Genus Marsilea refers to a group of aquatic ferns that belong to the family Marsileaceae. These plants are commonly known as water clovers due to their clover-like appearance. The genus Marsilea comprises over 60 different species, and synonyms for this term include Pilularia, Regnellidium, and Pseudocyclosorus. These synonyms are used interchangeably to describe different species of Marsilea, each characterized by their unique features, such as the number of leaflets or the shape and size of their sporocarps. Marsilea species are distributed in moist habitats, such as ponds, swamps, and rivers, and are known to play a vital role in the ecological balance of aquatic ecosystems.