Many Fragrant Water Lilies (Nymphaea odorata) bloom in our lake in July and August. The flowers are showy yet I had not noticed insects attracted to them, which caused me to wonder about its strategy for pollination. Investigation revealed that these plants have a very interesting reproduction process.
Each flower of the Fragrant Water Lily has a three-day life span, they close each night and open during the day.
The first day of a bloom’s life only its female portion, the stigma, is mature. The bloom does not open completely, so the flower has the form of a closed bowl. A sweet-smelling viscous fluid is secreted by the plant and fills the bottom of this bowl. Beetles, flies and other insects are attracted to this fluid. When they enter the flower, the slippery fluid causes them to fall and deposit on the stigma any pollen that they may have brought in from other flowers.
On the second and third days of a bloom’s life the pollen-producing anthers are mature and the flower opens wide to welcome pollen-spreading insects. Self-fertilization of the flower is prevented because pollen-production in each flower occurs only after the first-day fertilization of the stigma.
Once a fertilizer flower has completed its three-day cycle it closes and retracts under water to develop its seeds.
The short video below shows a Water Lily bloom bobbing with gentle waves in the lake. It seems reasonable that this bobbing action could help deposit pollen on the stigma (first day) and improve the chances that visiting insects will leave the flower carrying some of its pollen (days two and three).