Eleocharis is a virtually cosmopolitan genus of 250 or more species of flowering plants in the sedge family, Cyperaceae.

The vast majority of Eleocharis species grow in aquatic or mesic habitats from sea level to higher than 5,000 meters in elevation (in the tropical Andes).

Many species are robust, rhizomatously-spreading plants of lowland tropical wetlands, while many others are small caespitose annual or perennial herbs growing near streams, and still others are intermediate.

Because of their difficult nature, it is suggested that many botanists avoid collecting these plants and so many species are under-represented in the botanical record.

In Australia, magpie geese rely almost exclusively on these tubers for sustenance for a significant portion of the year.