1A small aquatic or semiaquatic fern that is either free-floating or anchored by the roots, found chiefly in tropical and warm countries.
- ‘Avoid rampant non-natives species such as Canadian pond weed and rapidly spreading duckweeds and water ferns.’
- ‘However, both water ferns and Selaginella are also heterosporous, unlike any other pteridophytes except Isoetales.’
- ‘Thick mass of Trapa, an economically important free floating plant called Singhari by the local people, besides water ferns, duckweeds etc can be seen almost everywhere.’
- ‘Genomic downsizing is suggested for the heterosporous water ferns and for the aquatic fern Ceratopteris.’
2An Australian fern with large coarse fronds, typically growing in marshy areas and rainforests.