English: Four leaf clover; European waterclover.
India: Sushni.
Tamil: Aalaik keerai.
Region: central and southern Europe, Caucasia, western Siberia, Afghanistan, south-west India, China, Japan, Vietnam; introduced into the United States.
Habitat: prefers light, sandy and medium, loamy soils; grows in semi-shade, light woodland or no shade; prefers moist or wet soil and can grow in water, wet soil, semi-submerged; unfussy as to light and water conditions; doesn't need a rich substrate.
Use: food; aquarium plant.

BotanyHerb; fern; aquatic
Leaves: 4 parted leaf resembling Trifolium; floating in deep water or erect in shallow water or on land; leaflets obdeltoid, to 2 cm long, glaucous, petioles to 20 cm long; emergent from the water and floating, or fully submerged.
Sporocarp: ellipsoid, to 5 mm long, dark brown, on stalks to 20 mm long, attached to base of petioles.

Plant theoryIn the PPG1 classifcation Marsileaceae is included in the order Salviniales.
In the Plant theory Marsileaceae is sperated from Salviales and placed in its own Order Marsileales and subclass Marsileidae.