The water shield is a floating plant native to the United States. It is also commonly referred to as the "water target" or "dollar pad". This plant is most common in the state of Washington, but can be found almost anywhere in the world. This plant is named for the two botanists who discovered it, Brasen and Schreber, who gave it the scientific name of "Brasenia schreberi" in the late 18th century.
The plant itself grows in lakes and ponds. They are loosly rooted in the soil at the bottom of the water, and have long purple stems that reach up to the surface. These stems are each topped with a six inch leaf, that is green on top and purple underneath. The leaves are roughly shield shaped, which is how the plant got its common nickname.
The stems of the plants are very flexible, and will not break in moving water under normal circumstances. But during the summer months the stems stiffen up a bit, and produce a small flower that will rise just above the top of the water.
The purple areas of young water shields are covered in tiny hairs that secret a thick slippery gel. This makes the plant almost impossible to grab on to and maintain a grip on. This gel (and the leaves as well), have been used by the Japanese for salad ingredients. Native American tribes also used to eat these plants rather frequently, although today they are usually only eaten by fish.
The best place to find these plants are in shallow bodies of water (2-6 feet) in Washington, (although they are found all around the world, not just in Washington).