"Tennin-so" (Leucosceptrum japonicum) belongs to Lamiaceae (the Mint family). It is a perennial herb that is native to Japan. This herb grows in large clumps in montane tree-shaded areas and grasslands, and it can reach about 1m in height. The rhizomes are lignified and bear quadrangular stems. The leaves are oblong to broad lanceolate and arranged in opposite with acute tips. The pale yellow, labiate flowers bloom in the racemes atop of stems from August to October. The corolla is divided into five partite lobes and protrudes four stamens and a pistil. The Japanese name is derived from the flower's shape, which resembles a celestial maiden's dance.