The sclerotium of Inonotus obliquus appears as a tuberculous (sterile mass), black-gray in appearance, with irregular grooves, yellow in the interior, sessile, 25-40cm in diameter, dark-colored, with a deeply cracked surface, very hard, and brittle when dry. The fertile part is 5mm thick, with a thin shell, and dark brown. The tube measures 3-10mm, is brittle, and usually has a cracked front end with 6-8 holes per mm, round, light white, and then dark brown. The fungus flesh is woody, exhibiting a slight, ambiguous ring pattern, and when fresh, it appears bright yellowish-brown. The spores are broadly elliptic to ovate, smooth, measuring 9-10μm×5.5-6.5μm, and bristled. Inonotus obliquus is mainly distributed in Russia, Finland, Poland, Japan (Hokkaido), and other northern latitudes of 40~50℃, as well as in China's Heilongjiang and Jilin regions. It grows under the bark of birch, elm, alder, etc., or under the bark of living wood or on the dry wood of felled trees.