flowers vary in size from 1 inch to 2 inches in diameter.

http://aquaplant.tamu.edu/database/emergent_plants/water_primrose.htm