Marsilea drummondii is a species of fern known by the common name nardoo. It is native to Australia, where it is widespread and common, particularly in inland regions. It is a rhizomatous perennial aquatic fern that roots in mud substrates and produces herbage that floats on the surface of quiet water bodies. It occurs in water up to one meter deep. It occurs in abundance after floods. It can form mats on the water's surface and cover the ground in carpets as floodwaters recede.