シソ科ヤマハッカ属の多年草で、学名は Isodon umbrosus var. excisinflexus (syn. Rabdosia umbrosa var. excisinflexa)。英名はありません。
The "Tairin-yama-hakka" (Isodon umbrosus var. excisinflexus) belongs to Laminceae (the Mint family). It is a perennial herb that is distributed along the Sea of Japan coast from the southern part of the Tohoku region to the Hokuriku region on Honshu. It grows in slightly moist areas ranging from low mountains to the lower subalpine zone and reaches a height of 1 to 1.5 m. The stem is erect and square in cross-section. The leaves are ovate, 5 to 10 cm long, with a three-lobed tip; the central lobe tapers to a point like a turtle's tail, and the margins are serrated. However, many specimens do not have three-lobed leaf tips. From August to October, it produces racemes at the tips of its branches, bearing numerous pale blue to blue-purple labiate flowers. The corolla is 12-13 mm long, and the plant is characterized by its long inflorescences and large number of flowers.