Marsilea L.
Mostly aquatic ferns. Rhizomes long-creeping, rooting at nodes. Lvs arising at nodes, with long stalks terminating in 4 obtriangular or flabellate segments, glabrous or hairy; veins anastomosing. Sori containing both micro-and megasporangia, protected by indusia, and contained within hard sporocarps attached near the base of the lvs. Spores trilete.
c. 50 spp., almost cosmopolitan. Naturalised sp. 1.
Marsilea spp. are easily recognised by their creeping rhizomes which often root on the bottom of ponds and produce 4-lobed lvs on long stalks that float on the water surface. The sporocarps usually develop as the pond dries out.
