Nuphar polysepala

Nuphar polysepala (the great yellow pond-lily or wokas; syn. Nuphar polysepalum orth. err., Nuphar lutea subsp. polysepala (Engelm.) E.O.Beal) is a species of Nuphar native to western North America. The name Nuphar is Greek for "water-lily" and polysepala means many sepals. It is commonly found in shallow muddy ponds from northern Alaska and Yukon southward to central California and northern New Mexico, and can be recognized easily by its large floating leaves and bright yellow blossoms.