Nymphaea 'Helvola' is a miniature hardy waterlily with 2- to 3-inch pale yellow flowers with bright yellow stamens. The 5-inch leaves are mottled with purple. Waterlilies are rhizomatous aquatic plants with about 50 species occurring in the wild, mostly found in the tropics of the Northern Hemisphere. They are characterized by round notched leaves that lie flat on the water and flowers with numerous petals produced at the end of a long lax stem floating just above the water surface. In the center of each flower is a cluster of showy stamens. Waterlilies have been cultivated since at least 2000 B.C. and are divided into hardy hybrids, tropical day-blooming, and tropical night-blooming. Waterlilies need full sun to flower and must be anchored in mud as they are not free floating.