"Oze-koo-hone" (Nuphar pumilum var. ozeense) belongs to Nymphaeaceae (the Waterlily family). It is a perennial herb that is endemic to Japan, and distributed to Sorachi and Soya district of Hokkaido, Mount Gassan and Oze of Honshu. This herb grows in ponds and lakes, and can reach 20-100 cm in height. The rhizomes are creeping under grounds and bear the long petioles, and the round-cordate leaves float on the water. The yellow flowers bloom on the elongated flowering stalks from July to August. The corolla has petaloid sepals and spatulate petals. The flower is difined by the red, center stigma disk. It produces pyriform berries after flowering.