The Pacific island flatsedge (Cyperus cyperoides) belongs to Cyperaceae (the Sedge family). It is a perennial herb that is distributed from Chiba prefecture of Honshu west to Shikoku, Kyushu in Japan, and tropical and subtropical regions of Asia and Africa. This herb grows on sunny grasslands and roadsides on the beach and can reach 30 to 50 cm in height. The stem has three ridges, and broad linear leaves alternate. The columnar spikes with 6 to 7 bracts are borne on the tip of the stem from August to October. It is also called "Inu-kugu" by another name. By the way, "Kugu" is the ancient name of "Amur cyperus" (Cyperus microiria).