The Water clover (Marsilea quadrifolia) elongs to Marsileaceae (the Pepperwort family). It is a perennial fern that is widely distributed from various parts of Japan to East Asia, India, and central Europe. It is a fern plant that grows in ponds, waterways, and rice fields. It grows from April to October and breeds on rhizomes and spores. The leaves have long petioles and are shaped like clovers. The Japanese name is because this leaf looks like the Chinese character "田" (rice field).