Marsileaceae
Marsileaceae Mirb. is an accepted family of ferns (Polypodiopsida) in the order Salviniales, recognized by Plants of the World Online (POWO), World Flora Online (WFO), and the Pteridophyte Phylogeny Group (PPG I) classification. The family comprises three extant genera (Marsilea, Pilularia, and Regnellidium) and approximately 65–70 species, distributed worldwide in freshwater habitats. Members are unique among ferns in being heterosporous and producing characteristic hard, bean-shaped sporocarps, which are highly diagnostic.
Key characteristics
- Aquatic or amphibious perennial ferns
- Creeping rhizomes
- Leaves long-petioled with four clover-like leaflets
- Heterosporous reproduction
- Hard bean-shaped sporocarps
- Reproduction by spores rather than seeds
- Freshwater habitat
Distribution
Marsileaceae has a nearly cosmopolitan distribution, occurring throughout tropical, subtropical, and temperate regions. Members inhabit ponds, marshes, rice fields, irrigation canals, floodplains, lakeshores, wetlands, slow-moving streams, and seasonally flooded grasslands. Species are particularly diverse in tropical Asia, Africa, Australia, and the Americas. In Pakistan, Marsileaceae is found, and lower Himalayan foothills. Species occur in rice fields, ponds, irrigation channels, marshes, river margins, floodplains, wetlands, and temporary pools, particularly during the monsoon season.