The "Urashima-so" (Arisaema thunbergii ssp. urashima) belongs to Araceae (the Arum family). It is a perennial herb that is native to southward from southern Hokkaido to Honshu, Shikoku and Kyushu in Japan, as well as Taiwan. This herb grows in montane wet forests and can reach 40-50 cm in height. The leaves arepalmate compound with 11-17 leaflets. The flowering stalk is borne and a blackish purple flower covered with spathe bloom from March to June.The elongated appendix is borne from the spadix. The Japanese name "Urashima-so" (Urashima's fishing rod grass - a fisherman who rescues a turtle and is rewarded with a visit to the dragon palace in a Japanese fairy tale) is derived from the appendix shape. In Taiwanese Chinese, it is called "東台天南星".