It looks like a miniature pine forest

Hippuris vulgaris or Marestail is a common swamp and pond plant. This plant is counted among the oxygen plants because the underwater leaves also produce a lot of oxygen and it resembles Elodea (waterweeds) The piece that is a few decimeters above the water looks like a small pine tree. Marestail can form large masses and propagate by means of rhizomes. It prefers to grow on clay soil and in particular in brackish water. A Marestail field looks like a miniature pine forest.