On the verandah we have a pot filled with water. One lonely little plant lives there. A couple of times each week we top up the water.
Occasionally, just very occasionally, there is a flower. Today there are two, well, one and a bud when I looked. The flowers are very fragile and last only a few hours. The open flower was about 4cm across. It lasted about two hours.
I think the plant is called Hydrocleys nymphoides. It looks a little like a poppy and not at all like a lotus or other water lily.