Aquatic plants require special morphological, physiological and anatomical adaptations for living in aquatic environments. Aquatic vascular plants have originated on multiple occasions in different plant families: they acquired, despite evolving independently, similar growth habits (convergent evolution) because of living in a analogous environment, and so facing the same environmental factors.
In the two artificial ponds, aquatic plants are grouped according to their geographical origin:
- round pond with Europe-native plants, e.g. kingcup (Caltha palustris L.), European white waterlily (Nymphaea alba L), bog-bean (Menyanthes trifoliata L.), sweet flag (Acorus calamus L.).
- bean-shaped pond with exotic plants. This includes: the well-known papyrus sedge (Cyperus papyrus L.); the water hyacinth (Eichhornia crassipes (Mart.) Solms), with its broad, thick, glossy leaves floating above the water surface - since the roots of Eichhornia crassipes naturally absorb pollutants, the plant is cultivated for waste water treatment; Nelumbo nucifera Gaertner, commonly called sacred lotus in reference to the sacred and symbolic status the flower holds in Buddhism and Hinduism. Recent researches demonstrated that the lotus has the remarkable ability to regulate the temperature of its large, cupped, pink flowers.
At last, Azolla caroliniana Willd., a small freshwater aquatic fern, native to the Americas, naturalized and growing as wild in Italy. This plant grows very fast on backwaters pervading rapidly the environment.
