Marsilea crenata or Four Leaf Clover Dwarf is one of the few foreground plants that doesn't demand high light and CO2. Although, supplementing CO2 ad plant nutrients could encourage faster than normal growth.
Marsilea crenata comes from the Asian and Australian tropics. Its emerged form sprouts the "four-leafed clover" leaves typical for clover ferns.
Immersed leaves are 4-lobed and the submersed leaves many have 2-4 lobes. When submerged in the aquarium it's terrestrial stem-like form transforms into a lower substrate. Shorter, more compact growth achieved in brighter light. Similar in appearance to Glossostigma, but in comparison it's leaves are leathery and thicker.
New leafes of Marsilea have brown color. Those leafes are not rotten or dead.
Planted in small bundles that spread with offshoots. Creates a 1-3cm high and close carpet, well-anchored in the bottom layer.