Inonotus obliquus, commonly called chaga (/ˈtʃɑːɡə/; a Latinisation of the Russian word чага), is a fungus in the family Hymenochaetaceae. It is parasitic on birch and other trees. The sterile conk is irregularly formed and resembles burnt charcoal. It is not the fruiting body of the fungus, but a sclerotium or mass of mycelium, mostly black because of a great amount of melanin.[2] Some people consider chaga medicinal.[3]