The "Kugai-so" (Veronicastrum sibiricum ssp. japonicum) belongs to Scrophulariaceae (the Figwort family). It is a perennial herb that is distributed northward from Kinki district of Honshu, Japan. This herb grows in sunny montane grasslands and can reach about 1 m in height. The> leaves are 4-8 whorled. The racemes are borne on the stem apices and bloom numerous bluish-purple flowers from July to September. The two stamens are protruded from the corolla. The Japanese name comes from the fact that the leaves are arranged in whorls of four to eight, forming multiple layers.