Potamogeton

Potamogeton is a genus of aquatic plants commonly known as pondweeds. Belonging to the family Potamogetonaceae, the genus comprises roughly 60 to 90 species distributed worldwide in freshwater habitats. They are primarily rooted perennials or annuals that inhabit ponds, lakes, slow-moving rivers, and marshes, often forming important components of aquatic ecosystems.

Morphology and reproduction: Potamogeton species are usually herbaceous and aquatic, with stems that may root at nodes. Leaves are typically simple and may be submerged, floating, or both (heterophyllous). Submerged leaves are often slender or finely dissected, while floating leaves tend to be round to oblong with longer petioles. Flowers are small and produced on slender inflorescences that emerge at or above the water surface; the flowers are generally unisexual, and pollination occurs in the water or by wind. Fruits are usually small achenes. The genus includes both creeping, rhizomatous forms and more erect, short-stemmed forms.

Habitat and significance: Potamogeton species are widespread in freshwater ecosystems and can dominate plant communities in suitable conditions. They provide habitat and food for invertebrates and fish, contribute to oxygenation, and influence sediment stability. Some species are used in aquariums and water-treatment contexts. A few, such as curly-leaf pondweed (Potamogeton crispus), are considered invasive in certain regions and can form dense stands that disrupt native communities.

Notable species: Potamogeton natans (large-leaf pondweed), Potamogeton lucens (paddle-leaved pondweed), and Potamogeton crispus. Etymology: the name derives from Greek potamos, river, and ge, earth, effectively “river plant.”