Vallisneria spiralis is a submerged, dioecious perennial macrophyte belonging to the family Hydrocharitaceae. The specific epithet 'spiralis' is often a source of taxonomic confusion, as it does not refer to the morphology of its linear, tape-like leaves (which are typically straight), but rather to the tightly coiled peduncle of the female flower. This structure allows the flower to reach the water's surface for pollination and then retracts post-fertilization to allow the fruit to develop underwater. Sexual reproduction is a fascinating process of surface pollination (ephydrophily). The minute male flowers detach from a submerged spathe, float to the surface, and are drawn into the menisci formed by the larger, sessile female flowers. In aquaria, however, reproduction is almost exclusively vegetative via the production of stolons, demonstrating its high phenotypic plasticity and clonal growth strategy.
Physiologically, V. spiralis is highly efficient in nutrient sequestration, particularly of nitrogenous compounds (NH₄⁺, NO₃⁻) and phosphates, making it a valuable species for phytoremediation in eutrophic aquatic systems. Its ability to thrive without supplemental CO₂ can be attributed to its capacity to utilize bicarbonate (HCO₃⁻) as an inorganic carbon source, a common trait in hard, alkaline waters. This physiological adaptation allows it to outcompete many other plant species in CO₂-limited environments. Its broad tolerance for temperature and water chemistry is reflective of its vast cosmopolitan distribution across Europe, Africa, and Asia. This wide distribution and adaptability are factors in its IUCN Red List status of 'Least Concern' (LC). However, this same resilience contributes to its potential as an invasive species in non-native regions where it can form dense monotypic stands, altering local hydrology and displacing native flora. While a freshwater species, its tolerance for salinity up to 0.5 ppt allows it to inhabit oligohaline zones of estuaries and deltas.