The "Miyama-irakusa" (Laportea macrostachya) belongs to Urticaceae (the Nettle family). It is a perennial herb that is native to Japan, the Korean Peninsula and China. This herb grows in montane to subalpine wettish places along streams and can reach 40-80 cm in height. The leaves are broad ovate, alternate with acute tips and toothed edges. The stinging hairs are borne on the stem and leaves. The long female clusters are borne on the upper stems and the male clusters at the middle stems from July to October. This herb is also called "Aiko" in Tohoku district of Japan and used for a wild vegetable. In Chinese, it is called "艾麻" (ai ma).