Northern Prairie Wildlife Research Center
WATER-LILY FAMILY (Nymphaeaceae)
IND. STATUS: OBL
FIELD CHARACTERISTICS: An aquatic perennial herb. Leaves are elliptical with pinnate venation and a deep notch. The leaves can be floating, emerged or submerged. Floating leaves are 7-35 cm. long and 5-25 cm. wide. Flowers are yellow and (2.5)3.5-5 cm. thick. The sepals, usually 6, are petal-like and are usually red within at the base. The petals are small and scale-like. Petioles are flattened on the upper side or even winged. The rhizome is very thick (to 1 dm.) and spongy with semi-circular to triangular scars of petioles and circular scars of flower stalks. In flower during June to September.
ECOLOGICAL NOTES: Yellow water-lily is found in lakes, ponds, streams, marshes, bog ponds and Mississippi River backwaters. The flowers are a favorite food of muskrats. Other common names are cow-lily and spatter dock. A synonym is N. variegata Durand.
SOURCE: Fernald (1970); Gleason and Cronquist (1991); and Voss (1985).