Zannichellia

Zannichellia (common name horned pondweed) is a genus of submerged aquatic flowering plant, with threadlike leaves and tiny flowers. It is fully adapted to an aquatic life cycle, including underwater pollination.
There are perhaps five species, including "Zannichellia palustris".
The genus is named after Gian Girolamo Zannichelli (1662–1729), Italian botanist.