1A small aquatic or semiaquatic fern which is either free-floating or anchored by the roots, found chiefly in tropical and warm countries.
Families Azollaceae, Marsileaceae and Salviniaceae: many species, in particular the minute floating Azolla filiculoides of tropical America, which has been naturalized elsewhere‘Genomic downsizing is suggested for the heterosporous water ferns and for the aquatic fern Ceratopteris.’
- ‘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.’
- ‘Avoid rampant non-natives species such as Canadian pond weed and rapidly spreading duckweeds and water ferns.’
2An Australian fern with large coarse fronds, typically growing in marshy areas and rainforests.
Genus Blechnum, family Blechnaceae: several species