Hi
I'm not 100%sure but I know its some kind of Aponogeton. The flowers will turn into seeds if pollinated. Which is likely due to the fact that you have many runners over the water level.They do stick-up out of the water don't they? The seeds go into a mini plantlet state almost immediately. What you will see is the white flowers turn into tiny plant like green "pre-plants" then swell and fall off. You can then let them float and grow. Some will sink immediately,and will also grow. I have about 20+ 2 1/2 in. plants that grew from those exact white flowers.