Nymphaea mexicana
Yellow water lilies are perennial plants that arise on flexible stalks from rhizomes and large fleshy roots that can resemble bananas. Leaves are oval heart-shape, 3 to 6 inches in diameter, shiny dark green on top and reddish-purple underneath. Leaves float on the surface and are seldom emergent. Flowers are large (2 1/2 to 4 inches) bright yellow and usually stand above the water on separate stalks.
Also known as: Mexican Water Lily