Water Lilies
Water Lilies are found in all still and slow-flowing freshwaters. One thing that I have noticed about them is that on any lake or pond, you will always find white ones, and usually also pink or yellow ones, but never both. The flowers begin in summer and last well into fall.
While the leaves and flowers are floating, the plants themselves are anchored strongly in the bottom. The stems are tough and strong, but it is possible to paddle through them with a modified stroke. Basically, pull the paddle lengthwise out of the water so that it sheds the plants.
I pulled up some plants with roots and tried to grow them in an aquarium in potting soil, but they did not do well, and eventually died. My guess is that they need full sunshine, and even very bright artificial light is just not enough. If you pick just a flower, it will last a few days in a saucer of water.