"Oo-aze-suge" (Carex thunbergii var. appendiculata) belongs to Cyperaceae (the Sedge family). It is a perennial herb that is distributed from Chubu district of Honshu to Hokkaido and northern Kyushu in Japan, he Kuril Islands, northern Korea, Usuri, and Amur. This herb grows in mountainous wetlands and can reach 30-90 cm in height. The stems grow densely and form a "yachi-bozu" (tussock). The leaves are linear, 2-4 mm wide and slightly hard in quality. The 3-5 spikelets are borne on the tips of flower stalks from May to July. The 1-2 acrogyrous spikes are male and dark purple-brown to tan, and the pleurogerous spikes are female and cylindrical. The pistillate flower bract are oblong, with black-purple sides and green midribs.