"Ooyama-hakobe" (Stellaria monosperma var. japonica) belongs to the Caryophyllaceae (the Carnation family). It is a perennial herb that is native from Iwate prefecture of Honshu south to Shikoku and Kyushu. This herb grows in wet forests, and it can reach 40-80 cm in height. The stem is branched at the upper part and hairy. The leaves are oblong-lanceolate, opposite and glabrous with entire and scalloped edges. The peduncles are born at the upper axils and bloom small white flowers in the cymose clusters from August to October. The petals are five, divided into two deeply incised lobes, and shorter than the sepals. The calyces and peduncles are covered with glandular hairs.