Zannichellia (common name horned pondweed)[2] is a genus of submerged aquatic flowering plant,[3] with threadlike leaves and tiny flowers.

[3] It is fully adapted to an aquatic life cycle, including underwater pollination.

[4] The genus is named after Gian Girolamo Zannichelli (1662–1729), Italian botanist.

The male flowers have a single stamen with a slender filament and anthers that are 2-4-thecous.

[5] The species of this genus are widely distributed and are found growing in temperate and tropical regions around the world.