The Variable sedge (Cyperus difformis) belongs to Cyperaceae (the Sedge family). It is a perennial herb that is widely distributed from the Eurasian continent to Australia and the Pacific Islands, including various parts of Japan. It grows in damp places such as paddy fields and ridges, and can reach a height of 15-40 cm. From August to October, spherical inflorescences are attached to the tips of flower stems with three ridges, and pale green flowers come in bloom. As the seeds ripen, they become dark purple-brown. There are 3 bracts on the flower stalk.