Mercurialis leiocarpa

Mercurialis leiocarpa or Yama-ai (scientific name: Mercurialis leiocarpa) is a perennial herbaceous plant of the family Euphorbiaceae, native to the Korean Peninsula, China, Indochina and Japan. It grows in clusters on the understory of mountain forests in Honshu to the Ryukyu Peninsula. It is a dye that has been used since the Man' yoshu period (710-794), and it dyes green instead of blue. The cross section of the stem is square. Dioecious.

Scientific name: Mercurialis leiocarpa, Place of origin: Korean Peninsula, China, Indochina, Japan, Distribution: Honshu to Ryukyu Peninsula, Japan, Plant height: 30-40 cm; leaf blade: opposite; leaf shape: elliptic, Leaf blade length: 10 cm, leaf margin: serrated; petiole: long, Flowering season: April-July, petals: none, uses: green dye.