Cyclosorus interruptus (Swamp shield-fern) is a fern in the Marsh Fern family, that is native to the tropics and subtropics of all the continents. In the New World, it is found from Mexico to Argentina, and in the Antilles. In the Old World, it is found in India, China, Malaysia, Sri Lanka and South Africa. It is also found in Australia, New Zealand, Hawaii and other islands in the Pacific Ocean. The various populations differ with respect to genetic cytotypes, glands, pubescence, and frond size. Its habitat is the vicinity of freshwater swamps and it may reach 1 m (3 ft 3 in) in height.