Plant of the Week
White Water Lily (Nymphaea odorata)
By Jack Greenlee
This showy member of the water lily family (Nymphaeaceae) is a beautiful plant to admire as you paddle a canoe around a lake or down a sluggish stream. The large white flowers are often fragrant, hence the specific epithet “odorata”. “Nymphaea” derives from the attractive flowers, which are suggestive of the mythological Greek nymphs, beautiful supernatural female beings thought to inhabit glades and springs.
The white water lily is recognized by its large, floating, circular leaves and large, white flowers. The waxy leaves are up to 8 inches across with a narrow v-shaped cleft where the stem attaches. The underside of the leaf is green or reddish-purple in color. The flower can be up to 5 inches wide with numerous white petals and is attached to a separate stem from the leaf. Forty or more yellow stamens surround a central ovary and disk-shaped stigma.
This plant is generally found in quiet water up to 5 or 6 feet deep and is adapted to its aquatic habitat. The stout rhizomes are spongy with hollow spaces for storing oxygen that is transported down the stems from the leaves. Occasionally a chunk of rhizome will break off and wash up on shore. Reminiscent of an octopus tentacle, these rhizomes can sprout to start new water lily colonies.
White water lily flowers are open during the daytime for three days. On the first day, the petals are not fully open and thus form a cup-like structure filled with a fluid containing sugars. The female flower structure, the stigma, is receptive to pollen only on the first day, and each flower does not produce its own pollen until the second and third days, thus preventing self-fertilization. On the first day of flowering, beetles and bees enter the flower and often fall into the fluid, which washes off pollen onto the stigma and fertilizes the flower. On the second and third days, no fluid is produced, and the flowers open wide. Insects that land on the flower on these days get covered with pollen and transport it to flowers that are just opening and hence receptive to pollination. On the fourth day, the whole structure is pulled underwater, where the seeds mature. Waterfowl and currents disperse the seeds.
This species is native to eastern North America. White water lily is cultivated as an ornamental and frequently appears in water gardens. Unfortunately, it has escaped and naturalized in some western states where it is now considered an invasive plant.